AeroSafety world PRECISION-LIKE APPROACHES USE EXISTING CAPABILITIES BETTER
insidious ice Armavia a320 at sochi Runway surface microweather Causal factors cabin air Corporate flight attendants Dry but generally harmless Getting the right training
TheFlight Journal Safety of FFoundationlight Safety Foundation OCTOBER 2007
President’sMessage Community
he air safety situation in Brazil has been an What not many people know is that, in that issue since my first day on the job at the same week, there were victories in Brazil for Foundation. Everything started unraveling the protection of safety information. The safety with the midair collision between an Em- professionals in Brazil have been fighting back. Tbraer Legacy and a Gol Boeing 737-800. Within On Aug. 7, the investigator-in-charge refused hours, the highest levels of the Brazilian govern- to provide the House of Representatives with ment engaged in outrageous finger-pointing information from the accident investigation. He and speculation. Air traffic controllers revolted cited in court a 1994 Supreme Court ruling barring against what they characterized as unsafe condi- the incarceration of people who refuse to release tions and set off national air transportation and data protected by duty or professional obligation. political crises. We will have to wait for the of- It worked. The information was protected and he ficial investigation’s conclusions, but numerous didn’t go to jail. errors and circumstances apparently combined It didn’t end there. That same morning, crimi- to cause that tragedy. That errors were made is nal prosecutors seized computers and register understandable. That many warning signs were books from some ATC facilities. The seizure was ignored is troubling. appealed to a higher court and was reversed. Since On July 17, we got another reminder of what then, there has been talk of an initiative within can happen when warning signs are ignored. A Brazil’s House of Representatives to revise their TAM A320 skidded off the runway at Congonhas laws based on best practices elsewhere for the Airport, São Paulo, killing 199 people. Again, it protection of safety data. will be a while before we know the causes, but The safety professionals in Brazil are doing this happened at a difficult airport under difficult their job. They don’t make as much noise as the conditions. Previous incidents and safety reports politicians, but they are having an effect. They had warned of problems. Unfortunately, the safety are risking their careers and their liberty to do situation wasn’t really under control of the safety the right thing. Our job in the safety community officials. Instead, judges and city politicians de- is to make sure such efforts don’t go unnoticed, bated the types of airplane that could operate on or unsupported. We must not forget that their the runway and the conditions required. fight is our fight. That is what it means to be a Another political frenzy followed the Con- community. gonhas tragedy. The most discouraging moment came on Aug. 1, when the transcript of the cockpit voice recording was made public as part of an investigation by the Brazilian House of Repre- sentatives; the international press sensationalized the last few moments of that crew’s struggle. The William R. Voss recording should have been protected as part of President and CEO the safety investigation under international law, Flight Safety Foundation but the information took pressure off politicians and officials responsible for the airport. www.flightsafety.org | AeroSafetyWorld | October 2007 | 1 AeroSafetyWorld
October2007 Vol 2 Issue 10 contents12 features
12 CoverStory | Advent of Precision-Like Approaches
22 InSight | Missing Perspectives
24 FlightOps | Insidious Ice 22 29 SafetyRegulation | Ice Protection Proposal 31 AviationMedicine | Airing It Out
38 CabinSafety | Beyond Passenger Service
44 CausalFactors | Into the Black Sea departments
1 President’sMessage | Community
5 EditorialPage | Glut
6 SafetyCalendar | Industry Events
8 InBrief | Safety News 24 36 LeadersLog | John W. Douglass
2 | flight safety foundation | AeroSafetyWorld | October 2007 44
Sochi contents 31 38 AeroSafetyWORLD telephone: +1 703.739.6700 43 FoundationFocus | Membership Update William R. Voss, publisher, FSF president and CEO [email protected], ext. 108 50 | Separation Maintained DataLink J.A. Donoghue, editor-in-chief, FSF director of publications 53 InfoScan | Handle With Care [email protected], ext. 116 Mark Lacagnina, senior editor [email protected], ext. 114 57 OnRecord | Hammered by Hail Wayne Rosenkrans, senior editor [email protected], ext. 115 Linda Werfelman, senior editor [email protected], ext. 122 Rick Darby, associate editor [email protected], ext. 113 Karen K. Ehrlich, web and print production coordinator [email protected], ext. 117 Ann L. Mullikin, production designer [email protected], ext. 120 Susan D. Reed, production specialist About the Cover [email protected], ext. 123 More-precise approaches using existing equipment. Patricia Setze, librarian © D. Satyajit [email protected], ext. 103
Editorial Advisory Board We Encourage Reprints (For permissions, go to
www.flightsafety.org | AeroSafetyWorld | October 2007 | 3 Serving Aviation Safety Interests for More Than 50 Years
Officers and Staff light Safety Foundation is an international membership organization dedicated to Chairman, Board of Governors Amb. Edward W. the continuous improvement of aviation safety. Nonprofit and independent, the Stimpson Foundation was launched officially in 1947 in response to the aviation industry’s need President and CEO William R. Voss F for a neutral clearinghouse to disseminate objective safety information, and for a credible Executive Vice President Robert H. Vandel General Counsel and knowledgeable body that would identify threats to safety, analyze the problems and and Secretary Kenneth P. Quinn, Esq. recommend practical solutions to them. Since its beginning, the Foundation has acted in the Treasurer David J. Barger public interest to produce positive influence on aviation safety. Today, the Foundation provides Administrative leadership to more than 1,140 individuals and member organizations in 142 countries. Manager, Support Services Linda Crowley Horger
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4 | SINCE 1947 flight safety foundation | AeroSafetyWorld | October 2007 Editorialpage G lut
he number of airliners being or- industry went through in the early years overcapacity and an economic downturn dered these days is nothing but of deregulation, when suddenly airlines is that airplanes and spare parts get very good news for equipment manu- could fly wherever and whenever they cheap and very available. This opens the facturers around the world. After wanted. Orders swelled then, too. It was door for people with not too much money Tsuffering through years of constrained said that each airline ordered enough and little or no aviation experience to demand after the 9/11 terror attacks exac- airplanes to single-handedly take care of acquire a few airplanes and start opera- erbated the economic decline that began all anticipated market growth. The result, tions in an area where safety regulation with the tech stock collapse at the start of of course, was too much capacity. When is lightly applied. Little attention is paid the century, manufacturers are happy to the next downturn hit, whole fleets of to maintenance and operating rules, and see buyers taking delivery positions for airliners were parked in the desert and the result is unavoidable. This has been years to come. put up for sale. the fate not only of many Soviet-era air- Steven Udvar-Hazy, chairman and I think it is safe to expect something planes flown without the necessary care CEO of International Lease Finance similar to happen in the future, but on in the developing world but also of the Corp., a company that owns more than a global scale. While the benefits of de- occasional Boeing or Airbus. No level 900 airplanes, noted in a recent interview regulation are undeniable, also undeni- of design and manufacturing magic can that for the past three years lessors and able is the fact that the industry becomes forever forestall the tragic consequences airlines have ordered airplanes at twice more volatile, more subject to economic of an unsafe hand. the rate at which they are being built, and damage as management both good and There is some breathing room be- big U.S. carriers for the most part have yet bad collides with inevitable economic fore the next glut of cheap airplanes to join the party. fluctuations. And herein lurk two safety comes around, but it would be good to While this order eruption is powered threats. be thinking about solutions now rather by the resurgence of older airlines, it is The first threat is that new airlines than later. supercharged by a large number of new going through their first bout with lean and rapidly expanding airlines that are times might, in the absence of diligent taking advantage of relaxed barriers to safety regulation, be tempted to work market entry and controls over competi- to the edges of the safety margin and tion to stimulate the air travel market to a beyond. For this problem, the answer is remarkable degree, most notably in areas simple: Regulators need to step up their J.A. Donoghue of the world where a reasonably priced vigilance when their carriers are feeling Editor-in-Chief airline ticket is an exciting novelty. the pain. AeroSafety World Some elements of this order surge The second threat is more difficult remind me of what the U.S. airline to constrain. The classic result of www.flightsafety.org | AeroSafetyWorld | October 2007 | 5 ➤ safetycalendar
FSFSeminars 2008-09 Exhibit and Sponsorship Opportunities Available
A Global Approach to European Safety March 10–12, 2008 Flight Safety Foundation and European Regions Airline Association 20th annual European Aviation Safety Seminar EASS JW Marriott Bucharest Grand Hotel, Bucharest, Romania
Corporate Aviation Safety–Innovation and Change April 29–May 1, 2008 Flight Safety Foundation and National Business Aviation Association 53rd annual Corporate Aviation Safety Seminar CASS The Innisbrook Resort and Golf Club, Palm Harbor, Florida
Corporate Aviation Safety Seminar April 21–23, 2009 Flight Safety Foundation and National Business Aviation Association 54th annual Corporate Aviation Safety Seminar CASS
Hilton Walt Disney World, Orlando, Florida Inc., iStockphoto© Dreamstime International, Getty Images Inc.
Send information: EASS CASS IASS (joint meeting: FSF, IFA and IATA) FSF membership information Fax this form to Flight Safety Foundation. For additional information, contact Ann Hill, ext.105; e-mail: [email protected].
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6 | flight safety foundation | AerosafetyWorld | October 2007 ➤ safetycalendar
OCT. 1–2 ➤ UKFSC Annual Seminar: Technical OCT. 15–19 ➤ Survival Factors in Aviation OCT. 29–NOV. 1 ➤ Fifth Triennial International Innovation and Human Error Reduction. U.K. Accidents. U.S. National Transportation Safety Aircraft Fire and Cabin Safety Research Flight Safety Committee. Heathrow.
OCT. 14–17 ➤ Wildlife Management Workshop. OCT. 24–26 ➤ Master and Commander Aviation safety event coming up? American Association of Airport Executives. Conference: Command/Leadership for Tell industry leaders about it. Minneapolis. Natalie Fleet,
www.flightsafety.org | AeroSafetyWorld | October 2007 | 7 inBrief Safety News Hot Wired
ires near the windshield heat termi- declared an emergency and returned to [service bulletin] and would resubmit it nals on two Boeing 757-200s have the airport for a safe landing. to the FAA in October 2007,” the NTSB Fprompted a recommendation by Investigations determined that both said. “The Safety Board is very concerned the U.S. National Transportation Safety fires resulted from misalignment of a that the ADs [airworthiness directives] Board (NTSB) for airworthiness direc- screw attaching the power wire to the originally scheduled to be issued as early tives requiring replacement of wind- windshield heat terminal block; the mis- as September 2004 still have not been is- shield heat terminal blocks on all 747s, alignment caused an electrical arc. sued. The Board considers any kind of fire 757s, 767s and 777s. During the investigation, Boeing told and/or smoke in the cockpit to be a seri- The NTSB also recommended that the NTSB that similar events had oc- ous issue that could affect other aircraft the U.S. Federal Aviation Administration curred in at least four other airplanes and systems, lead to a loss of visibility, provide (FAA) “complete the process begun in that the terminal block had subsequently a distraction or incapacitate the crew and 2004 to approve the service bulletin for been redesigned. The redesign was possibly lead to an accident.” the installation of the redesigned wind- included in new production airplanes be- shield heat terminal block on Boeing 767 ginning in mid-2004, about the same time airplanes.” a related service bulletin was issued for The NTSB’s recommendations were 777s. Service bulletins for 747s and 757s
prompted by a Jan. 25, 2004, fire on an were issued in 2006, but the service bulle- Williams/iStockphoto © Brett American Airlines 757 during departure tin for 767s has not been issued because from Dallas–Fort Worth International of “minor disagreements between the Airport and a Jan. 21, 2004, fire on an FAA and Boeing,” the NTSB said. Air Greenland 757 in Copenhagen, Den- “In August 2007, Boeing mark, as the airplane was being prepared informed investigators that it was for flight. The crew of the Dallas aircraft making requested changes to the 767
Runway Check
he U.S. National Transportation Safety Board (NTSB), cit- The recommendation follows the NTSB’s investigation of ing a 2006 accident in which a Comair Bombardier CRJ100 the Aug. 27, 2006, Comair accident, in which the flight crew Tcrashed during takeoff from the wrong runway in Lexing- was told by air traffic control to conduct a takeoff from Runway ton, Kentucky, U.S., has recommended action to require flight 22 but instead taxied onto Runway 26 and began the takeoff crews to confirm before takeoff that their airplane is about to roll. The airplane overran the departure end of Runway 26, enter the correct runway. which was 3,500 ft (1,068 m) long, half the length of Runway The NTSB recommendation says that the U.S. Federal Avia- 22. Forty-nine of the 50 people in the airplane were killed, and tion Administration (FAA) should require air carriers and com- one — the first officer — received serious injuries. mercial operators, commuter and on-demand operators, and The NTSB said that the probable cause of the accident was fractional ownership operators to “establish procedures requir- the flight crewmembers’ “failure to use available cues and aids ing all crewmembers on the flight deck to positively confirm to identify the airplane’s location on the airport surface during and cross-check the airplane’s location at the assigned departure taxi and their failure to cross-check and verify that the airplane runway before crossing the hold-short line for takeoff.” was on the correct runway before takeoff.” The NTSB also recommended that the FAA require opera- © Lowell Sannes/iStockphoto tors to install “on their aircraft cockpit moving map displays or an automatic system that alerts pilots when a takeoff is attempted on a taxiway or runway other than the one intended.” Other recom- mendations called on the FAA to require enhanced taxiway center- line markings and holding positions signs at runway entrances; to prohibit issuance of a takeoff clearance until after an airplane has crossed all intersecting runways; and to tell air traffic controllers to “refrain from performing administrative tasks … when moving aircraft are in the controller’s area of responsibility.”
8 | flight safety foundation | AeroSafetyWorld | October 2007 inBrief
Short-Term Safety Plan Technical Harmony
epresentatives of the U.S. Federal runway incursions and wrong-runway viation organizations in Europe Aviation Administration (FAA) departures,” the FAA said. and North America say they Rand the aviation community, The plan, adopted Aug. 15, said Awill collaborate to harmonize in response to 21 serious runway that — within 60 days — the avia- technical data standards in aerospace, incursions in the first seven months of tion community would begin safety defense and commercial aviation. 2007 and other related problems, have reviews at the U.S. airports “where In an Aug. 13 agreement, the implemented a five-point, short-term wrong-runway departures and runway AeroSpace and Defence Industries plan to improve runway safety. incursions are the greatest concern,” Association of Europe (ASD), the “Recent close calls at some of our would disseminate runway safety Aerospace Industries Association of nation’s busiest airports show that ac- information and training through- America and the Air Transport Asso- tion must be taken to reduce the risk of out the industry, would accelerate ciation of America said that they will the planned installation of improved work together to advance the develop- airport signage and markings at major ment and maintenance of the S1000D airports and would review clearance specification for the production of procedures for both pilots and air technical publications. traffic controllers. The five-point plan “This approach will harmonize also called for implementation of “a how technical data are conveyed be- voluntary self-reporting system for all tween the original equipment manufac- air traffic organization safety person- turer and user community,” the three nel, such as air traffic controllers and organizations said in a statement. technicians.” ASD Secretary General François The FAA said that in addition to Gayet said, “The cooperation on the short-term plan, “mid- and long- S1000D is further proof that our indus- term goal areas are being pursued tries can only profit from cross-Atlantic to address maximizing situational developments where both sides have awareness, minimizing pilot dis- equal value in the cooperation. From tractions and eliminating runway the manufacturers’ point of view, all incursions using procedures and solutions that simplify through stan- technology.” dardization [are] welcome.” © Baloncici/Dreamstime
Multicrew Training © Thomas Pullicino/iStockphoto ix students have demonstrated “sound two-crew proce- dures” in the first phase of training based on the Sprinciples behind a proposal for multicrew pilot licens- ing, the Civil Aviation Safety Authority of Australia (CASA) says. The students, who are from two Chinese airlines, are en- rolled in a trial course conducted by Alteon in conjunction with the Australian Airline Academy, and monitored by CASA. The training calls for extensive use of large aircraft simulators rather than general aviation training aircraft. “Through the use of high-quality visual flight simula- tors and adherence to multicrew phraseology and standard operating procedures, the ... students have demonstrated sound two-crew procedures,” a CASA report said. “This of ‘altitude’ or ‘bank angle’ to prompt the pilot flying during has started right from the ab initio stage, where the student flight maneuvers. This results in a pilot’s frame of mind that engaged in the pilot monitoring role uses the standard calls is ‘multicrew’ from day one.”
www.flightsafety.org | AeroSafetyWorld | October 2007 | 9 inBrief
Data Monitoring for Light Aircraft In Other News …
flight data monitoring and 206s and Bell 407s. The system can store ra Helicopters, with fleets in the recording system designed for more than 100 hours of high-resolution Gulf of Mexico and Alaska, has Alight aircraft has won certifica- flight data. The manufacturers said that Ebecome the first helicopter opera- tion from the U.S. Federal Aviation it also contains three-dimensional flight tor with a flight operational quality Administration (FAA). The FAA issued replay and analysis software to allow for assurance (FOQA) program approved a supplemental type certificate for the flight tracking and analysis, “including by the U.S. Federal Aviation Adminis- Aircraft Logging and Event Record- automatic analysis of flight characteris- tration. The company’s FOQA program ing for Training and Safety (ALERTS) tics to determine if the pilot adhered to also is the first approved for any U.S. system developed by Air Logistics, a standard operating procedures.” Federal Aviation Regulations Part 135 subsidiary of Bristow Group, and Ap- Flight data recording and moni- “Commuter and On-Demand” opera- pareo Systems — the first certificate for toring are among the priorities of the tor. … The International Federa- a monitoring system designed specifi- International Helicopter Safety Team, tion of Air Line Pilots’ Associations cally for small aircraft. which has called for an 80 percent (IFALPA) warns that pilots operating The FAA certification will allow the reduction in helicopter accidents around Ben Gurion Airport in Israel ALERTS system to be installed in Bell worldwide by 2016. should be prepared for interrupted
© Ivan Cholakov/iStockphoto radio transmissions because of pirate radio broadcasts, which are frequently blocking air-ground communications. IFALPA says that the Israeli Air Line Pilots Association and the Israeli Air Traffic Controllers Association have asked the government to act to end the threat to aviation safety. … Australia has authorized penalties of up to two years in prison for pointing a laser light or a similar device at an aircraft; officials say that reported cases of laser beams being aimed at aircraft have increased to about 10 a month.
Runaway Trim
he U.S. National Transportation Safety Board (NTSB), citing the ditching of a Cessna Citation 525 after a loss of elevator trim control, is recommending Tthe addition of both an aural trim-in-motion warning and contrasting-color bands on the pitch trim wheel “to provide the pilot with more timely recognition of a trim runaway condition before control forces become unmanageable.” No one was injured in the July 22, 2003, ditching in the waters of Penn Cove, Coupeville, Washington, U.S. The pilot said that, as the airplane reached 14,000 ft during a climb to Flight Level 330 (about 33,000 ft), the rate of climb decreased. He pressed the autopilot/trim disengage switch, and the airplane’s nose pitched down. He said that, as he pulled back on the control yoke, “within seconds, it was apparent that level flight was not possible.” The pilot had difficulty moving the manual trim wheel, but — with the passenger’s help, he pulled back on the control column and was able to ditch the airplane about 900 ft (274 m) from shore. The NTSB also recommended that the U.S. Federal Aviation Administra- tion require tests to ensure that the maximum control forces during a pitch trim runaway in a Citation 525 meet certification requirements and also require use of a more easily identifiable pitch trim circuit breaker. © Greg/Fotolia
Compiled and edited by Linda Werfelman.
10 | flight safety foundation | AeroSafetyWorld | October 2007
Coverstory
from Nonprecision to Precision-Like Approaches © Digital Vision /MediaBakeryVision © Digital
12 | flight safety foundation | AeroSafetyWorld | October 2007 coverStory
Second in a series focusing on the development and safety benefits of precision-like approaches, a project of the FSF International Advisory Committee.
BY ETIENNE TARNOWSKI
lying a nonprecision approach in tra- the 1980s, to the precision-like approaches of ditional nonprecision ways is less safe the 1990s and onward. than flying the same approach using the The evolution has significantly improved capabilities most transport aircraft today safety; the latest procedures, when applicable, Fpossess to fly a nonprecision approach in a have suppressed the main causes of unstabi- precision-like manner. The FSF Approach and lized approaches and, thus, have minimized Landing Accident Reduction (ALAR) Task the risks of CFIT during final approach and Force found that more than half of the accidents runway excursions and tail strikes during and serious incidents involving controlled flight landing. into terrain (CFIT) occur during step-down Any type of instrument approach procedure nonprecision approaches. Other data showed to a runway is a defined lateral and vertical tra- that nonprecision approaches are five times jectory to be flown in instrument meteorological more hazardous than precision approaches. conditions down to the published minimum al- The FSF International Advisory Committee titude, where the required visual references must believes there is insufficient attention being paid be acquired to safely continue the approach and to the potential of using procedures that create landing. precision-like approaches — how to fly them A non-ILS approach has a lateral path sup- and how to design and approve them — despite ported by a radio navigation aid (navaid) and a the fact that most aircraft and flight crews are vertical path defined in a more-or-less discon- capable of using them. tinuous way. With the advent of navigation The methods and operational procedures sensors and airborne navigation equipment that have been recommended by aircraft manu- such as the global positioning system (GPS) facturers, airlines and operators for flight crews receiver, inertial navigation system (INS) and to fly non-ILS (instrument landing system) flight management system (FMS), the area approaches have evolved over the past 35 years. navigation (RNAV) point-to-point method of They range from the traditional step-down navigation, which is not dependent on ground- approaches — also known as “dive-and-drive” based navaids, has allowed more flexibility or “stairway” approaches — of the 1970s, to the in the definition of final approach lateral and constant descent angle/stabilized approaches of vertical paths. www.flightsafety.org | AeroSafetyWorld | October 2007 | 13 Coverstory
Traditionally, most instrument final ap- form the final approach trajectory. The navaids proaches have been flown “straight in” or, when include nondirectional beacons (NDBs), VHF clear of clouds, continued with a circle-to-land omnidirectional radios (VORs) and localizers procedure. With the modern flexibility, seg- (LOCs) often paired with distance measuring mented or curved final approaches have been equipment (DME). defined. They are called nonprecision approaches because their overall performance is dictated Non-ILS Approaches by the performance of the navaid — for ex- The non-ILS approaches typical of the 1970s ample, plus/minus 5 degrees for an NDB, plus/ are referenced to ground-based navaids used to minus 3 degrees for a VOR — and the location of the navaid — on the airport, close to the airport, on or off the extended center- line of the runway, and because there is no vertical path guidance. While the avail- ability of DME helps the flight crew maintain aware- ness of the airplane’s position along the lateral path, nonpre- cision approaches are characterized by poor definition of the vertical path of the final approach. Vertical path defini- tion is partial and discontinuous, and often is provided only by an assigned altitude at the final approach fix (FAF) and by the distance from the FAF to the missed approach point (MAP). Thus, the crew’s awareness of the airplane’s verti- cal position versus the intended vertical path of the final ap- © Chris Sorensen Photography proach is quite low.
14 | flight safety foundation | AeroSafetyWorld | October 2007 coverStory
The advent of RNAV approaches in the Required Navigation Performance Approach 1980s allowed adequately equipped airplanes to be flown point-to-point based on latitude and longitude coordinates that were assigned cross- ing altitudes. Consequently, RNAV approaches clearly define both a lateral and a vertical trajectory. From the 1990s onward, required navigation performance (RNP) RNAV approaches have been defined basically as RNAV approaches with a performance-based concept, meaning that the airplane is capable of flying the RNAV approach trajectory meeting specific RNP ac- curacy levels — 0.15 nm, for example. Thus, the N E - 3 7 ,
airplane’s navigation system must monitor its 0 3 0 0 2 A P actual navigation performance (ANP) — typi- U E G S 2 7 0 2
cally, total navigation error, including system 0 o 7 G N U E E P A S 2 0 3 0 7 0 o 7 0 3 2 - t t , , t t - 3 0 0 7 o 3 2 2 A S E E P N U G 7 o
NOT FOR NAVIGATION 0 2 error and flight technical error — and has to 0 7 2 S G E U
identify whether the RNP is actually being met P A 2 0 0 3 0 , 7
during the approach. 3 - E The performance-based concept ensures N that the airplane remains contained within the specified volume of airspace, without requir- ing an outside agent to monitor its navigation accuracy and integrity. This concept gives great flexibility to approach designers; indeed, the notion of containment allows designers to consider approach trajectories that can satisfy various complicating and potentially conflicting constraints such as terrain, noise, environment and prohibited areas. The concept ensures a comfortable, flyable, constant descent angle ver- tical path, with approach minimums dictated by RNP. Figure 1 is an example of an RNP RNAV Source: U.S. Federal Aviation Administration approach procedure. Figure 1 Position-Fixing The methods and procedures recommended to Other systems, such as long-range navigation fly non-ILS approaches obviously depend upon (LORAN) and Omega, were used for long-range the ability of the on-board equipment to ensure navigation where accuracy requirements were the functionalities of navigation, guidance and relatively low. display. Two major steps forward in the 1980s were In the 1970s, the navigation functional- the widespread use of INS and the adoption ities essentially were based on equipment that of the FMS. Many transport airplanes were received radio navigation signals from ground- equipped with a least one INS, which com- based stations. Some airplanes had an INS that putes the airplane’s position autonomously, could be updated by ground-based signals. and at least one FMS, which also computes the www.flightsafety.org | AeroSafetyWorld | October 2007 | 15 Coverstory
airplane’s position. The FMS provides lateral The enhancements to FMS performance allow and vertical flight planning functions by string- the ability to fly any type of non-ILS approach ing together all the legs of a flight, including the with great precision and, thus, to meet RNP approach. The FMS can assign crossing altitudes criteria. at various waypoints of the approach, as well as Additionally, specific FMS “approach” a descent angle for specific legs, such as the final modes have been developed to provide flight approach. crews with common methods and procedures From the 1990s onward, the major advance when flying any straight-in approach, ILS or in navigation technology has been achieved non-ILS. These modes are part of the integrated through the use of GPS, which is accurate, approach navigation (IAN) system in Boeing available worldwide, able to reliably specify airplanes and the FMS landing system (FLS) in its performance and capable of monitoring Airbus airplanes, in which the FMS computes a its integrity. GPS is used as a primary naviga- virtual “beam” to the runway, based on the FMS tion source by the FMS. The resulting FMS- flight plan, as illustrated by Figure 2. These new computed position is extremely accurate. The modes allow the crew to monitor deviations navigation databases used by the FMS have been from the beam and make corrections similar to upgraded, and, whenever required, the descent an ILS approach. Figure 3 is an example of an angles assigned to specific legs also are included IAN-adapted display. in the database for a better determination of ap- proach profiles. Increased Awareness Displays present the crew with the informa- Tracking a Trajectory tion required to adequately monitor a non-ILS Guidance functionalities used by crews to fly ap- approach. proaches in the 1970s included the conventional The essential information provided in the attitude director indicator (ADI), vertical speed 1970s was the position of the airplane rela- indicator (VSI) and altimeter. Early autopilots tive to the intended lateral trajectory of the and flight directors with basic modes aided in approach — that is, the current radial to the Enhancements to the crew’s ability to fly instrument approaches. reference navaid versus the intended approach In the 1980s, guidance functionalities were radial. FMS performance greatly improved by the “glass cockpit,” in which This information was displayed by the the electronic flight instrument system (EFIS) radio magnetic indicator (RMI) during NDB allow the ability to fly featured new guidance cues such as the flight and VOR approaches, and by the electronic any type of non-ILS path vector (FPV). The FPV assists the crew in horizontal situation indicator (EHSI) for VOR stabilizing segments of trajectory, particularly and LOC approaches. The addition of DME approach with great during final approach. improved the crew’s awareness of the airplane’s The FMS developed further and allowed position along the bearing indicated by the precision. additional autopilot and flight director modes EHSI or RMI. better suited for tracking a trajectory. These In this period, the crew’s awareness of the guidance enhancements included lateral naviga- airplane’s vertical position versus the intended tion (LNAV) and vertical navigation (VNAV). vertical path generally was very poor. The VSI, From the 1990s onward, guidance function- altimeter, clock and DME were used to esti- alities have been improved by increased use of mate the airplane’s position. The advent of EFIS the head-up display (HUD) and by continued displays in the 1980s brought the primary flight enhancements of the FMS. The basic flying display (PFD) and the navigation display (ND), reference in a HUD is the FPV, which allows the which is directly linked to the FMS. crew to control the airplane’s trajectory in rela- Linking the FMS to the ND greatly im- tion to external references, such as the runway. proved the crew’s lateral orientation by showing
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the direct relationship of the current path to the FMS Landing System Beam intended path. The PFD displays the vertical de- viation from the intended final approach path, as selected in the FMS. Since the 1990s, display functionalities FLS beam have been further enhanced to the point that most non-ILS approaches can now be flown as Anchor point runway precision-like approaches, provided that the threshold/TCH adapted pieces of information are displayed for crew situational awareness. Furthermore, the development of the RNP performance- Slope based concept has led to specific monitoring FAF requirements. The evolution of display functionalities Source: Etienne Tarnowski may be summarized as follows: profile views of the approach displayed at the bottom of Figure 2 the ND for enhanced vertical situational awareness; and, on the PFD and ND, displays Profile View on Display adapted to RNP, which has lateral and vertical deviation scales and annunciations tailored to IAN or FLS.
Factors Affecting Procedures As noted earlier, the methods and procedures recommended to fly non-ILS approaches de- pend on the nature of the non-ILS approach and the on-board equipment. The procedures are affected by additional factors associated with the approach. One factor is the position of the FAF, which is either defined as a geographical point on a straight-in approach or estimated by the crew — for example, at the end of the procedure turn of a teardrop approach. Another factor is the position of the MAP, which may be located at the runway threshold or before or beyond the runway threshold. The nature of the minimum altitude also affects the procedure. No altitude loss below the minimum descent altitude (MDA) is allowed during the approach and go-around. This ap- plies to either the level-off at the MDA or, in the case of a constant descent angle, a go-around initiated before reaching the MDA, to keep from going below that altitude. This is not required Source: Etienne Tarnowski when the minimum is a decision altitude (DA). If the required visual runway environment Figure 3 www.flightsafety.org | AeroSafetyWorld | October 2007 | 17 Coverstory
references are not acquired when reaching the procedures. Both methods assumed that the DA, a go-around must be initiated. airplane was being flown in the landing con- Considering all these factors, let us review figuration and at the final approach speed from the evolution of non-ILS approach procedures the FAF down to the landing or initiation of in the three periods discussed. a go-around. One method was the traditional The non-ILS approach procedures in step-down/dive-and-drive/stairway method, as the 1970s were the traditional nonprecision illustrated by Figure 4. This involved using the approaches using NDBs, VORs, LOCs and, autopilot pitch or vertical speed mode, leveling possibly, DME as reference navaids. On-board off at the step-down altitudes and at the MDA, equipment was conventional in terms of naviga- and transitioning to a visual final approach tion, guidance and display functionalities. Two and landing. This method involved flight path types of methods and procedures were recom- changes at low altitudes. mended; they differed only in the control of the For non-FMS/non-glass-cockpit airplanes, vertical flight path, whereas the control of the the traditional dive-and-drive method was rec- lateral flight path was similar. Also common ommended down to MDA. The recommended then, as today, was the recommended use of the procedure was to select a vertical speed of 1,000 autopilot to reduce workload and provide more fpm at the FAF, level off at the next step-down precise tracking. altitude and monitor DME or make altitude Lateral flight path control was accom- checks as available — and to repeat these steps plished by tuning the reference navaid, setting to MDA. If the required visual references were the RMI and EHSI for the approach to be not in sight at an altitude equal to MDA plus 10 flown, and setting the final approach course as percent of the descent rate — for example, MDA a target trajectory. Most crews used the head- plus 100 ft for a typical 1,000 fpm descent rate ing mode to track NDB approaches and the — the vertical speed was reduced to level off at LOC or VOR mode for those approaches. Once the MDA. visual references were acquired, at MDA at the This method could result in reaching mini- latest, the approach was completed visually and mums past the published or calculated visual manually. descent point (VDP). The VDP is the last point Control of the vertical path was ac- from which a stabilized visual descent to the complished by two different methods and runway can be conducted. When not provided on the chart, the position of the VDP can be Dive and Drive estimated by the crew either as a distance to the runway threshold or as a period of time to fly from the FAF. 2500' Decision at VDP: This method was recommended for all V/S r Descent from VDP or nonprecision approaches by some operators r Go-around 1670' that often flew NDB approaches without DME V/S and without a published vertical descent angle or rate of descent, so as to have a common pro- V M MDA(H) cedure for all non-ILS approaches they flew. However, this traditional step-down ap- proach method has drawbacks. The airplane FAF D5.0 VDP MAP is never stabilized during the final approach. The pitch attitude needs to be changed even at low altitudes; thus, thrust and pitch have to be Source: Etienne Tarnowski continually adjusted. Additionally, the airplane Figure 4 reaches the MDA in level flight either before
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or after the VDP. Consequently, pitch attitude Constant Descent Angle affects the acquisition of visual references and visual perspective of the runway. Furthermore, Decision before MDA(H)/VDP or at DA(H)/VDP: if past the VDP, the crew is tempted to continue rDescent from VDP 2500' visually at a high descent rate. This technique or rGo-around leads to unstabilized approaches, which have been shown to result in off-runway touchdowns, 1670' runway excursions/overruns and tail strikes. V M Constant Descent Angle MDA(H) or DA(H) The second method that evolved during the
1970s was the constant descent angle approach, FAF D5.0 VDP MAP which enables the crew to continue a stabilized approach to a landing once visual references have been acquired (Figure 5). Source: Etienne Tarnowski The principle of this method is for the crew Figure 5 to compute a vertical speed adequate to fly from the FAF to the VDP on a constant descent angle. This is a function of average groundspeed dur- of the runway is familiar, which allows a proper ing approach. Some approach charts provide a assessment of whether the approach can be table of altitude versus groundspeed to enable continued visually and safely. The transition to the crew to fly a constant descent angle. If such a visual flight is continuous, and monitoring of table is not provided, the crew must estimate the the vertical path is simple. time between the FAF and the VDP to establish the required vertical speed. The Concept of Trajectory Consequently, during the intermediate ap- In the 1980s, RNAV approaches were added to proach segment, the crew estimates the average the mix of non-ILS approaches. EFIS and glass groundspeed, determines the constant vertical cockpits, FMS and improved flight director speed to be flown and estimates the VDP if one is modes favored the concept of trajectory with not published. Upon reaching the FAF, the vertical improved flight planning. Consequently, lateral speed mode is selected and the appropriate descent and vertical guidance, referenced from the FMS rate is established. The descent must be monitored position, could be provided along a trajectory by distance/altitude checks or the elapsed time if retrieved from the FMS navigation database. DME is not available. The monitoring must be The improved guidance capability allowed increased as the airplane nears the VDP. the tracking of this approach trajectory with No descent below MDA is allowed if the little vertical deviation. While some operators required visual references are not acquired; a go- still recommended the traditional step-down around must be initiated immediately. No level- method, they also took advantage of the map off at the MDA should be considered, because display for improved lateral situational aware- with most published MAP positions, delaying ness. Many operators adopted the procedures the go-around decision would not allow the recommended by the manufacturers, which crew to complete a stabilized visual segment. took advantage of FMS features to support con- The advantage of the constant descent angle stant descent angle approaches. approach method is that the airplane is stable Two precautions applied to full use of the during the final approach, with pitch attitude, FMS. The first was that the crew had to ensure speed, thrust and pitch trim remaining constant. that the FMS position was accurate and that When reaching the VDP, the visual perspective its accuracy was within the tolerances of the www.flightsafety.org | AeroSafetyWorld | October 2007 | 19 Coverstory
approach — typically, within 0.3 nm. If the ac- required visual references are acquired before curacy was within tolerances, the LNAV/VNAV or upon reaching the DA, the crew disen- modes and displays could be used. If not, other gages the autopilot and hand-flies the rest of lateral and vertical modes had to be used, and the approach visually, maintaining the same The coming of GPS a display of raw data had to be monitored for descent path to land. If the required visual situational awareness. An inaccurately com- references are not acquired, a go-around must in the 1990s … has puted position directly affects the performance be conducted. of FMS guidance and renders the map display The methods and procedures recom- greatly affected misleading. mended during the 1980s emphasized stabi- the way non-ILS The second precaution was that the crew lized approaches and constant descent angle had to check the quality of the FMS naviga- approaches. The advantages of a stabilized approaches are tion database. The final approach could not approach are better horizontal and vertical be modified by the crew. Therefore, the crew situational awareness, speed awareness and flown. was required to check the FMS waypoints for energy awareness, with thrust being main- final approach against those published on the tained close to the level required to fly the approach chart. If these two precautions were final approach descent angle at the final ap- satisfied, the FMS and its associated guidance proach airspeed. modes and display functionalities could be The constant descent angle approach ensures used. a profile that offers greater obstacle clearance along the final approach course, a technique and Segment by Segment procedure similar to those for an ILS approach, The constant descent angle approach method significantly reduced crew workload, a pitch at- can be summarized by looking at the initial, titude that facilitates acquisition of visual refer- intermediate and final approach segments. ences to land, and greater fuel efficiency and less During initial approach, the crew checks FMS noise impact on nearby communities. navigation accuracy and selects the reference navaid raw data. Then, the crew checks the final GPS Precision approach as inserted in the FMS against the The coming of GPS in the 1990s, with its published procedure, paying particular attention extremely high navigation performance and to the DA. integrity-monitoring capability, has greatly During the intermediate approach, the crew affected the way non-ILS approaches are flown reduces airspeed and configures the airplane in and has allowed full implementation of the RNP the landing configuration. The final approach performance-based concept. radial is intercepted via the FMS navigation In addition, the enhancement of display and mode or an intercept to the FMS final course. guidance functionalities has further reinforced The crew must monitor the interception with the stabilized/constant descent angle final ap- raw data and ensure that the correct mode is proach method. Thus, all non-ILS approaches selected to track the radial on final approach. now can be flown like ILS approaches and, due Prior to reaching the FAF on final ap- to GPS, may be considered as precision-like proach, the crew must ensure that the airplane approaches. is established in landing configuration and at Two methods are recommended today to the final approach airspeed. At the FAF, the fly precision-like approaches. Which method crew must ensure that the airplane descends is appropriate depends on the geometry of the on the proper path using the appropriate FMS approach and the aircraft equipment. mode, then monitor the descent both vertically The first method involves the use of final and horizontally, and set the missed approach approach — LNAV/VNAV — autopilot guid- altitude in case a go-around is required. If the ance modes and is applicable to all approaches
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coded in the FMS navigation database. The Further enhancements of navigation ac- procedure is similar to the previously discussed curacy eventually will allow autopilot-coupled constant descent angle/stabilized approach nonprecision approaches to very low visibility procedure. The same precautions must be limits and autolands. Such approaches already taken regarding checking FMS navigation have been demonstrated. accuracy; however, because GPS monitors its performance and integrity, the crew receives Conclusion alerts when the navigation performance is not The completion of a non-ILS approach is one of satisfactory, GPS capability is lost or the RNP the most challenging and demanding phases of level is not satisfied. The same precautions also flight. Proper planning and significant strictness by must be taken regarding checking for correct the flight crew are required in the conduct of the coding of the final approach waypoints in the approach, including task sharing, crew coordina- FMS database. tion, risk awareness and proper decision making. The same flying technique applies, but with The methods and procedures recommend- these considerations. If an RNP RNAV ap- ed to fly such approaches have significantly proach is being flown, the deviations provided changed over the past decades. Unfortunately, on the PFD are scaled to RNP. Because VNAV the initial step-down/dive-and-drive meth- is guiding the airplane on the flight path angle ods are still widely used, even by crews of the Stabilized, constant provided by the FMS, if the outside air tem- latest-technology airplanes, despite the flaws, perature (OAT) is significantly lower or higher weaknesses and drawbacks that these outdated descent angle than standard, the barometric VNAV guidance methods have exhibited in line operations. final approaches will guide the airplane on a shallower or steeper Today, stabilized, constant descent angle final flight path than expected. This explains why ap- approaches significantly raise the safety level of this significantly raise proach charts specify minimum and maximum flight phase. With the spread of GPS and the latest OATs to operate with VNAV. These approaches technology glass-cockpits, all non-ILS approaches the safety level of are flown down to the DA or MDA, depending can be flown using the latest methods. The result- this flight phase. on local regulations. ing procedures are very similar to the procedures The second method involves the use of recommended to conduct ILS approaches. the Airbus FLS or Boeing IAN mode. These Furthermore, the extremely high accuracy guidance modes apply to all straight-in non- of GPS, associated with the high performance ILS approaches coded in the FMS navigation of the lateral and vertical modes of the autopilot database. The main goal of the modes is to fly and flight director systems, makes the conduct such approaches as “ILS alike,” which means of non-ILS approaches very precise. that the procedures recommended to flight This explains the change in the operational crews for both ILS and non-ILS approaches are vocabulary from nonprecision approaches nearly identical: same sequence of actions, same to ILS-like approaches to precision-like controls and same displays. approaches. ● Because these approaches are flown using Airbus, Boeing Commercial Airplanes, Bombardier the FMS navigation database, the same two Aerospace, Jeppesen, Naverus, Northwest Airlines and precautions apply as in full use of the FMS de- Qatar Airways contributed to the research and prepara- scribed earlier: check the coding of the approach tion of this report. waypoints and check FMS position accuracy. Capt. Etienne Tarnowski is an experimental test pilot at The approach is then flown using procedures Airbus. He supervised the definition, design and develop- ment of the A310/A300-600 FMS and A320 avionics, and identical to flying an ILS approach. However, coordinated the overall operational definition of the A330 when reaching DA (or MDA), the crew has to and A340. Tarnowski is a 1967 graduate of the French disengage the autopilot and hand-fly the final Air Force Academy and a 1975 graduate of the Ecole segment down to landing. Supérieure d’ Electricité. www.flightsafety.org | AeroSafetyWorld | October 2007 | 21 insight
Missing Perspectives The most frequently reported in-flight medical events typically are not those that present the greatest threat to safety or to piloting careers.
BY QUAY SNYDER, M.D.
he recent AeroSafety World article on Loss of consciousness, which accounted for flight crew illnesses (ASW, 8/07, p. 22) nine of the 39 impairment reports, was the most provides valuable insight into illnesses frequently cited cause, followed by gastrointes- and injuries affecting flight crews dur- tinal and neurological (six cases each), cardiac Ting flight. The relative frequency of diseases (five cases) and urological (three cases). Four of categorized according to organ system — as the cardiac events resulted in pilot deaths but no reported by flight crews to MedAire’s MedLink passenger fatalities. Of the 11 cases of incapaci- in-flight medical advice program — is impor- tation, four involved respiratory causes; there tant in determining fitness for any single flight. were two reports each for problems associated The five largest categories — ear/nose/throat, with fatigue and vision, and one report each for gastrointestinal, orthopedic, infectious disease problems involving cardiac and gastrointestinal and respiratory — make up nearly two-thirds of causes and infectious disease. There were no pi- all reported in-flight medical events. lot deaths due to impairment, but three serious However, two other perspectives on illness injuries occurred as a result of crew fatigue. are important to consider when assessing safety These FAA figures reflect a substantially and career impact on pilots: the risk of in-flight different distribution of diseases than those incapacitation or impairment and the impact reported to MedLink crew support services by on medical certification. Interestingly, medical pilots and flight attendants. categories making up the majority of both the safety-compromising and career-threatening Pilot Medical Certification InSight is a forum for medical conditions affecting flight crewmem- Medical conditions adversely affecting medical expressing personal bers do not overlap with the most frequently certification are routinely reported to the joint opinions about issues of reported categories of in-flight illnesses. Virtual Flight Surgeons (VFS)/Air Line Pilots importance to aviation safety and for stimulating Association, International (ALPA) Aeromedical constructive discussion, Incapacitation and Impairment Office, which provides aeromedical certification pro and con, about the A 2004 U.S. Federal Aviation Administration assistance to about 9,000 pilots a year. expressed opinions. Send (FAA) report said that 39 cases of pilot incapaci- Medical conditions potentially affecting pilot your comments to J.A. Donoghue, director of tation (inability to perform any in-flight duties) medical certification demonstrate a different publications, Flight Safety and 11 cases of pilot impairment (some ability distribution than in-flight illness and the in- Foundation, 601 Madison to perform limited in-flight duties, although flight incapacitation experience. This difference St., Suite 300, Alexandria performance may be degraded) were reported may reflect pilot concerns regarding medical VA 22314-1756 USA or [email protected]. among U.S. airline pilots from 1993–1998 (Flight certification issues that do not directly affect Safety Digest, 1/05, p. 1).1 their personal decisions to fly on a particular
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day. The difference may also indicate non‑prescription medications,” the FAA should consult a trained aerospace that medical conditions that affect cer- does not publish a list of authorized medicine professional for both personal tification by the FAA are not propor- medications for use by flight crewmem- health and aviation safety reasons. ● tional to the conditions that historically bers or air traffic controllers. Flight Quay Snyder, M.D., is president and CEO affect in-flight impairment, incapacita- attendants are not required to hold FAA of Virtual Flight Surgeons, an aeromedical tion or inquiries regarding illnesses. medical certification/qualification. consulting firm, and an associate aeromed- Approximately 25 percent of The U.S. National Transportation ical adviser for the Air Line Pilots Association, inquiries to the VFS/ALPA Aeromed- Safety Board (NTSB) has recom- International. He also is a commercial pilot with 2,400 flight hours, a flight instructor and a ical Office involve cardiac conditions. mended that the FAA publish such a U.S. Federal Aviation Administration desig- This percentage has decreased over list, but there are drawbacks to doing nated pilot examiner. He is a member of the the previous 25 years from a high of so, including: Flight Safety Foundation Corporate Advisory approximately 35 percent, presumably • The primary safety concern re- Committee and the National Business Aviation because of the overall improvement in lated to use of a medication is the Association Safety Committee. cardiovascular health of Americans. underlying condition for which Note Inquiries about psychiatric and the medication is used. Frequent- psychological conditions are rising 1. DeJohn, C.A.; Wolbrink, A.M.; Archer, ly, relatively safe medications are J.G. In-Flight Medical Incapacitation and steadily in percentage; the current level used for medical conditions that Impairment of U.S. Airline Pilots: 1993 to is about 25 percent. This upward trend are not compatible with flight 1998, DOT/FAA/AM-04-16. U.S. Federal may reflect the general population’s safety. Publishing a list might im- Aviation Administration Civil Aerospace increasing recognition of mental health ply that use of the medication is Medical Institute. October 2004. conditions and health professionals’ authorized for any purpose. This increasing willingness to diagnose and is not the case; and, Typical Mix of Inquiries About treat them. • Maintaining an accurate, up- Medical Certification Issues* Psychiatric conditions did not result to-date list would be difficult. in in-flight incapacitation or impair- Approximate Hundreds of new medications Category of Disease Percentage ment in the FAA study. The AeroSafety by Organ System of Case Mix and formulations are approved World article about in-flight medical Cardiac 25 annually by the U.S. Food and advice did not individually identify Drug Administration (FDA). Psychiatric 25 mental health issues as a source of Many over-the-counter prepara- Neurological 8 inquiries. tions and nutritional supplements Urological 8 Other major categories of medi- are not regulated by the FDA. Vision 8 cal conditions resulting in requests to Gastrointestinal 5 the VFS/ALPA Aeromedical Office for As the article mentioned, flight and Ear/nose/throat 5 information and assistance with medi- cabin crewmembers may face supervi- Endocrine 4 cal certification include neurological, sory pressures to perform flight duties Musculoskeletal 4 urological, vision, gastrointestinal, ear/ when they are ill or taking medications. Hematological 3 nose/throat, endocrine, respiratory, Unfortunately, supervisory personnel Dermatological 1 dermatological, reproductive, hemato- rarely have aeromedical expertise or Reproductive 1 logical and other conditions (Table 1). knowledge of current FAA medication Respiratory 1
Many inquiries are related to the legal- policies. Crewmembers who acquiesce © Max Delson/iStockphoto Miscellaneous (sleep apnea, 3 ity and prudence of using medications to these pressures may be jeopardizing AIDS virus, dental, etc.) for these conditions. their health, risking their careers or *Based on calls received by the joint Virtual compromising aviation safety. Flight Surgeons/Air Line Pilots Association, Medication List Individuals seeking information International Aeromedical Office. Percentages vary by year. Although the AeroSafety World article about the safety of flying with a medi- Source: Quay Snyder, M.D. says that “pilots readily can receive cal condition and the legality of the FAA advice on prescription and treatment prescribed for that condition Table 1 www.flightsafety.org | AeroSafetyWorld | October 2007 | 23 FlightOPS
he wide range of slippery conditions on ideally were able to consider the correlation runways contaminated by frozen water still of aircraft braking friction coefficient with challenge even flight crews highly experi- runway-surface temperature, the amount of wa- enced in winter operations. But accident ter vapor close to the surface and the exact type investigatorsT in recent years have been pressing of frozen contamination. Significant changes in for a wider understanding of the basic ice physics the type of frozen contamination, such as rapid responsible for catching pilots off guard (ASW, freezing of water, may happen in the course of 2/07, p. 22). Runway-surface temperature — and minutes. Real-time broadcast of surface tem- its relationship with the dew-point or frost-point perature for a dry or wet runway could be used temperatures of the adjacent air — may indicate to predict the likely freezing of liquid water or either the possibility of water freezing or the cur- formation of frost from water vapor, as well as rent state of the frozen water, and may improve the microtexture of frozen contaminants. flight crews’ assessment of runway-friction prop- Findings from recent accident investiga- erties, including times when the surface seems tions have urgent practical implications. One is free of frozen contamination. Because freezing that airport surface air temperatures reported occurs on at least 30 percent of the Earth’s non- to pilots via routine aviation weather reports glaciated land, such knowledge can reduce risk in (METARs) may be misleading with respect to takeoff and landing. actual runway-surface conditions. Another is More realistic estimates of aircraft decelera- that flight crews should interpret conserva- tion performance could be made if flight crews tively all reports of friction coefficients based Insidious ICE
Basic physics makes slippery-runway issues crystal clear.
By Reinhard Mook
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on data collected by the friction-measurement Phenomenal Friction devices carried or pulled by airport vehicles Friction, though not yet understood completely, — and consider these reports as qualitative is believed to be caused by electric force acting information, not as quantitatively precise between molecules of two surfaces, and affects measurements. the interaction of materials on a molecular These cautions are supported by my recent scale. “Kinetic friction” means the total fric- micrometeorological field work as an indepen- tion of a “slider,” essentially an object moving dent researcher at Norway’s Svalbard Airport while in contact with another. For example, Longyear and analyses of slippery runway friction between an aircraft tire as the slider and incidents for the Accident Investigation Board a frozen contaminant depends on shear forces Norway (AIBN), SAS Scandinavian Airlines and transferred by the actual contact area of their the former Norwegian airline Braathens SAFE. In microscopic surface elevations, or high spots — my research, the label “frozen contamination” on which scientists call asperities — so deceleration Current and runways may mean compacted snow, “black ice” depends on the microtexture of the frozen con- accurate runway- — transparent/invisible ice — or ice generated tamination. The slipperiness of frozen contami- surface temperature from sintered1 snow, frozen slush, hoar frost and/ nation on the runway also can be differentiated measurements are or glaze from freezing rain, and may appear in by how ice asperities’ microscopic “peaks” and proving to be crucial various changing stages or as consecutive layers. “valleys” vary within the microclimates of frozen to assessing frozen Water freezing at 0 degrees C (32 degrees F) is contaminants because of adhesion and Kelvin contamination. assumed in this article.2 effect, in which maximum evaporation occurs At the International Society of Air Safety In- from these peaks, also called tips. vestigators seminar in August 2007, Knut Lande The special case of friction involving frozen of the AIBN reviewed unresolved issues concern- contamination seems to deviate from classical ing winter operations and friction measurements. laws of physics because it also depends on load The AIBN says that aircraft operators should not and sliding velocity. Because the heat conduction rely solely on runway friction coefficient reports within rubber is poor, most of the heat generated
© Dany Farina/iStockphoto © Dany generated by airports if frozen contamination by friction — for example, while the aircraft tire ICE is present or wet/damp conditions exist and the contacts the runway surface — is conducted into “spread” between dew point and METAR air the asperities of the frozen contaminant, such as temperature is 3 kelvins (K; 3 degrees C, 5.4 de- ice. Rather high flash temperatures — maximum grees F) or less. Scientists use the kelvin, formerly temperatures attributable to friction — occur called degree Kelvin, as the unit of thermody- in the contact area, which changes during the namic temperature. Based on an international landing roll because the asperities of the ice are agreement in 1873 about synoptic observations subject to mechanical deformation and melting by weather stations — later including METARs as a result of the tire sliding.5 This friction also is — air temperatures are measured at 2.0 m (6.6 controlled by the volume of liquid water present ft) above ground level to represent the general due to processes such as precipitation and melt- climate and to reduce the influence of the local ing, and frictional heat. The size and dispersion microclimate.3 To assess frozen contamination, of the asperities — each ranging in height from however, accurate runway-surface temperature about a micrometer to a millimeter — and the information is crucial.4 adhesive characteristics of the frozen contamina- Air temperature at an airport can vary tion also play a key role. significantly from runway-surface temperature, The mechanical tendencies of frozen con- especially when there are few clouds and the taminants — for example, that ice easily will wind is light. In this situation, radiation be- creep6 under load — are governed by the mag- comes the dominant factor governing the local nitude of the homologous temperature of each thermal state. specific contaminant. Homologous temperature
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and mechanical characteristics of fro- “Black ice” on runways, zen contamination, which change due closely resembling liquid to factors such as runway maintenance water, surprises unwary pilots. and metamorphism — transformations occurring between forms of frozen wa- ter, such as snow to granular ice, caused by a change of external pressure such as from tires — temperature, vapor pres- sure and ice-particle geometry.
Contact-Free Observations The temperature of most materials can be measured by direct physical contact between the material and a heat- © Reinhard Mook conducting probe, which senses temper- ature increases/decreases as changes of is the ratio of its absolute tempera- this coefficient of friction depends liquid volume or deformation of metal ture to its melting-point temperature, increasingly on sliding velocity and load. or the changes in voltage output from expressed by scientists using kelvins. Specifically, the water volume from fric- a thermocouple or electrical resistance Expressed in METAR temperatures, tional melting increases as a function of thermometer. The surface temperature ice at minus 30 degrees C (minus 22 the square root of the sliding velocity. of a runway profile — a line designated degrees F) has a relatively warm ho- There are exceptions. For example, for measurements where wheel braking mologous temperature of 0.89, its 243 at a low temperature, a low aircraft typically occurs — cannot be measured K absolute temperature divided by its braking coefficient of friction may occur conventionally. Instead, other methods 273 K melting-point temperature. By if frozen contamination on the runway have been developed. For example, the comparison, the homologous tempera- surface has been “polished” by the verti- density of infrared radiation emitted ture of titanium at minus 30 degrees C cal skipping and horizontal movements from the runway surface depends on is 0.13. of drifting particles of ice or when the its temperature. So the temperature of One counterintuitive factor is that tire lifts because of an air-snow mixture a large area may be derived indirectly if the frozen contamination is near its in an intermediate layer. by moving an infrared radiation sensor melting-point temperature, the aircraft Wet snow on ice may create a com- above the runway profile. braking coefficient of friction decreases plex, but weak, pattern of transmitting To be reliable and valuable at the — that is, braking action becomes shear stress during braking. The reason microtexture level, however, measur- worse — with increasing load. Thus, is that snowflakes contain liquid water ing temperature by sensing infrared the tires of a heavy aircraft may gener- — and near the sea, they may contain radiation — whether at one spot over ate less friction than those of a much dissolved salt — promoting slippery the runway or all along the runway lighter aircraft. conditions. At 0 degrees C, at least 10 profile — requires excluding the infra- Pilots also should be aware that the percent of the weight of snow is liquid red radiation from extraneous sources. aircraft braking coefficient of friction water, maybe more depending on local Surface temperatures of a runway pro- decreases significantly in relation to in- topography and the resultant vertical file can be recorded without erroneous creasing amounts of liquid water on top, air movement in clouds. By definition, readings by eliminating sources such as inside and at the base layer of the frozen at least 30 percent of the weight of slush radiation from the measuring instru- contaminant on the runway due to melt- is liquid water. So the squeezing of such ment, floodlights, warm exhaust from ing, which submerges the ice asperities frozen contaminants under aircraft vehicles or blowing snow between the and — by water lubrication — reduces tires contributes significantly to water sensor and the surface. their ability to transmit shear stress. As lubrication and slipperiness. Adding The method currently used for the volume of liquid water increases, complexity are the dynamic crystalline taking runway-surface temperature
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readings is to install electrical resistance Scientists for decades have been able vapor is saturated. In the early 1950s, thermometers into the concrete or to calculate the amount of dew or hoar one scientist calculated that for snow at asphalt. Besides confining each read- frost that will be deposited at the Earth’s 0 degrees C, the onset of melting does ing to a fixed site only — not taking surface from the net radiation, the flow of not occur at standard sea-level pressure into account the thermal and micro- heat and air temperature, without directly until the air temperature exceeds 2.5 meteorological differences along the measuring the surface temperature.7 To degrees C (36.5 degrees F) at a relative runway pavement — this method has routinely monitor all the variables would humidity of 60 percent or 4.2 degrees C other inherent problems. Readings are be too complex and impractical for rou- (39.6 degrees F) at 40 percent because dependent on heat flow through the tine airport operations, but the underly- of the latent heat of evaporating water.8 runway pavement and, in some cases, ing principles are valuable. Frozen dew or hoar frost reduce through the layers of frozen contamina- In particular, when the radiation runway friction by water lubrication. If tion. Therefore, the indicated tem- balance between the ground and the freezing is not a factor, dew forms when peratures on these thermometers are atmosphere is negative — as on clear the dew-point temperature adjacent to damped, lagging behind actual condi- winter nights — the runway pavement the runway surface is warmer than the tions. Several minutes elapse on average cools by radiation deficit with the rate surface. When conditions conducive before they reliably indicate a surface- affected by the cooling of the adjacent to freezing are involved, however, the temperature change. air and the heat conducted from deep frost-point temperature becomes most inside the pavement to the cooling relevant. Because the saturation vapor Ground/Air Freezing runway surface. The air transfers heat pressure in relation to solid water — ice Because the ground is the major trans- to the radiation-emitting surface, and if — is lower than in relation to liquid wa- former of heat, from absorbed radia- formed, dew and freezing dew or hoar ter, the saturation vapor pressure can be tion to heat and from heat to emitted frost contribute by releasing heat. The reached, causing frost formation despite radiation, the microclimate with the resulting temperature inversion in the a seemingly wide difference between the most extreme temperature fluctua- air layer adjacent to the runway surface METAR air temperature and dew point, tions actually is found at, or close to, easily may produce a surface 10 K (10 which is reported in METARs even at the microtexture of the runway surface. degrees C, 18 degrees F) colder than the temperatures below freezing.9 Within this boundary layer of air, just airport’s METAR air temperature. fractions of a millimeter in thickness, Dew strongly contributes to melting Predicting Frost and Worse vertical temperature gradients equiva- because the heat released by one unit A practical guideline for flight crews is lent to several thousand kelvins per of dew theoretically can melt 7.5 units that the frost point will be 1 degree C meter are common. of ice at 0 degrees C. But, at this air (1.8 degrees F) warmer than the airport’s Many aspects of heat flow that in- temperature, ice melts only if the water reported dew point while the airport’s fluence changes in runway-surface tem- © Ole M. Rambech/Svalbard Airport Longyear perature have to be considered. These include absorbed and emitted solar/ terrestrial radiation, sensible heat flow Reinhard Mook’s tire-temperature — what people describe as temperature readings from a Boeing 737-400 changes — in the air due to convec- factored into slippery-runway analyses. tion and shear stress turbulence, latent heat within or released by water vapor, heat absorbed by melting or released by freezing, heat conducted inside the pavement and heat content in the layers of frozen contamination. Other factors also may be significant, such as the heat content in freezing rain and the lateral heat transfer by air. www.flightsafety.org | AeroSafetyWorld | October 2007 | 27 FlightOPS
surface temperature is minus 10 degrees F) between METAR air temperature 5. The following sources explain these factors. C (14 degrees F), 2 degrees C (3.6 de- and runway-surface temperature. Bäurle, L. “Sliding Friction of Polyethylene grees F) warmer at minus 20 degrees C In another scenario, lateral heat on Snow and Ice.” Dissertation no. 16517 (2006), Swiss Federal Institute of (minus 4 degrees F) and 3 degrees C (5.4 transfer by air at temperatures above Technology, Zurich. Buhl, D.; Fauve, M.; degrees F) warmer at minus 30 degrees freezing, with the runway surface covered Rhyner, H. “The kinetic friction of polyeth- C (minus 22 degrees F). That means by frozen contamination, may cause the ylene on snow: The influence of the snow that a METAR showing a 1 degree C air to cool. Since frozen contamination temperature and the load.” Cold Regions temperature–dew point spread with a by definition cannot exceed 0 degrees C, Science and Technology, Volume 33 (2001), surface temperature of minus 10 degrees dew formation and the melting process 133–140. Colbeck, S.C. “The kinetic fric- tion of snow.” Journal of Glaciology, Volume C already is a saturated vapor condition then may cause an extremely slippery 34 (no. 116, 1988), 78–86. Eriksson, with respect to ice — so flight crews runway despite a METAR air temperature R.; Nupen, W. “Friction of Runners on should expect frost on the runway. In well above freezing. ● Snow and Ice.” U.S. Army Snow, Ice and fact, a runway at minus 10 degrees C Reinhard Mook, Ph.D., who retired in 2006 Permafrost Establishment no. 44 (trans- might be coated with ice. as a professor at the University of Tromsø in lated). U.S. Defense Technical Information In the case of solar radiation or Norway, is an independent consultant and Center. April 1955. Kuriowa, D. “A Study of Ice Sintering.” Tellus, Volume 13 (1961), warm nocturnal clouds above a cool researcher whose main interest is meteorological 252–259. Kuriowa D. “The kinetic friction ground, both the runway pavement and phenomena near the ground, including practical applications ranging from atmospheric effects on snow and ice.” Journal of Glaciology, the air gain heat by surplus radiation. on technology to demographic effects. Mook Volume 19 (no. 81, 1977), 141–152. On an uncontaminated runway surface, received his doctorate from the University of Oksanen, P.; Keinonen, J. “The mechanism the temperature may exceed the adjacent Innsbruck, Austria, after conducting research of friction of ice.” Wear, Volume 78 (1982), air temperature. For example, even dur- on radiation and heat data from Antarctica 315–324. Persson, B.N.J. Sliding Friction: Physical Principles and Applications, 2000, ing summer in the Arctic, the runway- in 1961. His research in 2004 and 2005 was Springer Verlag, Berlin. Petrenko, V.F.; surface temperature may be 20 K (20 conducted with encouragement from the staff of Svalbard Airport Longyear and Avinor, the Colbeck, S.C. “Generation of electric fields degrees C, 36 degrees F) warmer while owner and operator. by ice and snow friction.” Journal of Applied METARs report the air temperature as Physics, Volume 77 (no. 9, 1995), 4518– freezing; far higher runway-surface tem- Notes 4521. Salm, B. “Mechanical Properties of peratures may occur at lower latitudes. S n ow.” Reviews of Geophysics and Space 1. Sintering is molecular-level bonding/fu- Physics, American Geophysical Union, Such transfers of heat to frozen con- sion that can occur within clusters of snow Volume 20 (no. 1, 1982), 1–19. Sinha, N.K. tamination on the runway surface typi- grains, causing them to freeze into larger “Grain Boundary Sliding in Polycrystalline cally cause evaporation and warming to snow crystals; the process also occurs in Ice.” Journal of Glaciology, Volume 2 (no. 85, 0 degrees C followed by melting. Solar ice and other aggregates. 1979), 457–473. radiation through a transparent layer of 2. In micrometeorology, scientists typically 6. Creep — most familiar in the slow move- ice can cause melting that begins from study weather-related processes on scales ment of glaciers — also occurs in thin lay- the bottom of the layer. In contrast, from a millimeter or less above ground ers of ice; the cause is mutual displacement frozen contamination absorbing heat at level to heights of hundreds of meters — of ice crystals in response to shear stress. its upper surface can attain 0 degrees C focusing, for example, on the air-ground 7. Hofmann, G. Die Thermodynamik and melt beginning from the top layer, exchange of heat and moisture at the der Taubildung [Thermodynamics of shallow boundary layer of air next to the although the METAR air temperature is Dew Formation]. Berichte Deutscher ground at a specific site. Wetterdienst, Volume 18 (no. 3, 1955), well below freezing. Offenbach, Germany. Conversely, in conditions of warm 3. Cannegieter, H.G. “The History of the International Meteorological Organization air and little water vapor, with minimal 8. Müller, H.G. “Zur Wärmebilanz der 1872–1951,” Annalen der Meteorologie Schneedecke [On the Heat Balance of or zero solar radiation, evaporation [Annals of Meteorology], New Series 1 (1953). Snow Cover].” Meteorologische Rundschau. from a wet runway surface — combined Volume 6 (1953), 140–143. 4. Lande, K. “Winter Operations and with the radiation deficit — may result Friction Measurements.” In proceedings 9. Saturation vapor pressure, the maximum in ice forming on the runway surface of the 38th Annual International Society water vapor pressure that can exist in air despite an apparently large difference of of Air Safety Investigators Seminar, at a given temperature, increases strongly 10 K to 15 K (10 degrees C, 27 degrees Aug. 27–30, 2007, Singapore. with a rise in air temperature.
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relatively small but disparate response The proposed additions to Federal Aviation was received by the U.S. Federal Avia- Regulations Part 25.1419, Ice Protection, would tion Administration (FAA) to proposed include a requirement for continuous operation new certification standards intended to of the IPS after initial activation, a system that Aensure timely activation of airframe ice protec- automatically cycles the IPS or an ice-detection tion systems (IPSs).1 system that alerts the flight crew each time IPS The proposal, issued in April 2007, would activation is required. require manufacturers seeking icing certification The FAA said that the proposal partially ad- of new transport category airplanes to provide dresses recommendations by the U.S. National one of the following methods for detecting Transportation Safety Board (NTSB) stemming airframe icing and activating the IPS: from the investigations of ice-related accidents involving an ATR 72 in October 1994 and an • “A primary ice-detection system that au- Embraer Brasilia in January 1997.2,3 The NTSB tomatically activates the IPS or alerts the recommendations included a “means for flight flight crew to activate the IPS; crews to positively determine when they are • “A definition [in the airplane flight manual in icing conditions that exceed the limits for (AFM)] of visual cues for recognition of aircraft certification” and “revision of manuals the first sign of ice accretion on a specified and training [procedures] to emphasize that surface, combined with an advisory ice- leading-edge deicing boots should be activated detection system that alerts the flight crew as soon as the airplane enters icing conditions.” to activate the IPS; or, The proposal is based on recommendations by an Aviation Rulemaking Advisory Committee • “Identification [in the AFM] of conditions working group that was formed after the ATR conducive to airframe icing as defined by 72 accident to review in-flight icing safety issues. an appropriate static or total air tempera- The FAA said that the working group found ture and visible moisture for use by the subsequent accidents and incidents in which “the flight crew to activate the IPS.” flight crew was either completely unaware of ice Comments Vary on Ice-Protection Proposal BY MARK LACAGNINA
U.S. certification standards would require new equipment and operating procedures to combat ice-related accidents.
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accretion on the airframe or was aware the proposal but chided the FAA for Similarly, Transport Canada said of ice accretion but judged that it was not not having taken action sooner. that alternatives to ice-detection significant enough to warrant operation Several comments opposed the systems should either not be allowed of the IPS.” requirements for ice detectors. Charter or be allowed only in airplanes that The FAA received 15 comments on aircraft operator Ameriflight said that an have been identified as having “a lower the proposal before the public comment ice detector should be required only if it risk of icing-related incidents and period ended on July 25. The following is shown that the flight crew cannot vi- accidents.” are partial summaries of the comments: sually detect ice on a particular airplane. The founder of Innovative Safety The NTSB said that although it sup- “It is our experience that the onset of ic- Systems International said that requir- ports the proposed requirements, the ing is easily detectable … in the corners ing ice detectors would be folly. “They scope should be expanded to include of the windshield, on windshield wiper provide warning after the fact,” he said. airplanes that already are certified for arms, etc.,” the company said. “They are fragile [and] unreliable.” flight in icing conditions and that cur- A similar comment was filed by a He told the FAA that it should simply rent AFM recommendations to delay former U.S. Air Force pilot, who said, specify the requirement and allow the activation of deicing boots until a spe- “Each airplane will accumulate ice first industry to design systems that meet the cific amount of ice accumulates should on a certain part, and the pilots know intent of the requirement. be revised. Such recommendations are where to look for the first indication of Aerodynamic performance based, in part, on the belief that prema- ice buildup.” monitoring systems were alternatives ture activation of deicing boots might Ameriflight also argued against proposed by both the Regional Airline cause ice to form a bridge over the boots, automatic activation of the IPS at Association and by Marinvent Corp. rendering them ineffective. “Ice bridging the first sign of ice. “Ice is only par- The systems “directly measure the deg- does not occur on modern airplanes,” tially shed [on initial activation],” the radation of airfoil performance caused NTSB said. “The IPS should be acti- company said. “The remainder on the by the roughness and profile changes vated as soon as the airplane enters icing boot results in ‘islands’ of ice that are induced by the contamination of the conditions.” sufficiently well-attached that they are airfoil,” Marinvent said, noting that Comments filed for Airbus, the Air not readily shed on successive cycles degradation of airfoil performance is Line Pilots Association International, and provide a rough surface onto which “the root cause of icing accidents.” BAE Systems, Boeing Commercial additional ice accumulates more readily The FAA will consider the public Airplanes and Bombardier generally than upon a smooth boot surface.” comments as it progresses toward pub- supported the proposal. Automatic IPS operation “at inoppor- lication of final rules or withdrawal of Boeing recommended one revision: tune times could actually decrease safety the proposal. ● adding words to specify that continuous by causing pre-existing ice accumulations Notes operation of the IPS is required “while to be shed into engine inlets, undesired 1. The notice of proposed rulemaking and the the aircraft remains in icing conditions.” drawdown of engine bleed air, excess public comments are available by searching Without this clarification, the IPS would electrical load, etc.,” Ameriflight said. for docket no. 27654 at
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Airing It Out Studies have found no link between cabin air quality and health problems, but some crewmembers and passengers say those studies are wrong.
BY LINDA WERFELMAN
irplane crewmembers have complained fluid or other sources that have permeated the for years about the quality of air on the airplane environment, resulting in nausea and flight deck and in the cabin. Its un- respiratory or neurological problems. comfortably low humidity leaves them The environment of most commercial jet Asusceptible to dry skin, eyes and nasal passages, airplanes, like that of an office building, is a and the dry environment — together with recir- mixture of outside air and recirculated air (Fig- culated cabin air — has sometimes been blamed ure 1, p. 32). An environmental control system for helping to spread colds and other conta- (ECS) maintains temperature, humidity, cabin gious diseases. Less frequently, complaints have pressure and ventilation; it also filters harmful centered on fumes from engine oil, hydraulic contaminants to limit their introduction into
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Dominant Cabin Airflow Pattern in Transport-Category Aircraft percent said they had experienced an “irritated, stuffy or runny nose.”2
Air ducted from the air The report, noting discussions of the mix chamber enters health aspects of air recirculation, said that the the cabin near the ceiling. survey also found that pilots of SAS McDon- nell Douglas DC-9s — in which there was no recirculated air — experienced colds and other respiratory ailments at about the same frequency as pilots of airplane models with air recirculation. A 2002 review of studies of the effects of cabin environment on the health of flight atten- dants found that “dryness symptoms attributable to low humidity” were among the flight atten- 3 Some cabin air is vented dants’ most frequent complaints. overboard; some cabin air These complaints typically are not associated is ltered for recirculation Cabin air (except in systems that use Cabin air with illness, said Anthony Evans, M.D., chief of lters 100% outside air). lters the aviation medicine section at the Internation- al Civil Aviation Organization (ICAO). Source: Derived from an illustration provided by Pall Corp. “Low humidity is related to comfort rather Figure 1 than ill health; humidity levels found on aircraft [have] been demonstrated as not sufficient to the environment (see “Cabin Climate Control,” cause clinical dehydration,” Evans said. p. 34). An ECS cannot eliminate all potential A 2007 study discussed an unexpected fac- problems, however, and many issues have not tor: The interaction between oils in human skin yet been adequately addressed, the U.S. National and ozone in the cabin may produce chemical Research Council (NRC) said in a 2002 report.1 byproducts that worsen dry eyes and skin and “Environmental factors, including air con- contribute to headache and nasal irritation. taminants, can be responsible for some of the Some airplanes have ozone-destroying sub- numerous complaints of acute and chronic health stances in their ventilation systems; on airplanes effects in cabin crew and passengers,” the NRC that do not, the ozone levels can exceed those report said. Nevertheless, the report added, “The recorded in large cities on smoggy days, the complaints tend to be so broad and nonspecific study said.4 and can have so many causes that it is difficult to Cabin air quality is the subject of several define or discern a precise illness or syndrome.” ongoing studies, including one being con- ducted for the American Society of Heating, Dry Air and Dirt Refrigerating and Air-Conditioning Engineers A 2006 report based on a survey, conducted (ASHRAE). That study is designed to survey in 2000, of more than 600 SAS Scandinavian passengers on 160 flights about their percep- Airlines System pilots found that complaints tions of cabin air quality and then to scientifi- about the flight deck environment were com- cally evaluate the air quality using on-board mon and differed somewhat among different monitoring instruments. An early phase of the models of airplanes. Overall, 53 percent of pilots research found that overall cabin air quality complained of dry air, and 48 percent said that was considered “adequate” by passengers on they were bothered by dust and dirt. When four U.S. domestic flights.5 questioned about medical symptoms, 10 percent The survey coincides with ASHRAE’s effort reported “dry or flushed facial skin,” and 9 to develop standards for airplane air quality —
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in terms of temperature, humidity and ventila- Many specialists say that under routine operating tion. The standards are expected to be published conditions, there are no problems with air quality. late in 2007.6 “The air quality is good on board aircraft in Quay Snyder, M.D., president and CEO of comparison to that found in buildings or outside Virtual Flight Surgeons, an aeromedical consult- in a city, for example, and the filters used for ing firm, and an associate aeromedical adviser recirculation are highly efficient at removing for the Air Line Pilots Association, Interna- viruses and bacteria,” Evans said. tional, said that the physicians in his office Russell B. Rayman, M.D., executive director “very, very rarely hear anything from the pilots of the Aerospace Medical Association, agreed.7 regarding cabin air quality. … We occasionally “Everything that makes an airplane run hear about low humidity from pilots with ongo- is toxic — the fuel, the hydraulics — but if an ing sinus problems, primarily in the context of aircraft is properly functioning, there is no prob- inquiries regarding strategies to deal with it, lem [with air quality],” he said. rather than complaints.” The NRC said that research attempts to col- The NRC said that although a variety of lect data on exposure to on-board contaminants studies have shown that upper respiratory have not presented a complete picture. infections and other contagious diseases are “The data represent only a small number of passed from one person to another in air- flights, and the studies have varied considerably planes, the ECS apparently is not a factor in in their sampling strategies, the environmental transmission. Instead, the most important factors monitored and the measurement meth- transmission factors are density of airplane oc- ods used,” the NRC said. “Consequently, cabin cupants and their nearness to one another, the air quality under routine conditions has not NRC said. been well characterized.” Nevertheless, the NRC said that healthy Contaminants people probably would not be adversely affected Sometimes, when airplane systems malfunction, by exposure to reduced air pressure and elevated complaints may involve not dry air but contami- ozone levels. nated air. Although the NRC said that “no published “The air quality “Although the ECS is designed to minimize studies describe quantitative measurements of air the concentrations of contaminants in the cabin, quality under abnormal operating conditions,” is good on contaminant exposures do occur,” the NRC said. reports by accident/incident investigative boards board aircraft in “They can originate outside the aircraft, inside in a number of countries discuss incidents in the aircraft, and in the ECS itself.” which oil fumes or hydraulic fumes have been comparison to that The NRC and other researchers define two introduced into the airplane by an ECS. types of contaminant exposures: For example, a report by the Swedish Ac- found in buildings • Those that occur during routine oper- cident Investigation Board (SHK) described a or outside in a city.” ating conditions, such as when ozone Nov. 12, 1999, incident in which the captain enters an airplane along with ventilation and copilot of a Braathens Malmö Aviation air during flight at high altitudes, and BAE Systems BAe 146-200 were temporarily when chemical residues from cleaning incapacitated during a descent from 15,000 ft in substances and other materials linger in preparation for landing at Malmö after a flight an airplane; and, from Stockholm.8 • Those that occur during abnormal condi- The SHK said that the probable cause of the tions, such as when engine oil, hydraulic incident — in which none of the 73 people in fluid, deicing fluid and other substances the airplane was injured and the airplane was enter an ECS and are then dispersed not damaged — was “the pilots becoming tem- throughout the airplane. porarily affected by probably polluted cabin air.” www.flightsafety.org | AeroSafetyWorld | October 2007 | 33 aviationmedicine
Investigators were unable to identify the source In another incident, the U.K. Air Acci- of the pollution, however. dents Investigation Branch (AAIB) said that The report cited a series of ailments experi- on several days in November 2004, the flight enced by the crew not only during the incident crew and cabin crew of a Boeing 757 had a flight, which was the last of three one-hour variety of symptoms on different flights be- flights that day, but also during the two prior tween London Heathrow Airport and several flights. Those ailments included the purser’s European cities.9 “unpleasant feeling of fainting” during the first “The aircraft experienced several incidents, flight and a flight attendant’s “odd pressure in on different flights, of fumes in the cockpit and the head, nasal itching and ear pain” during cabin, and in some cases, this produced symp- the second flight, when the purser and another toms in the flight and cabin crew,” the AAIB flight attendant also reported discomfort. Dur- report said. “Although evidence was found of ing the third flight, the captain and the purser leaking hydraulic fluid having migrated inside a briefly detected a burning odor, followed by bleed air supply duct, the various investigations “more pronounced” discomfort experienced by failed to definitively establish if this was the all cabin crewmembers; later, the captain was source of the fumes.” dizzy and both flight crewmembers became The report cited “numerous other reports nauseous. After several minutes of breathing of oil smells in the cockpit and/or cabin of oxygen, they conducted a normal approach and the Boeing 757” and said that the fumes in landing “without problems,” the report said. the November 2004 incidents — described by crewmembers as “warm, sweet … but slightly burnt” and similar to “oily sewage” — might Cabin Climate Control have indicated that the hydraulic fluid leak was unrelated. ommercial jet airplanes typically have an environmental control The symptoms experienced by the crew dur- system (ECS) to establish a safe, comfortable environment by ing three days of problems included the captain’s regulating cabin air pressure, air temperature and humidity and C sensation of being “a bit spacey” and feeling “a limiting the introduction of contaminants. The ECS maintains cabin air pressure at no less than the atmo- little unwell,” the first officer’s “buzzy head and spheric pressure at 8,000 ft — the limit set by civil aviation authori- body” and several cabin crewmembers’ sore ties. In most airplanes, the ECS uses a combination of engine bleed throats, the report said. air — outside air brought into the system through the engines — and The report said that, of the various reports recirculated air — cabin air that is filtered and redistributed through of oil smells, “some of these events have been the airplane. Some airplanes, such as the McDonnell Douglas DC-9 and the result of genuine oil leaks from the engine the Boeing 787, use no recirculated air. Outside air enters the jet engine compressors, where it is warmed or [auxiliary power unit] compressor oil seals. as it becomes pressurized, then cooled by the engine’s heat exchang- In other cases, no definite source of the fumes ers and the air conditioning units. Cooled air is mixed with a similar could be identified. However, service experience amount of filtered air from the cabin and then enters the cabin shows that overfilling the engines with oil can through overhead outlets. The air flows through the cabin in a circular produce fumes in the aircraft interior.” pattern before it is either vented overboard or filtered to remove The AAIB said that after a previous incident nearly all particles, including bacteria, viruses and liquid droplets of some contaminants, before it is recirculated. 1 involving another 757 belonging to the same op- The recirculated air contains slightly more humidity; some air- erator, that operator took “extensive measures to planes also are equipped with humidifying systems. ensure that the engine oil is serviced correctly.” — LW In this incident, there was no indication that the Note engines were overfilled with oil. 1. Boeing Commercial Airplanes. Cabin Air Systems.
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the most commonly used description, June 2007 that she still experiences these and Environmental Medicine Volume ‘smelly’ since its introduction into symptoms — 10 years after she stopped 77 (August 2006): 832–837. The survey passenger service in the mid-1980s.” flying because of health problems and questioned pilots of Boeing 737-600s and Cabin air quality was a “persistent eight years after losing medical certifica- 767-300s, and McDonnell Douglas DC-9s, problem” since the early 1990s, with tion. Michaelis, now a researcher for the MD-80s and MD-90s. periodic complaints of oil fumes in Global Cabin Air Quality Executive, said 3. Nagda, Niren L.; Koontz, Michael D. the cabin. As a result, the report said, that she believes the symptoms result “Review of Studies on Flight Attendant a number of BAe 146 crewmembers from repeated exposure to an engine oil Health and Comfort in Airliner Cabins.” experienced an “occupational health additive called tricresyl phosphate.12 Aviation, Space, and Environmental effect” that caused some to stop “I am well aware of many other Medicine Volume 74 (February 2003): flying.10 pilots and flight attendants in Australia 101–109. In 2001, after several incidents experiencing almost identical effects 4. American Chemical Society. Skin involving the partial incapacitation and similarly no longer able to fly, in Oil–Ozone Interactions Worsen Air of flight crewmembers, the U.K. Civil most cases,” she said. “I am also aware Quality In Airplanes.
Technology Can Reduce Runway Mishaps
By John W. Douglass
ven a quick scan of aviation-related several government agencies. (See InfoScan, news over the last few months reveals p. 54.) several high-profile reports of near- The Next Generation Air Transportation collisions on runways. Data show that System, or NextGen, includes advanced tech- seriousE incidents are more frequent as U.S. nology that, along with enhanced training and airports and skies become more crowded and awareness, can go a long way toward dramati- passenger numbers climb toward unprec- cally increasing runway safety. edented levels. It is clear the no-end-in-sight increase The news underscores the importance of in demand for air travel is a major factor in aggressively pursuing the transformation runway incidents. A 2000 study by Transport and modernization of the U.S. air transpor- Canada, which included U.S. Federal Avia- tation system that is under way by the Joint tion Administration (FAA) data, found that a Planning and Development Office, authorized 20 percent increase in traffic volume repre- by the U.S. Congress to coordinate a major sents a 140 percent jump in runway incursion air traffic control system upgrade involving potential. Building on the excellent work of the ADS-B moving map displays will cut through bad visibility Commercial Aviation Safety Team (CAST), the FAA and aviation community responded and provide pilots not only with their position on the to the recent events with swift and strong airport grounds, but also with information about all other ground measures, instituting a number of immediate changes to make runways safer. They include traffic and the positions of other aircraft flying near the runways. thorough reviews at the 20 airports with the
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greatest history of problems or risk factors, guide pilots around the often confusing airport improved procedures for pilots, and expedited environment. The displays will cut through bad lighting and signage upgrades at dozens of visibility and provide pilots not only with their airports. These actions are excellent steps position on the airport grounds, but also with that directly improve situational awareness information about all other ground traffic and and should lead seamlessly into long-term the positions of other aircraft flying near the fixes. runways. Full implementation of this capability It is critical that we remain diligent in pur- may take years. suing those long-term fixes within NextGen. In the interim, we must maximize the use of This sweeping transformation of the air traffic other existing technologies, such as own-ship control system holds extremely promising moving map displays, to provide crews with technologies for both flight crews and control- enhanced situational awareness, improved alert- lers that could make runway incidents a thing ing and reduced distractions. These steps will of the past. go a long way toward making airport operations This is not something in the distant safer. future — it is already in the works. The FAA It is very important that we do not see initial recently awarded a contract for one of the incremental advancements like the ADS-B building blocks of NextGen, the automatic contract and conclude that we’ve solved all our dependent surveillance-broadcast (ADS-B) problems. system. The US$1.8 billion contract, which Right now, NextGen represents tremen- went to a team led by ITT Corp., calls for dous potential. NextGen will be a remark- development and deployment of ADS-B over able accomplishment for the United States, the next three years, with full implementation adding desperately needed capacity to the by 2013. system while making air travel safer in the ADS-B has proven itself effective in early skies as well as on the ground. But we must implementation in Alaska under the Capstone move forward aggressively to ensure its John W. Douglass will program, where its use has cut the accident implementation. retire next month after rate in half. So clearly, ADS-B proves capacity This will require strong and consistent nine years as president and enhancements and safety enhancements can go advocacy from the aviation community to CEO of the Aerospace hand-in-hand. ensure that leaders make the investment and Industries Association. ADS-B will be a huge leap forward because commitment to fully it incorporates global positioning system (GPS) implement NextGen, technology into the air transportation system both in the near-term for the first time. and long-term. We ADS-B uses GPS to provide quick and ac- must take advan- curate aircraft position information, a major tage of all the safety upgrade from the decades-old radar-based capabilities provided system in use today. The information is much by ADS-B and other more precise, and can provide additional capacity-increasing data on weather and traffic to both pilots and building blocks. As air traffic controllers. The system can vastly NextGen planning increase situational awareness both in the air and implementation and on the ground, which can make it the continue, we must first line of defense against runway ensure that the safety accidents. improvements remain When implemented, ADS-B will enable a priority central to full-capability moving map displays to help the plan. ● www.flightsafety.org | AeroSafetyWorld | October 2007 | 37 CABinsafety Beyond Passenger Service
Business jet accident shows the value of exceeding regulatory requirements for flight attendants.
By Wayne Rosenkrans
© Chris Sorensen Photography
ome operators of corporate, charter and into sharp focus the value of a flight attendant private flights in business jets use flight in corporate/charter operations (ASW, 3/07, p. attendants to perform safety and service 30).2 The aircraft was destroyed by crash forces duties when this is not required by aviation and postcrash fire after colliding with vehicles Sregulations.1 Other operators say that a flight on a freeway and a warehouse. The flight crew attendant would not be appropriate in the context received serious injuries. The nine passengers, of their overall safety strategy — and they instead including one “cabin aide” — a customer service train passengers to cope with cabin emergencies representative provided by the operator — re- or depend entirely on the flight crew. Making ceived minor injuries. someone responsible only for service-related One of the U.S. National Transportation Safety duties in the cabin, however, falls short of the best Board (NTSB) findings said, “The cabin aide did safety practices currently recommended. not perform a seat belt compliance check before Circumstances of the February 2005 runway the accident flight, which resulted in two pas- overrun at Teterboro, New Jersey, U.S., by a sengers being unrestrained during the accident chartered Bombardier Challenger 600 brought sequence.” Another said, “The cabin aide’s training
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did not adequately prepare her to perform the du- absolutely no safety training,” said Jason Fedok, ties with which she was tasked, including opening the NTSB survival factors investigator for this ac- the main cabin door during emergencies.” One of cident. The NTSB has watched the airline industry, the accident report’s four safety recommendations over a period of decades, shift the balance of in- focused on the risk of passenger confusion about flight service from cabin crews focusing too much any cabin employee’s role and qualifications.3 on passenger comfort issues to currently putting Several passengers — because of differences safety first as safety professionals. “The same compared with flying on their own company’s evolution needs to happen in the corporate/charter Challenger — were surprised to be greeted by a world,” Marshall said. person who the NTSB found was “dressed in a crewmember-appearing uniform,” served them Not As Expected beverages and occupied the cockpit jump seat for Flight Safety Foundation safety auditors discour- takeoff but did not conduct a pre-takeoff safety age the use of cabin aides for one main reason. briefing.4 The passengers assumed that the cabin “You cannot tell passengers that the person aide was a flight attendant trained to conduct serving them is less than fully qualified — that Defense of an evacuation, but — after the airplane stopped would only confuse them,” says Darol Holsman, crewmembers, moving — they initially could not find her, they FSF manager, safety audits. The same principle passengers or the heard no evacuation commands, and they heard applies to substituting in this role any pilot or aircraft against no answer when they asked her how to open maintenance technician who has not been cross- unexpected threats the main cabin door. A separate survival factors trained as a flight attendant. may require training report also cited the cabin aide’s departure from Holsman said that he has been disappointed tailored to the aircraft and accident scene before accounting lately by some corporations’ reluctance — in confined spaces. for everyone on board.5 spite of FSF awareness “We were concerned when we heard that efforts — to volun- passengers were thrown out of their seats and tarily integrate a flight were unable to locate seat belts on the divan. We attendant into the asked our regional investigators to notify us if crew complement of they find those problems in future accidents be- the larger business jets cause we would like to investigate and document for the sake of passen- that type of information,” said Nora Marshall, ger safety. Corporate/ chief, NTSB Survival Factors Division. “If there charter operators typi- is someone on board the aircraft who could be cally consider a flight perceived as a trained crewmember, that person attendant only if they should have proper training. The NTSB did not fly something like a ask for cabin attendants to be required; it said Challenger 600, 601, that if on board, they should be trained and ef- 604 or Global Express; fective for emergencies.” a Gulfstream GIV/4 or “When there is a cabin aide on board, flight GV/450/550; or a Das- crews may be tempted to delegate some of their sault Falcon 50, 2000 safety-related responsibilities — such as the safety or 900, he said. briefing — to this ‘crewmember’ when, in fact, The FSF audit
he or she may only be a caterer or server with team has promoted © Chris Photography Sorensen
www.flightsafety.org | AeroSafetyWorld | October 2007 | 39 CABinsafety
hands-on cabin emergency training initially and every two years, first aid training and for frequent-flier corporate executives aircraft-surface contamination training].” especially when a flight attendant can- Flight attendant training already is a major not be assigned. “But what is lacking part of the U.S. National Business Aviation then is any guarantee that those who Association (NBAA) Standards of Excellence © Chris Photography Sorensen receive training have the discipline in in Business Aviation (SEBA) program, which an emergency to get people off the air- encourages continuing education within the plane in a hurry,” Holsman said. “More business aviation community. It establishes a set than 90 percent of pilots we interview of common expectations between flight atten- have a high level of confidence that dants and aviation department pilot-managers, the flight attendant could evacuate the says Jay Evans, director, operations, and staff passengers if something happened to committee liaison to the NBAA Flight Atten- the flight crew.” dants Committee. At the global level, a voluntary The NBAA has promoted the voluntary use code of best practices, the International of flight attendants by awarding them a total of Standard for Business Aircraft Opera- 261 scholarships since 2000, identifying train- tions (IS-BAO), positively influences ing organizations and attracting flight attendants operators’ attitudes about the voluntary to business aviation. Flight attendants also have use of flight attendants, according to been strongly encouraged to complete the NBAA Peter Ingleton, director, International certified aviation manager program, Evans said. Civil Aviation Organization liaison, Endorsement of professional training of of the International Business Aviation flight attendants has permeated NBAA activi- Confidence gained Council. The IS-BAO says, “The minimum num- ties, he said. “The NBAA Management Guide boarding a life raft ber of cabin crewmembers shall be in accordance also emphasizes that a flight attendant is aboard from the water extends with national requirements” and operators “shall for safety — ensuring that the flight crew is to other aspects of ensure that each cabin crewmember has fulfilled briefed properly, exits are managed properly, coping with a ditching. the requirement of the operator’s ground and emergency equipment is prepared, and the flight training program [with initial and annual passengers briefed and ready to go,” Evans said. training covering aircraft type training, safety pro- “In so many instances, we know that a properly cedures training, emergency procedures training trained flight attendant responded properly and saved lives. Being there and handling the situa-
© Chris Sorensen Photography tion made a difference.”
One Person’s Commitment Voluntarily implementing a three-person crew in a business jet can begin with just one man- ager’s commitment to the value of having a flight attendant, says Doug Schwartz, manager, Global Aviation Services at ConocoPhillips. His company takes the position that within the logistical confines of the size of the airplane, the minimum crew for a business jet with a flat floor and wide cabin is two pilots and a flight atten- Hands-on experience using the canopy dant. Logistics come into play because in some and other life-raft equipment saves time airplane types, there is no room in a full cabin and reduces risks in actual events. for a flight attendant to walk back and forth or even to stand up, he said.
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This commitment also implies a mindset Harmless simulation of smoke that, just like the pilots, the flight attendant is in a full-motion cabin trainer a necessity, regardless of regulations. “If cabin adds realism to evacuations safety is going to be an integral part of flight managed by one flight operations, the interactions between the flight attendant; photos show an attendant and pilots need to be just as well August 2007 course conducted scripted as between the flight crewmembers,” by FACTS Training International. Schwartz said. An aviation department manager typically must be able to explain to senior corporate executives why the company should use flight attendants and how the new function will be managed. This means being ready with answers to many questions. “If you use flight attendants, © Chris Sorensen Photography how do you recruit them?” he said. “What char- acteristics and qualifications are required? Do in the past, says Colette Hilliary, program man- you network or outsource? Full-time or part- ager for cabin safety and flight attendant train- time people? Do you have different qualifica- ing, FlightSafety International. A strong focus tions for full-time and part-time people? In any on crew resource management, understanding case, if you use a flight attendant, how does the dynamic variables and informed decision mak- flight attendant fit into the crew? Is he/she just ing under the stress of an emergency situation an additional person in the back of the airplane or outside the normal scope of responsibility or an integral part of the crew? Procedurally, constitute the new model. how do the pilots and flight attendant commu- Examples include sufficient understanding nicate and interrelate? What kind of briefing do of fire extinguishers to knowledgeably override Today’s drills on [the pilots] conduct for the flight attendant?” simple rules for extinguishing different classes fighting cabin fires in Judith Reif, president and contract flight of fire; familiarization with the general opera- business jets cover attendant for JR Flight Services and a member tion of aircraft radios; how to use a quick- informed decision making of the NBAA Flight Attendants Committee, donning oxygen mask; jump seat adjustment for unfamiliar scenarios. argues that business aviation operators’ crewing and harness release for © Chris Sorensen Photography decisions should be based on safety issues, not ar- extrication of an incapaci- bitrary factors. “Flying domestically, some opera- tated pilot from the cock- tors feel that a flight attendant is not needed and pit; and vigilance looking that the pilots can attend to the passenger needs,” for hazards outside the Reif said. “Anything could go wrong at any mo- airplane during ground ment, however. We are an asset to the pilots, and operations, especially we can be their eyes and ears in the cabin.” while taxiing and while in Except for breaks on long flights, pilots need the hangar. to be in the cockpit. “Once a pilot steps out of Some operators train the cockpit, the flight is a single-pilot operation, corporate flight attendants which becomes a safety issue,” Reif said. to shut down the aircraft engines and/or auxiliary Empowering Decision Makers power unit in an emer- Because few regulatory requirements govern the gency. Medically approved training of most flight attendants in business mixed-gas training equip- aviation, some training organizations aim to em- ment — an alternative to power them with more aviation education than the hyperbaric chamber — www.flightsafety.org | AeroSafetyWorld | October 2007 | 41 CABinsafety
also has been installed inside the cabin business jets have a third crewmember on configuration of more than 19 passen- trainer to provide corporate flight at- every flight,” Mykol said. “Our position is gers have a flight attendant in commuter tendants an optional training enhance- that any time operators have a stand-up and on-demand operations. There is no equivalent for corporate or private ment to experience their individual cabin — whether six or 14 passengers — aircraft that operate under Part 91. symptoms of hypoxia. This training has they really should have a trained third Relatively few operators are believed to been highly effective, Hilliary said. crewmember.” have a flight attendant aboard smaller jets Increasingly, corporate flight atten- In her experience, most passengers and turboprop airplanes.
dant trainees already have earned a U.S. flying on corporate/charter aircraft 2. NTSB. Runway Overrun and Collision, Federal Aviation Administration (FAA) have shown respect for the duties and Platinum Jet Management, LLC, Bombardier certificate of demonstrated proficiency responsibilities of the flight attendant, Challenger CL-600-1A11, N370V, Teterboro, through airline training or U.S. Federal said Mary Lou Gallagher, owner of New Jersey, February 2, 2005. Accident Aviation Regulations (FARs) Part 135, Beyond & Above Corporate Flight At- Report NTSB/AAR-06/04, Oct. 31, 2006. commuter and on-demand, operator tendant Training. Since the Challenger 3. Safety recommendation A-06-69 says, training.6 About half of the trainees in overrun at Teterboro, a greater number “Require that any cabin personnel on FlightSafety International corporate flight of cabin aides have completed the com- board … Part 135 flights who could be attendant courses have the certificate, pany’s corporate flight attendant course perceived by passengers as equivalent to a qualified flight attendant receive basic and many of them work concurrently for — typically at their own expense as [FAA-]approved safety training in at least airlines and business aircraft operators. freelance contractors. The comprehen- the following areas: preflight safety briefing Because of increased FAA surveil- siveness and demands of this training and safety checks; emergency exit opera- lance of the operational control of char- often were not appreciated beforehand tion; and emergency equipment usage. ter flights, such as under FAA Notice by the cabin aides or their employers. This training should be documented and 8000.355, Inspector Guidance for Part “By the end, we will have put them recorded by the Part 135 certificate holder.” In January 2007, the FAA said, “The FAA 142 Training Centers, operator respon- through a ditching in which they had is reviewing all current regulations and sibility for ensuring training — includ- to put on a life vest, jump in the water, the recommendations of the Part 125/135 ing Part 135 flight attendant training inflate the life raft and get into the raft,” Aviation Rulemaking Committee (ARC) — has come to the forefront in 2007 Gallagher said. “They are excited then to identify possible method(s) of requir- and operators are expected to be more because they feel very confident about ing that cabin personnel provided by the diligent in identifying all personnel using all the equipment on board.” certificate holder, who could be perceived by passengers as equivalent to a qualified who need training before flying charter Demand for wider voluntary use of flight attendant, are appropriately trained trips, Hilliary said. flight attendants could depend some- in the identified safety areas.” Initial plans The current standard in business what on passenger awareness, however. to address the issue with a Safety Alert for jet flight operations is flight attendant “Because there has been an explosion Operators and a notice to FAA personnel training specifically designed for corpo- of people buying their own aircraft, and were revised, and in September 2007, the rate/charter flights, says Doug Mykol, other people managing these aircraft, NTSB recommended that such guidance await revisions to Part 135, called the FAA’s president and CEO of AirCare Solu- I do not think the people sitting in the efforts “responsive” and classified these tions Group, which includes FACTS back are as educated as they should be steps as an “open acceptable” response. Training. The solution has become about who actually is in the cabin and 4. FSF Editorial Staff. “Assigning Seats advanced full-motion simulators for their credentials,” she said. They are still to Flight Attendants Requires Care in ● flight attendants with representative assuming they know, Gallagher said. Business Aircraft.” Cabin Crew Safety galleys, actual exit-opening mecha- For an enhanced version of this article, see Volume 38 (May–June 2003). nisms, standard emergency equipment,
42 | flight safety foundation | AeroSafetyWorld | October 2007 FoundationFocus
MembershipUPDATE
light Safety Foundation wel- MGM Mirage Eric Goodman comes the following new mem- MP Air Todd Hubbard Office Depot Aviation Eric Hube bers in 2007. Because of their Piarco International Airport Yea Fuh Hwang support and participation, the Pilatus Aircraft Poch F. Iliscupides FFoundation is able to make aviation Polish Air Navigation Services Agency (PANSA) Christopher Kelsey safer for all. Pratt & Whitney Canada Shabnam Kinkhabwala PT (Persero) Angkasa Pura II John Kolmos If you would like information Royal Oman Police Lee Chi Lien on the benefits of membership or Samsung Techwin Robin Low would like to join, please contact Sichuan Airlines Olga Marin Ann Hill, director, membership and Slok International Airlines David McBrien Southwest Airlines Pilots’ Association development, [email protected] or Michael McClintock Starr Aviation David Minty +1 703.739.6700, ext. 105. Superstructure Group Kjell Mjos Organizations Swets Information Services Carlos Moyano Swiss Federal Office of Civil Aviation ACSS Kamal C. Mututantri The Hershey Co. Aéroports de Montréal Mynor Pelaez U.S. National Center for Atmospheric Research Aeropuertos Españoles, Aena Tashi Phuntsho Vecellio Group AIM Aviation David Platten Air Accidents Investigation Branch, U.K. Individuals Erik Rigler Air Deccan Mark Riley Olumide Aiyegbusi Biblioteket Gerald Roberts Patricia W. Andrews Douglas Runyon Bristow Group Sid Baker Manuel Salhi Cloud Nine Aviation David J. Barger Werner Schweizer COMPOSAIR-ASD John Barrass Beverly A. Shihara Crown Point International Airport Kenneth Beaupre Minseok Song Cyprus Civil Aviation Department Fredric R. Boswell Raul Sosa Detroit Metropolitan Wayne County Airport Gregory Brown DNV Richard Bucknell Jason Starke Drummond Co. Maria J. Cara Amb. Edward W. Stimpson Dubai Aerospace Enterprises Michael Chamberlain Gary Tarizzo Dubrovnik Airport Ghim Leng Cheah Michael Trask Duke Energy Robert Courtenay NS Travers-Griffin Egyptian Aviation Academy (EAA) Horia Cristea John Trevett Enablon Panagiotis Droumpounetis Edward Turkovich Hifly Ulrich Eilers John Vincent International Safety Systems Montaser Fayek El-khaldy Don-Marshall Wanjoku Japan Aeronautical Engineers’ Association Thomas A. Farrier Ian Wigmore Jayrow (Safety Manager) Chen Seong Kit Felix Mark Winns Jordan Aviation Airlines Theresa Fisher Mark Wulber Kraft Foods Global Robert T. Francis Narinder Pal Yadav Mediterranean Aviation Co. Frank Frimor Wang Yi-Fen www.flightsafety.org | AeroSafetyWorld | October 2007 | 43 causalfactors
Into the Black Sea A go-around goes awry in Sochi, Russia.
@ Guy Daems/Airliners.net
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Sochi Black Sea Bulgaria Georgia Into the Black Sea Greece
Turkey Susan Reed
BY MARK LACAGNINA
patial disorientation, inadequate control Tu‑154 copilot for Armenian Airlines. He was inputs by the captain, lack of monitor‑ hired by Armavia in October 2004. ing by the copilot and the failure of both Both pilots were based in Yerevan and had pilots to respond to a terrain awareness a rest period of more than 24 hours before the andS warning system (TAWS) warning were accident flight. “It should be noted that it was among the factors that led to the crash of an difficult for the crew to take adequate rest dur‑ Airbus A320 during a missed approach to Sochi ing the day before the night flight due to impair‑ (Russia) Airport, according to the final report by ment of biorhythms,” the report said. “That is the Russian Air Accident Investigation Commis‑ most likely why, in their cockpit conversations, sion (AAIC). the crewmembers mentioned that they had not The accident occurred in nighttime instru‑ [had] enough sleep.” ment meteorological conditions on May 3, 2006. The flight crew’s preflight documents indi‑ The aircraft was destroyed, and all 105 passen‑ cated that weather conditions at Sochi included gers and eight crewmembers were killed. calm surface winds, visibility of 2,700 m (1.7 mi) The aircraft, operated as Flight RNV‑967 by and a broken ceiling at 1,200 m (3,937 ft); tem‑ Armavia Airlines, was en route to Sochi from perature and dew point both were 11 degrees Yerevan, Armenia. Sochi is a resort city on the C (52 degrees F). Forecast conditions included Black Sea, about 560 km (302 nm) northwest of visibility greater than 10 km (6 mi) in light rain Yerevan. Estimated flight time was one hour. showers and mist, and a broken ceiling at 450 m The captain, 40, had 5,458 flight hours, (1,476 ft), with visibility occasionally 800 m (0.5 including 1,436 flight hours in A320s. He began mi) and vertical visibility occasionally 60 m (197 his aviation career as a copilot in Antonov An‑2s ft) in fog. and Yakovlev Yak‑40s. He served as a Yak‑40 The aircraft departed from Yerevan at 0047 captain for Ararat Airline for about six years be‑ local time with 10,000 kg (22,046 lb) of fuel, fore being hired by Armavia as an A320 copilot which the report said was sufficient to fly to in May 2004. He transitioned to A320 captain in Sochi and then either divert to the alternate September 2005. airport in Rostov, Russia, or return to Yerevan. The copilot, 29, had 2,185 flight hours, The cruise portion of the flight was con‑ including 1,022 flight hours in A320s. After ducted initially at Flight Level (FL) 300 (ap‑ receiving primary training at a civilian flight proximately 30,000 ft) and later at FL 340. The school, he served as an ATR 42 and Tupolev aircraft remained above the clouds during
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cruise, and icing conditions were not encoun‑ (558 ft). “The weather is around the limit but tered during the flight. OK so far,” the controller noted. The crew requested and received clearance Unstable Weather from the Tbilisi controller to resume the flight The report said that a cold front was nearing to Sochi. The cockpit voice recorder (CVR) then Sochi, and weather conditions at the airport recorded discussion about the Runway 06 ILS ap‑ were unstable. proach procedure and missed approach procedure. At 0104, a Tbilisi (Georgia) Regional Centre “Analysis of internal communications … controller told the crew that Sochi Airport shows that the situation in the cockpit was getting was reporting 2,000 m (1.2 mi) visibility and a complicated,” the report said. “The crew (especially 170-m (558-ft) ceiling. “This weather was below the captain) appeared to be eager to land in Sochi the established minimums for the landing aero‑ and nowhere else. Further conversations show that drome,” the report said. the crew did not even wish to bother the Sochi The published minimum visibility and approach controller once more, so as not to get an ceiling for the instrument landing system (ILS) unfavorable weather forecast from him.” approach to Runway 06 at Sochi were 2,500 m The crew began the descent at 0152. The (1.6 mi) and 170 m; the published minimums report said that statements by the captain, who for the ILS approach to Runway 02 were 3,000 m was flying the aircraft with the autopilot and (1.9 mi) and 220 m (722 ft).1 autothrust systems engaged, indicated that he While under Tbilisi’s control, the crew was annoyed that the descent rate — about 1,000 established radio communication with a Sochi fpm — was not as high as he expected. “This approach controller and asked if the weather fact shows that either the captain did not fully conditions at the airport were expected to understand the autopilot work algorithm in improve. The controller said that the forecast for the ‘DESCENT’ mode or was in a state of high the next two hours was for a visibility of 1,500 m psycho-emotional strain with an imperative to (0.9 mi) and a ceiling at 150 m (492 ft). How‑ land at Sochi as soon as possible,” the report said. ever, the controller failed to note that these were While discussing autopilot operation during forecast as occasional conditions. the initial descent, the copilot voiced an exple‑ Based on this information, the crew told the tive and said, “Who operates such flights with Tbilisi controller that they wanted to return to the jitters and not enough sleep?” After the crew Yerevan. At the time, the aircraft was 180 km (97 changed the autopilot and autothrust modes, the nm) from Sochi. The Tbilisi controller cleared descent rate increased to 2,000 fpm. the crew to turn back toward Yerevan. At 0200, the Tbilisi controller told the crew to establish radio communication with Sochi ‘Around the Limit’ approach control. The crew reported that they About 10 minutes after turning back toward were descending to 3,600 m (11,812 ft). The Yerevan, the crew again contacted the Sochi Sochi controller told the crew that they were controller and asked for the current weather “flying too high” and to continue the descent to conditions. “While waiting for the results, the 1,800 m (5,906 ft). crew told the Sochi controller that they had “During descent and approach, the crew of deputies aboard,” the report said. “This informa‑ Flight RNV‑967 was kept informed of the ob‑ tion was not true. Analysis of the crew conver‑ served weather conditions,” the report said. At sations … shows that the crew intentionally about 0202, the controller advised that visibility misinformed the controller in order to obtain a was 4 km (2.5 mi) and the ceiling was overcast positive weather forecast.” at 800 m (2,625 ft). The Sochi controller said that visibility was The approach to Runway 06 is conducted 3,600 m (2.2 mi) and the ceiling was at 170 m over the sea. The aircraft was at 3,120 m (10,237
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ft) and about 45 km (24 nm) from the runway when the crew began the turn to final. The Airbus A320 aircraft overshot the turn, and the crew turned right to a heading of 090 degrees to intercept the extended centerline.
‘Negative Overreaction’ At 0207, the controller told the crew that the cloud base was at 160 m (525 ft) and visibility was 4,000 m (2.5 mi), and to descend no lower than 600 m (1,969 ft). “The information about the deteriorated weather conditions caused a negative overreac‑ tion, with the use of expletives,” the report said. “The crew [discussed] the issue for three minutes, swearing about the controller’s action even be‑ evelopment of the A320 began in 1984, and deliveries began in 1988. It is the first subsonic commercial airplane with major tween [conducting] the items of the checklist. Such primary structures manufactured from composite materials, a behavior by the crew inevitably must have resulted D “fly-by-wire” control system and sidestick manual controls. in an increase of their psycho-emotional strain.” The A320 accommodates two flight crewmembers and up to 180 During this time, the autopilot captured the passengers. The engines are either CFM International CFM56s or IAE localizer and the selected altitude, 600 m. The V2500s. Fuel capacities are 23,859 liters (6,304 gal), standard, and crew reduced airspeed and began extending the 29,659 liters (7,836 gal), maximum optional. Maximum standard takeoff weight is 73,500 kg (162,038 lb). flaps and slats. Maximum standard landing weight is 64,500 kg (142,197 lb). At 0209, the approach controller advised Maximum operating speed is Mach 0.82. Optimum cruising speed is that weather conditions were “4,000 by 190” and Mach 0.78. Service ceiling is 39,000 ft. Range in standard configuration told the crew to establish radio communication is 4,807 km (2,596 nm). with the tower controller. The aircraft was about Source: Jane’s All the World’s Aircraft 10 km (5 nm) from the airport when the crew reported that the landing gear was extended and told the tower controller that they were ready to after the controller cleared the crew to land, he land. was told by a weather observer that the ceiling The tower controller said that visibility was was at 100 m (328 ft). 4,000 m (2.5 mi) in light rain showers and the The A320 was 7 nm (13 km) from the ceiling was at 190 m (623 ft), and cleared the runway and descending through 390 m (1,280 crew to land. ft) when the controller said, “Flight RNV‑967, During this time, the autopilot captured the abort descent, clouds at 100 meters, right-hand glideslope, and the aircraft began to descend climbing turn to 600 meters.” at about 800 fpm; indicated airspeed was 140 Among the initial go-around actions kt. The aircraft was descending through 465 prescribed by the A320 flight crew operating m (1,526 ft) at 0211, when the crew selected manual are to move the thrust levers to the full flaps. “The aircraft was stabilized on the “TOGA” — takeoff/go-around — position, re‑ glideslope, in the landing configuration and was tract the flaps and slats to the go-around setting, completely ready for landing,” the report said. and retract the landing gear after a positive rate of climb is achieved. ‘Abort Descent’ “Not a single action of those required in The report said that the ceiling dropped the go-around procedure … was performed by abruptly as the aircraft neared the runway. Soon the crew, [indicating] that they were unable to www.flightsafety.org | AeroSafetyWorld | October 2007 | 47 causalfactors
evaluate the current situation adequately,” the warning, and disengaged the autopilot because report said. they doubted that it was functioning properly. Instead, the crew used the push-to-level- Using his sidestick, the captain reduced the off button on the flight control unit to stop pitch angle from 21 degrees to 4 degrees and the descent and selected a heading of 172 de‑ the bank angle from 25 degrees to about 20 grees. “As a result, the aircraft entered a turn degrees. Indicated airspeed increased from 129 to the right with a roll angle up to 25 degrees, kt to 140 kt, and the rate of climb decreased to maintaining an altitude of 1,114 ft (340 m),” about 400 fpm. the report said. Figure 1 shows the aircraft’s The rudder pedals in an A320 do not have flight path. to be used to make a coordinated turn, but The crew then set 3,200 ft in the altitude recorded flight data showed that forces up to selector and engaged the autopilot’s open-climb 15 kg (33 lb) were applied to the right pedal. mode. As a result, the aircraft pitched nose-up “The pedal inputs … might have been caused and began to climb at about 2,400 fpm. by transfer [of the captain’s] knowledge of fly‑ The aircraft was in a climbing turn, in landing ing another previous aircraft type, while under configuration, at 1,150 ft when an aural low- stress,” the report said. energy warning was generated at 0212:04. The re‑ At 0212:20, the altitude-selector setting was port said that the crew responded by moving the changed to 1,969 ft (600 m), and the captain thrust levers to the TOGA position. This resulted began to move his sidestick forward. The report in deactivation of the autothrust system and en‑ said that the captain might have overreacted to gagement of the autopilot go-around modes. the downward movement of the flight direc‑ A few seconds later, however, the autopi‑ tor pitch-command bars in his primary flight lot was disengaged. The report said that the display (PFD) when the selected altitude was re‑ crew likely had been surprised by the aircraft’s duced. The sensation of acceleration and the ab‑ maneuvering behavior and the low-energy sence of external visual cues might have caused the somatogravic illu‑ sion that the aircraft Armavia A320 Flight Path was pitching nose-up. Another possibility was that the captain Black Sea moved the sidestick
Sochi forward in reaction to Airport an indication on the PFD that airspeed was Ini tial M iss ed nearing the limit for A p p o the aircraft’s configu‑ r a c
h
ration — landing gear ILS Runway 06 P
r
o
c
e
✖ d extended and flaps/
u Accident r Site e slats in the landing configuration.
240° “The actual reason for such actions by the Flight Path captain could not be
determined,” the re‑ ILS = instrument landing system port said. “However, it Source: Susan Reed can be stated that such Figure 1 inadequate piloting
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was caused by a lack of monitoring of flight pa‑ about 5 degrees nose-down when the A320 rameters — in particular, pitch and roll angles.” struck the sea at 0213, at an indicated airspeed of 285 kt. (The accident occurred less than 80 Crossed Controls seconds after the crew received the “abort de‑ The aircraft was descending through 1,626 ft scent” instruction.) in a steep right turn when the captain told the The aircraft sank in 1,540 ft of water. “Only copilot to retract the flaps and slats. Indicated a small portion of the wreckage, less than 5 per‑ airspeed was 186 kt and increasing. cent, was found and recovered from the water At 0212:45, the captain made sidestick surface,” the report said. Examination of the inputs that increased the aircraft’s nose-down 52 bodies and numerous body parts that were pitch attitude and right bank angle. Two seconds recovered led to the conclusion that the cause later, a TAWS “pull up” warning was generated, of death of the occupants was “severe trauma and the copilot said, “Level off.” The aircraft was incompatible with life,” the report said. descending at about 4,300 fpm, and bank angle Based on the findings of the investigation, had increased to 39 degrees. the AAIC made several recommendations. “At this moment, the copilot intervened and Among them were that the aviation administra‑ moved [his] sidestick to the left stop position tions in the Commonwealth of Independent to counter the increasing right bank, while the States should “draw the attention of A320 captain continued making control inputs to crews to the necessity of immediate response to increase the right bank,” the report said. “Appar‑ activation of [a TAWS] warning (even if other ently, the copilot was trying to counter the bank, warnings are on at the same time) in the case of only. However, while moving the sidestick side‑ instrument flight or flight in difficult weather ways to the stop position, he had made forward conditions or in the mountains, [and] introduce control inputs on it as well.” relevant exercises in simulator training pro‑ The copilot had not called out his control in‑ grams to practice these actions.” tervention or engaged the take-over pushbutton The report included comments and recom‑ on his sidestick, which would have deactivated mendations by the French Bureau d’Enquêtes et the captain’s sidestick. The captain apparently d’Analyses pour la Sécurité de l’Aviation Civile was not aware of the copilot’s sidestick inputs. (BEA). One comment noted that the tower As a result, the A320’s autoflight system “added controller was authorized by Russian aviation and averaged” the captain’s and copilot’s un‑ regulations to refuse the landing. “This flight coordinated control inputs, the report said. A was, however, an international flight governed by “DUAL CONTROL” warning usually is gener‑ different regulations, which specifically allow the ated in this situation; however, because of the captain to descend to [the ILS decision height] higher-priority TAWS warning that was being before deciding on a go-around,” the BEA said. generated, the dual-control-input warning was “Thus, it would be desirable for the Russian Civil not generated, the report said. Aviation Authority to clarify its doctrine on inter‑ “The captain twice moved the sidestick half‑ ventions by ATC in relation to the responsibilities way backward, possibly reacting to the [TAWS that normally fall on the captain.” ● warning],” the report said. “But, at the same time, This article is based on the English translation by the BEA the copilot was inadvertently making nose-down of the AAIC’s “Final Report on the Investigation Into the inputs, which might have led the captain to Accident Involving the Armavia A320 Near Sochi Airport believe that the aircraft’s response to the control on 3 May 2006.” The 57-page report contains appendixes. inputs in the pitch channel was not adequate.” In the final seconds of the flight, both pilots Note made nose-up control inputs. The bank angle 1. Russia measures altitude in meters. The A320 can was about 10 degrees, and pitch attitude was display altitude in meters as well as in feet. www.flightsafety.org | AeroSafetyWorld | October 2007 | 49 DataLink
Separation Maintained No loss-of-separation incidents in U.K. commercial aviation in 2006 involved risk of collision.
By Rick Darby
he 2006 rate of “risk-bearing” aircraft that no Category A airproxes occurred. Six proximity incidents — airproxes — in events fell into Risk Category B, “safety not as- U.K. commercial air transport, in which sured,” in which “the safety of the aircraft was aircraft separation was compromised, compromised.” That number was the lowest wasT the lowest in a decade.1 The most common in the period beginning in 1997. Categories A causal factor in those airproxes was attributed and B combined are known as “risk-bearing” to air traffic controllers, according to a newly airproxes.3 released report by the U.K. Airprox Board The UKAB found no “common thread” (UKAB).2 among the six Category B events. One oc- In 2006, there were no Risk Category A, curred over Scotland, the others over vari- “risk of collision” airproxes, in this industry ous parts of England. “In airspace terms, sector (Table 1). It was the first time since 2003 two of the six airprox [incidents] occurred
No “Risk of Collision” Airproxes in 2006 U.K. Commercial Air Transport Airproxes by Risk Category, 1997–2006
Risk Category 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Category A 9 1 4 6 0 1 0 1 1 0 Category B 20 14 12 8 14 7 12 7 7 6 Category C 67 82 83 85 65 70 54 67 78 68 Category D 0 1 0 1 4 4 0 4 1 0 Total 96 98 99 100 83 82 66 79 87 74
Category A = risk of collision; Category B = safety not assured; Category C = no risk of collision; Category D = risk not determined
Source: U.K. Airprox Board
Table 1
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in terminal control areas and one each on an Hull Loss Fatalities Down airway; an ADR [advisory route]; [and] in Class D and Class G airspace,” the report said.4 Accidents by Injury and Damage, Worldwide Commercial Jet Fleet “The conclusion is that such wide variability 10 does not point to a common theme with the need for concerted action in a particular area 9 of operations.” 8
Figure 1 and Table 2 show the airprox rates 7 for 1997 through 2006. The 2006 rate of 0.37 6 risk-bearing airproxes per 100,000 flight hours is a decrease from 0.52 in the previous year, 5 an improvement of 29 percent. The rate had 4 been as high as 2.46 per 100,000 flight hours in 3 CAT Rate (A+B+C+D) 1997. Of the 74 total airproxes involving at least 2 one commercial air transport aircraft in 2006, hours per 100,000 ight rates airprox CAT 1 CAT Rate (A+B) the most common causal factor — “did not 0 separate/poor judgment” — was attributed to 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 controllers. Table 3 (p. 52) lists causal factors Year assigned four or more times.5 CAT = commercial air transport; Category A = risk of collision; Category B = safety not The second most frequent causal factor, assured; Category C = no risk of collision; Category D = risk not determined “sighting report,” was considered irrelevant. Note: Figure includes logarithmic trend lines. CAT rate A+B represents risk-bearing airproxes. The report said, “An informal definition of this Source: U.K. Airprox Board causal factor might be ‘without the slightest Figure 1 doubt a Risk Category C airprox.’” The third- and fifth-ranked causal factors were significant in terms of industry concerns report says that the reduction in civil-military about “infringements” of airspace and level aircraft encounters in 2006 is “of particular busts, respectively, the report said. note,” with the 46 in 2006 in contrast to an The UKAB investigates airproxes involving annual average of 72 in the prior years of the general aviation and military aviation aircraft, period, 1997–2005. The year 2006 ended with including helicopters, as well as commercial air a total of 159 airproxes, compared with the transport. Table 4 (p. 52) shows total airproxes previous five-year average of 198, a 20 percent by civil and military aircraft involvement. The reduction. ●
Airprox Rate Down U.K. Commercial Air Transport Airproxes per 100,000 Flight Hours, 1997–2006
Rate 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Risk category A + B 2.46 1.19 1.20 1.01 1.00 0.59 0.86 0.54 0.52 0.37 Risk category A + B + C + D 8.14 7.78 7.43 7.20 5.95 6.00 4.72 5.32 5.63 4.62 Flight hours (thousands) 1,179 1,259 1,332 1,389 1,395 1,366 1,398 1,485 1,546 1,602
Category A = risk of collision; Category B = safety not assured; Category C = no risk of collision; Category D = risk not determined Note: Flight hours are supplied by the U.K. Civil Aviation Authority and Eurocontrol.
Source: U.K. Airprox Board
Table 2 www.flightsafety.org | AeroSafetyWorld | October 2007 | 51 DataLink
Separation Loss Most Common Factor Most Common Airprox Causal Factors, U.K. Commercial Air Transport, 2006
Rank Causal Factor Total Attributed to 1 Did not separate/Poor judgment 19 Controller 2 Sighting report 9 Other 3 Penetration of CAS/SRZ/ATZ without clearance 8 Pilot 4 Not obeying orders/Not following advice from ATC 7 Pilot 5 Climbed/Descended through assigned level 7 Pilot 6 Inadequate avoiding action/Flew too close 6 Pilot 7 Did not adhere to prescribed procedures 4 Pilot 8 Did not pass or late passing of traffic information 4 Controller 9 Controller perceived conflict 4 Controller
CAS = controlled airspace; SRZ = special rules zone; ATZ = aerodrome traffic zone; ATC = air traffic control Note: An airprox could be assigned more than one causal factor.
Source: U.K. Airprox Board
Table 3
Fewer Civil-Military Airproxes in 2006 U.K. Airprox Totals by User Category, 1997–2006
User Category 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Civil-civil 115 129 113 100 97 109 87 109 99 95 Civil-military 78 53 81 78 73 77 67 69 74 46 Military-military 14 16 13 18 20 31 23 22 8 13 Other 1 3 1 2 5 4 4 7 7 5 Totals 208 201 208 198 195 221 181 207 188 159
Source: U.K. Airprox Board
Table 4
Notes The UKAB is an independent organization jointly sponsored by the CAA and the Ministry of 1. The U.K. Civil Aviation Authority (CAA) defines an Defence. airprox as “a situation in which, in the opinion of a pilot or a controller, the distance between aircraft 3. Other risk categories are C, “no risk of collision,” and as well as their relative positions and speed [were] D, “risk not determined.” Risk Category D comprises such that the safety of the aircraft involved [were] or incidents in which there is insufficient, or conflict- may have been compromised.” Airproxes in the data ing, evidence that precludes determining the degree occurred in U.K. airspace and included airplanes and of risk. helicopters. 4. An advisory route is defined as “a designated route 2. U.K. Airprox Board (UKAB). Analysis of Airprox in along which air traffic advisory service is avail- UK Airspace. Report no. 17, July 2006–December able.” Class D in the United Kingdom is controlled 2006. Available via the Internet at
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Handle With Care Appropriate equipment is the key to helping disabled passengers board and exit the aircraft.
REPORTS • A scissor-lift vehicle. “The wheelchair passenger is pushed into the vehicle at Manual Handling Risks During ground level, [and] the lift is then raised Assistance of Disabled Passengers mechanically to a height level with the Boarding or Disembarking Aircraft aircraft entrance and the passenger can be U.K. Health and Safety Executive Transportation Section. Sector wheeled into the aircraft,” the report says. Information Minute (SIM) 05/2007/07. August 2007. 15 pp. References, appendixes. Available via the Internet at
aircraft. If the device is mounted on the back of a regression is a statistical technique designed to vehicle and the lifting platform extends over the predict whether an event of interest will occur. top of the vehicle cab, the cab restricts the mini- Sector characteristics were derived for traffic mum height, and this can be a problem for small samples from high-altitude and low-altitude aircraft. … For larger aircraft, the maximum plat- sectors. In the high-altitude sector sample, vari- form height may not reach the aircraft entrance.” ables included the number of heading changes, The report says, “The successful use of lift- the number of transitioning aircraft and aver- ing aids will depend on the equipment available, age control duration. In the low-altitude sector the efficient maintenance of the equipment, and sample, variables were the number of point-outs the communication between aircraft/airline and [transferring the radar identification of an aircraft the ground handlers, to ensure the equipment is to another controller without transferring radio available at the gate.” communication because the aircraft will be in Specifications and standards for equipment the other’s airspace only briefly], the number of are listed, as is guidance for inspectors of airline handoffs and the number of heading changes. practices for conveying disabled passengers on “In the high-altitude [sector] sample, every and off aircraft. heading change that occurred increased the likelihood of an OE by 128 percent, every tran- Prediction and Classification of sitioning aircraft increased the likelihood of an Operational Errors and Routine Operations OE by 26 percent and every one-second increase Using Sector Characteristics Variables in average control duration increased OE likeli- Pfleiderer, Elaine M.; Manning, Carol A. U.S. Federal Aviation hood by 2 percent,” the report said. Administration (FAA) Office of Aerospace Medicine. DOT/FAA/AM- 07/18. Final report. July 2007. 16 pp. Tables, references. Available via In the low-altitude sector sample, “every the Internet at
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planning for NextGen, and the challenges that such as active air traffic controllers and technicians. the FAA and the JPDO face. Our work on past air traffic control modernization “During the last few years, FAA has made projects has shown that a lack of stakeholder or significant progress in implementing business- expert involvement early and throughout a proj- like operations and procedures for managing ect can lead to costly increases and delays.” and acquiring air traffic control systems which have improved FAA’s management of the current WEB SITES system and should better position the agency to manage the enormously complex transition to NASA Icing Branch, NextGen,” Dillingham said. “However, further
and anti-icing decisions [including] private pilots as well as those who fly business, corporate, air taxi, or freight operations in fixed-wing aircraft.” According to the course description, “A Pilot’s Guide to Ground Icing” covers:
• Risks and problems created by ground icing;
• Anticipating and detecting ground icing;
• Aircraft deicing/anti-icing fluids; and, • Advisory information circulars catego- • Deicing operations. rized by airport, flight crew, operations, air transport, air safety and airworthiness; The course introduction says experienced pilots can reinforce knowledge acquired during many • Handbooks and manuals, such as the years of commercial and airline flights, expand Handbook on Medical Assessment of Civil their knowledge base in specific areas or dispel Flight Crew; erroneous icing theories. • A list of regulatory materials and airwor- The course is self-paced, requiring one thiness directives that link electronically to three hours, depending on the number of to civil aviation authorities in Australia, course topics (modules) and related informa- Canada, France, the United Kingdom, the tion that users explore. The program design is United States and several other countries; user-friendly and allows customization to create a personal training syllabus. This multimedia • Annual India Air Transport Statistics course uses computer-based training tech- reports from 1997 through 2006 in English niques, such as interactive animation, videos and Hindi; and, and multiple pop-up screens. • Bilateral air service agreements for 2005, The online tutorial and help icon provide as- 2006 and 2007. sistance with navigation, special features, system requirements and operational issues. The annual statistical reports contain compara- tive statistics by airline, showing domestic and Directorate General of Civil Aviation (DGCA) India, international flights, fleet strength and aircraft
• India’s Civil Aviation Requirements; ** Government Accountability Office 441 G St. NW, Room LM • Annual accident summaries from 1990 Washington, DC 20548 U.S.A through 2005 in English and Hindi; — Rick Darby and Patricia Setze
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Hammered by Hail Flight crew faulted for inadequate use of radar information.
BY MARK LACAGNINA
The following information provides an aware- level,” the report said. “At the time and in the ness of problems in the hope that they can be region of the accident, violent storms accompa- avoided in the future. The information is based nied by hail were observed at several locations. on final reports by official investigative authori- According to eyewitnesses, the hailstones were ties on aircraft accidents and incidents. as big as ping-pong balls (40 mm [1.6 in]); some were even 50 mm [2 in] in diameter.” JETS The commander declared an emergency, reporting that the aircraft had encountered ‘Supercell Storms’ on Departure Route a “very heavy hailstorm,” and received clear- Boeing 737-300. Substantial damage. No injuries. ance from air traffic control (ATC) to return to he aircraft took off from Geneva Inter- Geneva. national Airport with 126 passengers for The windshield in front of the copilot was Ta scheduled flight to London the morn- cracked, and the commander told the copilot to ing of Aug. 15, 2003. The 737 was climbing don his oxygen mask and goggles, and to con- through about 8,500 ft on a standard instrument duct the “Window Damage” checklist. departure route when the flight crew requested The report said that the hail did not ad- clearance to fly west of course, on a heading versely affect engine operation. The aircraft was of 310 degrees, for about 15 nm (28 km) to landed about 14 minutes after the hail encoun- avoid thunderstorm cells, said the final report ter and taxied to a stand, where the passengers published in June 2007 by the Swiss Aircraft Ac- were disembarked normally. Hail damage was cident Investigation Bureau. found on the leading edges of the wings and tail, “A few minutes later, the aircraft passed engine nacelles, windshield and radome. through a shower of hail, which seriously dam- The report concluded that the accident was aged it,” the report said. The hail encounter caused “by the aircraft flying into a shower of lasted about five seconds and occurred as the hail embedded in a thunderstorm cell, follow- aircraft was climbing through 15,400 ft over ing inadequate utilization of the information Oyonnax, France, about 35 km (19 nm) west of provided by the on-board weather radar.” It Geneva. noted that the crew of an aircraft following five “The hail cell which caused the accident was minutes behind the 737 on departure avoided part of a broad thunderstorm zone displayed the thunderstorms by diverting farther to the with good resolution by the on-board weather west. radar,” the report said. The report also said that soon after the “[Ground radar] showed returns characteris- 737 returned to Geneva, the crew of a depart- tic of supercell storms with a maximum intensity ing Hawker Siddeley 125 was instructed to fly www.flightsafety.org | AEROSafetyWorld | October 2007 | 57 OnRecord
the same departure route. ATC did not tell the The crew of a departing aircraft reported Hawker crew about the hazardous weather that visibility at the approach end of Runway that the 737 had encountered. The captain of 03 was better, and the A330 crew was radar- The aircraft was the Hawker said that the aircraft encountered vectored by ATC for the ILS approach to that “heavy rain” during the departure. After the runway. “At the 320-ft minimum, the visibility past the point where Hawker arrived at its destination in England, the was less than the required 1,500 m [about 1 mi], radome and the leading edges of its wings and so the crew initiated another missed approach,” it had sufficient fuel tail were found to have been damaged. the report said. to divert. The crew declared an emergency and report- Committed to Land ed that they would conduct the ILS approach to Airbus A330. No damage. No injuries. Runway 21 and use the A330’s autoland system he airplane was en route from Singapore to land. The pilot-in-command (PIC) said that and was scheduled to land in Perth, Aus- at the decision height, visibility was about 400 m Ttralia, at 0020 local time on Sept. 16, 2006. (1/4 mi) and he could see some of the approach Visual meteorological conditions (VMC) had lights. About 100 ft above the runway, the PIC been forecast for Perth, with a 30 percent prob- saw the runway threshold lights. “The landing ability of fog forming after 0200. was reported to be normal, and the crew had “In accordance with the operator’s fuel sufficient visibility to navigate to the terminal,” policy, fuel was not specifically carried for a the report said. diversion from the destination to an alternate After the incident, the aircraft operator aerodrome,” said the Australian Transport Safety changed its flight-planning fuel policy to require Bureau (ATSB) report. The en route alternate designation of an alternate airport for all flights was Learmonth, which is 599 nm (1,109 km) to Perth when fog is forecast. from Perth. The report said that Learmonth had no significant weather. Parking Brake Not Set Correctly About 2308, the flight crew received an Boeing 767. Substantial damage. No injuries. amended trend-type forecast (TTF) for Perth, fter a flight from Calgary, Alberta, Canada, indicating that fog would begin to form at 0030. on Oct. 11, 2006, the aircraft was landed The aircraft was past the point where it had Aat London Heathrow Airport and taxied sufficient fuel to divert to Learmonth when the toward the assigned stand. However, the crew crew began the descent to Perth at 2350. “Once could not taxi the 767 onto the stand because the crew commenced the descent, they were a handling agent was not there to activate the committed to a landing at Perth,” the report visual docking guidance system and monitor the said. aircraft’s arrival, the U.K. Air Accidents Investi- About 10 minutes later, the TTF again gation Branch (AAIB) report said. was amended to indicate that fog would form “As the aircraft was blocking the taxiway, before the aircraft arrived at the airport. Fog a member of the airport’s airside staff was dis- actually began forming at about 0015, and patched to marshal the aircraft onto stand; this visibility decreased from 2,000 m (1 1/4 mi) he did without event,” the report said. “Once the to 300 m (less than 1/4 mi) within the next 15 aircraft was on the stand, the marshaller left the minutes. area without placing any chocks in front of its The crew began an instrument landing sys- wheels.” tem (ILS) approach to Runway 21 at 0010. “The The commander believed that he had set crew reported that at the 250-ft [altitude] mini- the aircraft’s parking brake correctly by pull- mum, the visibility was less than the required ing the parking-brake T-handle on the center 800 m [1/2 mi], and they initiated a missed console while depressing the toe brakes on top approach,” the report said. of the rudder pedals. The crew then shut down
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the engines. Because a handling agent still had the ground left-wing-first about 0.3 nm (0.6 km) not arrived, the passengers were told to remain from the runway threshold. seated. About 15 minutes later, the aircraft began to Struck by a Runaway Baggage Cart roll forward. “At first, the pilots thought the pier Bombardier CRJ900. Substantial damage. No injuries. [airbridge] was being moved into position, but hile taxiing to the runway at McCarran soon the commander realized that the aircraft International Airport in Las Vegas the was moving forward and gathering speed quite Wnight of April 30, 2006, the captain quickly,” the report said. “He applied the toe noticed a train of baggage carts moving rapidly brakes and noticed the parking-brake T-handle toward the airplane from the left. was retracted.” The captain swerved right of the taxiway Noticing that accumulator pressure was low, centerline in an effort to evade the carts, but the the copilot activated the hydraulic pumps. The first cart in the train struck the CRJ’s left wing, 767 was stopped after rolling about 12 ft (4 m). became wedged between the wing and the taxi- The cowling on the left engine was dented when way, and was dragged about 150 ft (46 m), the it struck the pier as the aircraft came to a stop. NTSB report said. “In an open and frank report, the command- After the accident, the airline issued an er admitted that the cause of the accident was employee memorandum that reiterated the his failure to set the parking brake correctly,” the importance of ensuring that the braking system is report said. engaged before leaving baggage carts unattended.
Steep Turn During Circling Approach TURBOPROPS Learjet 35A. Destroyed. Two fatalities. he airplane was on a positioning flight Wing Separates After Storm Encounter from Twin Falls, Idaho, U.S., to pick up Mitsubishi MU-2B-35. Destroyed. One fatality. Tpassengers at Truckee–Tahoe (Califor- efore departing from Tulsa, Oklahoma, U.S., for nia) Airport the afternoon of Dec. 28, 2005. a positioning flight to Panama City, Florida, on Reported weather conditions included 2 1/2 BSept. 1, 2006, the pilot — who had more than mi (4,000 m) visibility, variable between 1/2 30,000 flight hours, including about 10,000 flight mi and 5 mi (800 m and 8 km), a broken ceil- hours in MU‑2s — was told that there were ing at 1,500 ft and winds from 220 degrees at no adverse weather conditions along the route. 15 kt, gusting to 22 kt, according to the U.S. The airplane was over northern Florida, National Transportation Safety Board (NTSB) descending from Flight Level (FL) 190 (about report. 19,000 ft) two hours later, when a warning was The flight crew conducted the global po- issued for thunderstorm activity southwest of sitioning system (GPS) approach, which had the pilot’s route. Thunderstorm activity also a final approach course of 104 degrees, and had been detected along the pilot’s route, but no established the Learjet on a left downwind for warning had been issued, the NTSB report said. Runway 28. The minimum descent altitude for The pilot lost control of the MU‑2 in a the circling approach was 8,200 ft — 2,300 ft thunderstorm. “A witness located approximately above airport elevation — and the published one mile south of the accident site reported he minimum visibility was 3 mi (4,800 m). heard a ‘loud bang,’ looked up and observed The Learjet was about 400 ft above the the airplane in a nose-down spiral,” the report ground when it overshot the turn to final for said. “The witness reported there were parts Runway 28 and entered a steep left turn, which separating from the airplane during the descent. one witness described as banked nearly 90 de- The witness said it was raining and there was grees. The airplane then descended and struck lightning and thunder in the area.” www.flightsafety.org | AEROSafetyWorld | October 2007 | 59 OnRecord
Investigators found that the left wing had clouds and had 7 mi (11 km) visibility; however, separated after the front and rear spars failed temperature and dew point both were 13 degrees from “catastrophic static up-bending overstress.” C (55 degrees F), indicating the possibility of fog. As they taxied the The report noted that the airplane was The King Air, arriving on a private flight equipped with weather radar and that the pilot from Trenton, New Jersey, was observed to Twin Otter to a stand, had not requested any deviations or asked make two approaches to Grand Strand’s Runway ATC about the weather ahead. ATC radar had 23, which is 5,996 ft (1,828 m) long. “During the lower section detected intense to extreme precipitation in the first approach, the airplane was observed of the nose landing the area of the accident. “During the flight, the ‘fish-tailing’ while about 30 ft over the runway,” pilot was given no real-time information of the the report said. The pilot told the airport tower gear, including the weather ahead,” the report said. controller that he was going around. “The controller asked the pilot if he had wheel, separated. Corrosion Causes Nosewheel Separation problems with the sea fog,” the report said. The De Havilland DHC-6. Substantial damage. No injuries. pilot said no and explained that the left engine he flight crew felt a “slight thump” dur- was producing “a little too much [power] and ing the landing roll at Glasgow (Scotland) would not come back.” TAirport the evening of March 22, 2007. As Witnesses said that during the second ap- they taxied the Twin Otter to a stand, the lower proach, the airplane climbed, rolled left, descend- section of the nose landing gear, including the ed in an inverted nose-down attitude and struck wheel, separated. terrain left of the runway. “Examination of the The lower fuselage was damaged by the sepa- airplane, airplane systems, engines and propellers rated landing gear components. “The aircraft rap- found no abnormal pre-impact condition that idly came to a standstill, resting on the projecting would have interfered with the normal operation remains of the nose leg,” the AAIB report said. of the airplane,” the report said. None of the nine occupants was injured. NTSB said that the probable cause of the ac- Investigators found that the separation was cident was “the pilot’s failure to maintain control caused by corrosion of the locknut that secures during the landing approach for undetermined the wheel fork to the strut. The nose landing reasons.” gear assembly had accumulated 6,566 hours and 11,184 cycles since overhaul. The report noted Destabilized Approach Ends in Tail Strike that the Twin Otter was frequently operated on De Havilland DHC-8-300. Minor damage. No injuries. beach landing strips. he commander was the pilot flying the trip After the accident, the aircraft operator re- from Dublin, Ireland, to Cornwall, England, vised several maintenance procedures, including Tthe afternoon of Dec. 31, 2006. He con- a requirement for an annual inspection of the ducted a visual approach to Runway 12 at about strut and locknut assembly for corrosion. 123 kt, or about 15 kt above Vref, the calculated reference landing speed, to account for surface No Reason Found for Loss of Control winds from the southwest at 25 to 30 kt, gusting Beech Super King Air 200. Destroyed. Six fatalities. to 36 kt, the AAIB report said. he NTSB was unable to determine why the “The flight data showed that a stable ap- pilot, who had an airline transport pilot cer- proach was achieved initially but that this Ttificate and about 3,400 flight hours, failed to became unstable at a late stage, probably due to maintain control of the airplane during approach a combination of the gusty conditions and the to Grand Strand Airport in North Myrtle Beach, associated large control inputs,” the report said. South Carolina, U.S., the night of Feb. 3, 2006. “During the final stage of the approach, the air- A weather observation about an hour before speed decayed to 94 kt, significantly below both the accident indicated that the airport was clear of Vref and the target approach speed.”
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The commander believed that the Dash 8’s tank to the right wing tank through the aircraft’s pitch attitude was not excessive on touchdown, crossfeed valve. but he noticed a caution light indicating that the “There was no fuel quantity gauge fitted pitch attitude was more than 6 degrees. “Aircraft to the ferry tank, and neither the aircraft nor technical publications alerted crews to the possi- ferry tank was fitted with a fuel flow gauge,” the bility of a tail strike if the pitch attitude exceeded report said. “The ferry fuel system was designed 6 degrees during the landing,” the report said. to be turned on in the cruise phase of flight after During the landing roll, a “TOUCHED one hour of flight. Fuel transfer was to cease RUNWAY” warning light illuminated. Exami- when the left wing tank had reached no more nation of the aircraft showed that the frangible than 95 percent of its capacity.” Continued fuel fairing on the tail-strike sensor was broken and transfer could cause fuel to be vented overboard. that there was light abrasion damage to the bot- Because the aircraft was not recovered, tom of the rear fuselage. investigators were unable to determine what caused the cowling scorch mark reported by PISTON AIRPLANES the pilot. The cause of the fuel loss also was not conclusively determined. “However, from the Fuel Loss Leads to Ditching available information, it is likely that the left fuel Piper Seminole. Destroyed. No injuries. tank was being overfilled by the ferry fuel sys- he aircraft — one of two Seminoles that tem and was venting fuel overboard,” the report were being ferried from the United States to said. The overfilling might have been caused by TAustralia — departed from Santa Barbara, improper operation or malfunction of the ferry California, for the first leg to Hilo, Hawaii, on tank system, or a malfunction of the aircraft’s June 9, 2006. During the flight, the pilot noticed fuel crossfeed system. that more fuel than expected was being drawn The other Seminole, which was equipped from the ferry tank; he also saw a scorch mark with the same ferry tank system, was landed in on the left engine cowling. Hilo with enough fuel remaining for more than “Following discussion with the pilot of the three hours of flight. accompanying Seminole, the pilot decided to shut down the left engine,” the ATSB report said. Out of Supplemental Oxygen at FL 270 About 7.5 hours into the flight, the pilot told Beech 56TC Baron. Destroyed. One fatality. ATC that the aircraft would have to be ditched ight VMC prevailed for the personal flight because it was seven flight hours from Hilo and from Glendive, Montana, U.S., to St. Paul, had enough fuel for only five more hours of NMinnesota, on March 17, 2006. The NTSB flight. report said that the flight appeared to progress The Seminole was intercepted by U.S. Coast without incident until ATC observed the airplane Guard and Navy aircraft and escorted toward climb 400 ft above its assigned altitude, FL 240. a ship. The pilot restarted the left engine and “After being notified of the deviation, the ditched the aircraft in calm seas 980 km (529 nm) pilot responded that he was attempting to look northeast of Hilo. “The pilot and copilot exited at his contrails,” the report said. the aircraft uninjured and were rescued by the The pilot then requested and received clear- nearby ship,” the report said. “The aircraft sank ance to climb to FL 270. About 30 minutes later, [within four minutes] and was not recovered.” the pilot asked ATC, “Did you hear me call in A 568-liter (150-gal) ferry tank had been in- a few times?” This was the last radio transmis- stalled behind the pilots’ seats, with the electric sion from the pilot, and attempts by ATC to re- pump switch and on/off valve within reach of establish radio contact were unsuccessful. the pilot. The ferry tank fed fuel to the left wing The airplane had been airborne about two tank, and fuel was transferred from the left wing hours when it overflew the destination. ATC www.flightsafety.org | AEROSafetyWorld | October 2007 | 61 OnRecord
requested assistance from the North American Engine Fails on Maintenance Ferry Flight Aerospace Defense Command, which scrambled Piper Twin Comanche. Destroyed. Three fatalities. fighters to intercept the Baron. The fighter pilots he airplane had been parked outdoors and observed that the airplane’s exterior lights were flown about 15 hours in the past 10 years. illuminated, but they could not see the pilot. TThe owner obtained a special flight per- “Multiple attempts to gain the pilot’s attention mit to have the airplane ferried 152 nm (282 by firing flares and doing an afterburner flyby km) from Raymond, Mississippi, U.S., to New were unsuccessful,” the report said. Albany, Mississippi, where an annual inspection The Baron had been airborne about four would be performed before the airplane was hours when it began to descend. Witnesses sold to a new owner, the NTSB report said. said that they heard a sound similar to a bomb The pilot had a commercial certificate and exploding when the airplane struck a hill in about 4,000 flight hours, but “there was no evi- Winfield, West Virginia, about 2250 local dence found to verify any flight time for the last time. 24 years,” the report said. The supplemental oxygen system installed in Although the permit specified that only the unpressurized airplane and a portable oxy- minimum crew could be aboard for the ferry gen bottle found in the cockpit were depleted. flight, there were two passengers aboard when The report said that the probable cause of the the Twin Comanche was taxied for departure accident was the pilot’s failure to ensure that he from Raymond on Dec. 1, 2005. had an adequate supply of supplemental oxygen, Winds were from 340 degrees at 12 kt, gust- his inadequate in-flight planning and decision ing to 15 kt, when the airplane took off from making, and his incapacitation by hypoxia. Runway 30, which was 3,992 ft (1,217 m) long. The airplane was about 100 ft above ground Narrow Pass, Low Ceiling level (AGL) when the right engine lost power. De Havilland DHC-2. Destroyed. Two fatalities. The report said that the pilot did not retract the he Beaver was the first in a flight of two landing gear or maintain minimum single- float-equipped airplanes en route from engine control speed, Vmc. The Twin Coman- TGalena, Alaska, U.S., to Anchorage on Sept. che banked steeply right and struck the ground 15, 2006. The pilot of the second airplane told in a near-vertical attitude. investigators that they were between 4,000 and 5,000 ft when they entered Mystic Pass in Denali HELICOPTERS National Park and then descended because of worsening weather conditions. Survey Flight Ends With Wire Strike The pilot of the second airplane said that he Bell 206B-3. Destroyed. Three fatalities. radioed the Beaver pilot that he was not com- he JetRanger was engaged in a noxious fortable with the deteriorating visibility and was weeds survey flight in Parkes, Australia, on turning around. The Beaver pilot replied, “Turn TFeb. 2, 2006. A witness driving on a road around if you can. … I’m not able to.” said that the helicopter was about 200 ft AGL “The second pilot reported that the last time when it passed his automobile on the right. The he saw the accident airplane was just before it helicopter then turned around and flew over the entered a cloud bank, as the flight neared the road at 50–60 ft AGL. narrowest part of the pass,” the report said. “The driver described that, at that time, the A search was launched after the Beaver was helicopter was ‘under full control, nothing wrong reported overdue in Anchorage. The wreck- with it and flying level,’” the ATSB report said. age was found in the pass two days later. The The helicopter was being flown at about airplane had struck terrain at 3,700 ft — 300 ft 61 kt when its left landing gear skid struck a below the ridge of a steep slope. powerline that crossed the road. “The helicopter
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was observed by the driver … abruptly chang- The 206B pilot conducted a climb and landed ing attitude before rotating as it fell to the left of — the report did not say how — at the Astoria its original direction of travel and striking the airport. He notified emergency personnel that “There is presently ground adjacent to the road,” the report said. he had lost radio contact with the R44 pilot and no single source of The pilot and the two weeds-control officers believed that the helicopter had crashed. were killed, and the JetRanger was destroyed The report said that the R44 had descended information available by the impact and fuel-fed fire. “There was no into the water at about 0825 local time. At 0845, damage to the powerline or its associated facili- U.S. Coast Guard search-and-rescue personnel to pilots on the ties and structures,” the report said. “The power- found two life vests and other debris about 1 supply company described the [powerline] as mi (2 km) offshore; weather conditions at the location of known being very strong, having a breaking load of 25 accident site included 1 mi visibility and a 100-ft powerlines or tall kN [5,622 lb] and being under high tension.” overcast. The bodies of the three occupants were The powerline was not marked and was not recovered later that day. structures that might required to be marked because it was less than 90 m (295 ft) above terrain. “There is presently Ice Ingestion Likely Caused Flameout represent a hazard to no single source of information available to Eurocopter AS 350-B3. Substantial damage. No injuries. low-level operations.” pilots on the location of known powerlines or he pilot warmed the engine for about six tall structures that might represent a hazard to minutes before taking off to spread pow- low-level operations,” the report said. Tdered limestone on an ice-covered lake in The helicopter was not equipped with a Eringsboda, Sweden, the morning of March 1, wire-strike protection system. “Due to the large 2006. A relatively low power setting was used number of variables associated with wire-strike during the overwater departure, said the Swed- accidents, the effect that the fitment of such ish Accident Investigation Board (AIB) report. equipment may have had in this instance cannot The helicopter was climbing through about be determined,” the report said. 130 ft when the engine flamed out. “The pilot immediately initiated an autorotation, at the ‘Go Back Up … It’s Too Low’ same time beginning a steep right turn into Robinson R44. Destroyed. Three fatalities. the wind toward land,” the report said. “The he R44 and a Bell 206B were on position- helicopter came down onto the ice, about 20 ing flights Aug. 13, 2006, from Vancouver, meters [66 ft] from the shore, at low forward TWashington, U.S., to Long Beach, Califor- speed but at a high rate of descent. The pilot nia, where they were to engage in aerial pho- was unhurt and [exited] the helicopter without tography. A fuel stop was planned in Astoria, assistance.” Oregon; but when the helicopters arrived, the Examination of the engine revealed damage to airport was reporting a 400-ft overcast and 5 mi three compressor blades. Noting that the helicopter (8 km) visibility in mist, the NTSB report said. had been parked outside in falling snow before the The 206B pilot told the R44 pilot, “I’m going to flight, the report said that the engine likely flamed go through it. Stay right behind me.” The pilot later out when it ingested a buildup of ice. told investigators that he had planned to fly west- The AIB recommended that the Swedish bound, over water, and find a break in the overcast. Civil Aviation Authority “point out to operators A passenger aboard the 206B said that the of this category of helicopter the importance of R44 was behind and above the 206B when they ensuring that ice, packed snow and water can- entered the fog. The R44 pilot radioed, “How not be drawn into the engine, since even small fast are you descending?” The 206B pilot an- amounts can cause the engine to stop.” The swered, “Very slow.” About 30 seconds later, the board also recommended that an autoignition R44 pilot said, “Go back up. It’s much lower than system be required as standard equipment in AS we thought. Go back up right now.” 350-B3 helicopters. ● www.flightsafety.org | AEROSafetyWorld | October 2007 | 63 OnRecord
Preliminary Reports
Date Location Aircraft Type Aircraft Damage Injuries Aug. 1, 2007 Fort Lauderdale, Florida, U.S. Piper Aerostar 601P substantial 3 none The right engine failed on final approach, and the airplane struck a traffic light and crashed on a road during the forced landing. Aug. 2, 2007 Easton, Washington, U.S. Robinson R44 II destroyed 4 fatal The helicopter was departing in VMC for a charter flight when witnesses saw the tail section move left and right. The R44 then pitched down and descended into mountainous terrain. Aug. 3, 2007 Eket, Nigeria Bell 412EP destroyed 1 fatal The helicopter crashed while maneuvering at Qua Ibom Terminal Airfield. Aug. 5, 2007 Ruidoso, New Mexico, U.S. Beech King Air E90B destroyed 5 fatal The airplane was departing in nighttime VMC for an air ambulance flight when it struck terrain about 4 nm (7 km) southeast of the airport. Aug. 9, 2007 Moorea, French Polynesia de Havilland Canada DHC-6 destroyed 14 fatal, 6 NA Both engines failed soon after the Twin Otter departed Moorea for a scheduled flight to Papeete. The airplane crashed and sank in a lagoon. Six passengers were not found. Aug. 11, 2007 Melville Hall, Dominica Learjet 35A substantial 6 none The airplane was on a charter flight from Antigua in daytime VMC when it overran the runway, traveled down an embankment and came to a stop on a road. Aug. 12, 2007 Pusan, South Korea de Havilland Canada Q400 substantial 74 NA The airplane veered off the runway on landing and came to a stop in a drainage ditch. No fatalities were reported. Aug. 13, 2007 Moscow Tupolev Tu-134 substantial 25 NA A landing gear collapsed when the airplane, operated by the Russian air force on a nonscheduled passenger flight, overran the runway. Aug. 16, 2007 Ketchikan, Alaska, U.S. de Havilland Canada DHC-2 destroyed 5 fatal, 4 serious Strong, gusty winds were reported when the float-equipped Beaver struck terrain during takeoff from a bay about 20 nm (37 km) north of Ketchikan. The airplane was on a chartered sightseeing flight. Aug. 16, 2007 Gulf of Mexico Bell 407 substantial 1 minor, 1 none The engine failed during a charter flight between two offshore platforms. The pilot deployed the emergency floats and landed on the water. A large wave then broke the windshield and rolled the helicopter inverted. The occupants exited the helicopter and were rescued by the crew of a shrimp boat. Initial examination of the engine revealed an uncontained failure of the third-stage turbine wheel. Aug. 20, 2007 Okinawa, Japan Boeing 737-800 destroyed 165 NA A fuel leak was observed when the airplane was taxied to the gate after landing at Naha Airport. All the occupants evacuated on slides before a fire erupted and an explosion occurred. No fatalities were reported. Preliminary investigation indicated that a bolt had separated from a wing slat assembly and pierced a fuel tank. Aug. 22, 2007 Curitiba, Brazil Embraer EMB-110P1 destroyed 2 fatal The Bandeirante struck terrain at 0035 local time while departing for a domestic flight to Jundiaí. Aug. 22, 2007 Pasto, Colombia Antonov An-26B destroyed 53 NA The airplane was en route from Cali to Villagarzón when the flight crew reported engine problems and diverted to Pasto. The twin-turboprop airplane overran the runway and traveled down an embankment. No fatalities were reported. Aug. 22, 2007 Houston Mitsubishi MU-2 none 1 serious A lineman was removing a wheel chock when his head was struck by a rotating propeller. Aug. 26, 2007 Kongolo, Democratic Republic of Congo Antonov An-32 destroyed 14 fatal, 1 NA The flight crew was attempting to return to the airport, after encountering engine problems on takeoff, when the airplane struck trees and crashed short of the runway. Aug. 31, 2007 Port-au-Prince, Haiti Cessna 208 Caravan destroyed 1 minor, 5 none The airplane overturned during a forced landing soon after takeoff.
NA = not available This information, gathered from various government and media sources, is subject to change as the investigations of the accidents and incidents are completed.
64 | flight safety foundation | AEROSafetyWorld | October 2007 Let us give you the world. AeroSafety W ORLD
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