Flight crews can reduce the possibility and effects of a bird strike by increased awareness and by following recom­ mended procedures.

16 aero quarterly qtr_03 | 11 Strategies for Prevention of bird­Strike events

bird­strike events are relatively common, occur most often on the ground or at low altitude, and are usually benign. However, bird strikes can have significant economic and occasional safety consequences for flight operations. Pilots and operators should be knowledgeable about the hazard, and flight crews should use facts, data, and standard operating procedures to reduce the potential for and consequences of a bird strike.

By Roger Nicholson, Ph.D., associate technical Fellow, aviation System Safety, and William S. Reed, Safety Pilot, boeing Flight technical and Safety

bird strikes are a lesser hazard to aviation strikes, accidents and serious incidents can ChaRaCteRiStiCS of BiRD StRikeS than other well­known hazards such as occur. aviation wildlife hazards encompass loss of control in flight, controlled flight into birds on the ground and in flight, terrestrial according to bird Strike committee uSa, terrain, and runway excursions, but they animals (e.g., deer, coyotes, cattle, camels), an organization that was formed in 1991 to can and do present risk that needs to and even airborne animals such as fruit facilitate the exchange of information and be addressed. the first bird strike was bats; however, this article focuses on bird promote the collection and analysis of recorded by the Wright brothers in 1905, strikes in particular. opera tors and flight accurate wildlife strike data, bird and other and the aviation wildlife hazard has crews should be aware of the risk of bird wildlife strikes cause more than $650 million been a risk to aviation ever since. the strikes, prevention strategies, and actions in damage to u.S. civil and military aviation January 15, 2009, ditching of uS airways to take following a bird strike. annually. in addition, bird strikes put the flight 1549 on the Hudson river in this article discusses the characteristics lives of crew members and passen gers at Weehawken, new Jersey, was the dra matic of bird strikes, presents practical infor­ risk — more than 200 people have been result of dual engine thrust loss arising from mation for flight crews, highlights the killed worldwide as a result of wildlife strikes an airborne encounter with a flock of canada importance of reporting bird strikes, and since 1988. the bird Strike committee geese. although boeing airplanes meet and provides resources for additional bird­ takes a similar data­driven approach to exceed the government regula tions for bird strike information. the bird strike issue that organizations such

17 WWW.boeing.com/commercial/aeromagazine figure 1: example of bird-strike damage bird­strike damage can be quite severe and can shut down jet engines.

as the commercial aviation Safety team airplane damage and effect on flight from (hawks and kestrels). most bird strikes (caSt) takes to reduce commercial aviation bird strikes are closely correlated to kinetic occur on or near the ground, highlighting fatality risk. (See www.cast­safety.org.) energy, derived from the mass (determined the need for wildlife management on airport experts within the u.S. Federal aviation by bird species) and the square of the grounds and in the vicinity. (See http:// admin istration (Faa), the u.S. Department speed of the collision. (a 20 percent wildlife­mitigation.tc.faa.gov/wildlife/ of agriculture, and the u.S. navy and increase in speed raises the kinetic energy downloads/baSH90­09.pdf.) u.S. air Force expect the risk, frequency, by 44 percent.) the aviation bird­strike hazard is a and poten tial severity of wildlife­aircraft Single or multiple large birds, relatively global and industrywide issue affecting collisions to grow over the next decade, small numbers of medium­size birds, and all aviation stakeholders, including pilots, based on increasing air traffic, bird popula­ large flocks of relatively small birds are all mechanics, airlines, airport operators, air tions, and the trend to twin­engine aircraft. problematic and have resulted in accidents. traffic controllers, wildlife personnel, aviation (See http://wildlife­mitigation.tc.faa.gov/ in the united States, a list of birds most safety analysts, airplane and engine manu­ wildlife/downloads/baSH90­09.pdf.) hazardous to flight has been identified: facturers, flight training organizations, and While bird strikes usually inflict most large flocking waterfowl (canada goose); the traveling public. boeing participates in damage on the engines, all areas of an air­ gulls; pigeons and doves; blackbirds, national and international groups dedicated plane can be damaged (see figs. 1 and 2). starlings, and sparrows; and raptors to exploring and addressing the problem of

18 aero quarterly qtr_03 | 11 figure 2: Locations of bird-strike damage three­quarters of bird strikes involve the wing or engines, but they can damage almost any part of an airplane.

Fuselage Windshield 4% 13% engine 44%

nose 8%

Wing 31%

bird strikes, and boeing airplanes meet and bird strike or an actual event. these PReveNtive StRategieS exceed regulatory bird­strike requirements. miscon ceptions include: boeing has many design features, including airports are responsible for bird control and ■■ birds don’t fly at night. system separation, system redundancy, should provide adequate wildlife control ■■ birds don’t fly in poor visibility, such as and structural attributes, to protect against measures. if large birds or flocks of birds in clouds, fog, rain, or snow. bird strikes beyond the four­pound regula­ are reported or observed near the runway, ■■ birds can detect airplane landing lights tory general bird­strike Faa require ment the flight crew should consider: and weather radar and avoid the airplane. (eight pounds for empennage). ■■ airplane colors and jet engine spinner ■■ Delaying the takeoff or landing when fuel markings help to repel birds. permits. advise the tower and wait for CommoN miSCoNCePtioNS aBout ■■ birds seek to avoid airplanes because airport action before continuing. BiRD StRikeS of aerodynamic and engine noise. ■■ take off or land on another runway that ■■ birds dive to avoid an approaching is free of bird activity, if available. a number of widespread misconceptions airplane. about bird strikes may give pilots a false in fact, none of these statements is sense of security and prevent them from scientifically proven. reacting appropriately to the threat of a

19 WWW.boeing.com/commercial/aeromagazine Wildlife strike facts

■■ more than 219 people traveling by ■■ between 1990 and 2004, u.S. airlines ■■ more than 950 civil aircraft collisions airplane have been killed worldwide reported 31 incidents in which pilots had with deer and 320 collisions with as a result of bird strikes since 1988. to dump fuel to lighten load during a coyotes were reported in the united ■■ between 1990 and 2009, bird and other precautionary or emergency landing States between 1990 and 2009. wildlife strikes cost u.S. civil aviation after striking birds on takeoff or climb. ■■ about 90 percent of all bird strikes more than $650 million per year. an average of 11,600 gallons of jet fuel in the united States are by species ■■ about 5,000 bird strikes were reported was released in each of these dumps. federally protected under the migratory by the u.S. air Force in 2010. ■■ Waterfowl (31 percent), gulls bird treaty act. ■■ more than 9,000 bird and other wildlife (25 percent), raptors (18 percent), and ■■ between 1990 and 2009, 415 different strikes were reported for u.S. civil pigeons/doves (7 percent) represented species of birds and 35 species of aircraft in 2010. 81 percent of the reported bird strikes terrestrial mammals were involved in causing damage to u.S. civil aircraft strikes with civil aircraft in the united between 1990 and 2009. States that were reported to the Federal aviation administration.

Source: bird Strike committee uSa

to prevent or reduce the consequences aDDitioNaL ReSouRCeS ■ embry­riddle aeronautical university of a bird strike, the flight crew should: (http://wildlifecenter.pr.erau.edu). additional information is available online ■ national bird Strike committees or ■■ Discuss bird strikes during takeoff through a number of industry groups. aviation Wildlife Hazard groups. and approach briefings when operating information includes significant strike at airports with known or suspected events, key issues to reduce strikes, risk bird activity. the imPoRtaNCe of RePoRtiNg assessment, system information, papers ■■ be extremely vigilant if birds are BiRD StRikeS and newsletters, and discussion forums. reported on final approach. if birds are expected on final approach, plan ■■ bird Strike committee uSa Flight crews and maintenance and line additional land ing dis tance to account (www.birdstrike.org). personnel are encouraged to report all for the possibility of no thrust reverser ■■ international bird Strike committee bird strikes because data are essential to use if a bird strike occurs. (www.int­birdstrike.org). quantify and manage the hazard. reporting ■■ international civil aviation organization bird strikes enables aviation authorities (icao) (www.icao.int/icao/en/ro/nacc/ to monitor the risk to aviation and the acilac/index.html). effectiveness of wildlife hazard mitigation measures. bird­strike data, together with

20 aero quarterly qtr_03 | 11 Factors contributing to the increase in wildlife strikes

■■ the great lakes cormorant population ■■ the north american nonmigratory ■■ the north american population of increased from only about 200 nesting canada goose population increased greater snow geese increased from adults in 1970 to more than 260,000 about fourfold from 1 million birds about 50,000 birds in 1966 to more nesting adults in 2006. in 1990 to more than 3.9 million in 2009. than 1 million birds in 2009. ■■ in 1890, about 60 european starlings about 1,500 canada geese strikes with ■■ the nesting population of bald eagles in were released in new york city’s central civil aircraft were reported in the united the contiguous united States increased Park. Starlings are now the second­ States between 1990 and 2009. about from fewer than 400 pairs in 1970 (two most abundant bird in north america 42 percent of these strike events years before DDt and similar with a late­summer popu lation of more involved multiple birds. chlorinated­hydrocarbon insecticides than 150 million birds. Starlings are ■■ a 12­pound canada goose struck by a were banned) to more than 13,000 pairs considered “feathered bullets,” having a 150­mph airplane at liftoff generates the in 2010. between 1990 and 2009, 125 body density 27 percent higher than kinetic energy of a 1,000­pound weight bald eagle strikes with civil aircraft were herring gulls. dropped from a height of 10 feet. reported in the united States. the mean body mass of bald eagles is 9.1 pounds for males and 11.8 pounds for females.

Source: bird Strike committee uSa

knowledge of the operational environment, combined into a single composite data if bird remains are available, trained are utilized by boeing as a basis of many record. reporters should provide as much personnel should identify the species airplane design features beyond regulatory information as possible, including: involved, or the bird remains should be requirements. bird­strike data also help collected using the correct procedure (as ■■ airplane model and series designation researchers understand the nature of out lined at http://wildlife­mitigation.tc.faa (e.g., 777­300). strikes and develop a scientific approach .gov/wildlife/speciesid.aspx) and bird­strike ■■ airplane serial number or registration. to reduce the cost and safety conse­ collection kit and shipped to a qualified ■■ Phase of flight. quences of bird strikes. laboratory. it is crucial to determine the ■■ Speed and altitude of the airplane. aviation stakeholders should report all species of the bird or birds involved in a ■■ geographical location of the airplane. known or suspected bird strikes to their bird strike and the location of the strike, ■■ Date and time of day. national or recognized wildlife strike data so that wildlife management can take ■■ origin and destination airport. repository (e.g., the Faa national Wildlife appro pri ate actions. effective wildlife man­ ■■ number and species of bird observed Strike Database in the united States) and agement involves controlling attractants, and struck. share the strike information with the airport often species­specific, including food, ■■ impact locations of strikes and damage operator, the airline safety department, foraging, roosting, and nesting opportu­ on airplane. and the aircraft and engine manufacturers. nities. managing the environment may be ■■ effect on flight (e.g., rejected takeoff, each of these individual reports will be necessary, even to the extent of grass air turnback, diversion).

21 WWW.boeing.com/commercial/aeromagazine the bird strike should be reported by the flight crew in the pilot’s log or by the maintenance crew in the maintenance log. after a bird strike, the airplane should be inspected for possible damage to airplane structure and airplane systems.

type and height, insects, rodents, and in the united States and canada, bird­ aviation wildlife hazard activity, both invertebrates, along with water sources strike information can be reported online at internally and externally. and land use, such as agriculture. http://wildlife­mitigation.tc.faa.gov/wildlife/ in the event of a bird strike, maintenance strikenew.aspx or via Faa form 5200­7 SummaRy personnel should follow the appropriate bird/other Wildlife Strike report. maintenance procedures for bird strike bird strikes have always been a part of inspection in the airplane maintenance hoW aiRLiNeS CaN get iNvoLveD aviation. While they usually cause no more manual. maintenance personnel must be than minor damage, they can pose a threat cognizant of the possibility that the bird airlines and other stakeholders can help to air safety. by being aware of the ongoing remains can contain infectious material. address the ongoing problem of bird strikes possibility of bird strikes and by following the bird strike should be reported by by participating in local, regional, national, recommended procedures, flight crews the flight crew in the pilot’s log or by the or international aviation wildlife hazard can reduce the possibility and effects of maintenance crew in the maintenance log. activities, such as bird­strike committees or a bird strike. after a bird strike, the airplane should be equivalent groups. For more information, please contact inspected for possible damage to airplane airlines can also form their own internal roger nicholson at roger.nicholson@ structure and airplane systems. aviation wildlife hazard group and designate boeing.com. a single point of contact for coordinating all

22 aero quarterly qtr_03 | 11 Practical bird­strike information for flight crews

although it is not possible to avoid all bird ■■ When landing is assured, consider landing ■■ auditory: noise of strike or noise attributed strikes, flight crews can take steps to reduce through birds versus a missed approach to resulting damage: engine surging, the chance of a bird­strike event. if a bird to avoid birds. this reduces the energy of compressor stalls, aerodynamic noise strike does occur, the appropriate action can the collision, the potential for increased from damaged radome, loss of pressur­ improve the flight crew’s ability to maintain damage associated with engines at a high ization from pressure vessel penetration. control of the airplane and land safely. power level, and the potential for multiple ■ olfactory: Smoke, odor, or cooked bird this information from the boeing Flight engine ingestions at low airplane energy smell. crew training manual provides flight crews states and low altitude. and flight operations personnel with ■■ avoid or minimize maneuvering at low ■■ engine indications: reduction or fluc­ practical information about preventing altitude to avoid birds. tuation in primary power parameter and managing bird­strike events. (e.g., engine pressure ratio, fan speed, or equivalent), abnormal fuel flow, abnormal BiRD StRikeS DuRiNg takeoff RoLL engine vibration monitoring (e.g., error PReveNtioN StRategieS vector magnitude or equivalent), engine if a bird strike occurs during takeoff, the failure, engine exceedances. ■ Pilots should not rely on onboard decision to continue or reject the takeoff is weather radar, landing lights, airplane made using the criteria found in the ■ Flight instruments: loss of data or markings, time of day, or visibility to rejected takeoff maneuver of the qrH. if a erroneous indications arising from prevent bird strikes. bird strike occurs above 80 knots and prior damage to air data sensors or angle­of­ ■ Flight operations may need to be to V1, and there is no immediate evidence attack sensors. modified in the presence of known or of engine failure (e.g., failure, fire, power ■■ other airplane systems or structure anticipated bird activity. loss, or surge/stall), the preferred option is affected directly by a strike: Damaged ■ Delay takeoff or landing in the presence to continue with the takeoff followed by an communications or navigation antennas, of bird activity. immediate return, if required. damage to exposed electrical wiring or ■ below 10,000 feet, keep speed below hydraulic lines, damaged radome or 250 knots if operationally possible. DeteCtiNg a BiRD StRike WhiLe weather radar, broken landing lights, ■ below 2,000 feet, climb at the maximum iN fLight or cascading and multiple effects from rate to reduce the flight time exposure sensor damage or engine damage. to a strike hazard. ■ Visual: birds seen in close proximity to ■ Descend with idle power and avoid the airplane or colliding with the airplane, extended low­altitude level flight, bird remains on windshield, cracked ReSPoNSeS to a kNoWN oR particularly over water courses, nature windshield. SuSPeCteD BiRD StRike reserves, or other areas of known or ■■ tactile: Vibration of airframe or engine, expected bird activity. immediate action thrust loss, asymmetric thrust, increased ■ Fly the airplane and maintain flight path drag, abnormal airplane handling control. characteristics. ■ monitor flight and engine instruments. 23 WWW.boeing.com/commercial/aeromagazine multiple engine failure or thrust loss Known or suspected airframe damage or ■■ be aware of the potential for loss or ■■ attempt to restart engine(s). engine damage erroneous air data and degraded flight ■■ maintain or reduce speed — do not control modes, including loss of envelope Severe engine damage accelerate unless necessary for safety of protection or limiting, unreliable airspeed, ■ Shut down engine according to flight or to maintain flight path control. propulsion systems in alternate mode. procedure. Damaged windshield or depressurization bird strikes during approach or landing Strong engine vibration ■ below 10,000 feet, discontinue climb ■ if the landing is assured, continuing ■■ reduce thrust, which will often reduce and level off. the approach to landing is the preferred vibration. ■ above 10,000 feet, descend to 10,000 option. if more birds are encountered, ■■ Shut down engine per flight crew feet or the minimum safe altitude. fly through the bird flock and land. operations manuals guidance. ■ maintain as low a thrust setting as Known or suspected strike with landing multiple engine ingestion and abnormal possible. gear extended or in takeoff or landing engine indications ■ if engine ingestion is suspected, limit configuration with high lift deployed ■ air turnback or diversion to nearest reverse thrust on landing to the amount ■■ use available system information to suitable airport. needed to stop on the runway. reverse assess possible damage to flight con­ thrust may increase engine damage, Known or suspected multiple engine trols and high lift devices, and make especially when engine vibration or high ingestion, with normal engine indications minimal and prudent changes in airplane exhaust gas temperature is indicated. ■■ consider air turnback or diversion to con figuration in accordance with the nearest suitable airport. flight phase. Postflight actions following a known or ■■ reevaluate decision to continue with ■■ use available system information to suspected bird strike extended­range twin­engine operational assess possible damage to landing ■■ report all known or suspected bird performance standards, extended range gear and associated systems, including strikes or bird activity on or in the vicinity operations, or overwater flight because exposed electrical, pneumatic, and of the airport via established procedures. engine damage or performance degra­ hydraulic systems, and potential effects ideally this information reaches all dation may manifest later in the flight. on the ability to steer and stop on stakeholders, including air traffic control, the runway. the airport operator, the airline, airplane Known or suspected strikes with large and engine manufacturers (particularly flocking birds, such as canada geese Known or suspected strikes to air data and the local representative), the national ■■ consider air turnback or diversion angle­of­attack sensors regulatory authority, and the appropriate to nearest suitable airport, because ■■ be aware that this may affect other national bird­strike committee or aviation damage may affect aerodynamic lift airplane systems and have cascading wildlife hazard group. and drag, subsequent fuel burn, and effects. ability to complete the flight safely.

24 aero quarterly qtr_03 | 11