Timing Is Everything

AIRPORTOPS hen the U.S. Federal Aviation that airport surface detection equipment, If the deployment repeats the success Administration (FAA) awards model X (ASDE-X) — a surface surveil- of systems already tested at Dallas-Fort a contract in late 2008 to lance system designed to identify and Worth (DFW) and San Diego inter- install runway status lights display traffic and, in enhanced versions, national airports, one result will be a W(RWSL) at 22 major U.S. airports1 in automatically alert air traffic control compelling case for updating interna- 2009–2011, the worldwide aviation com- (ATC) to imminent ground collisions — tional standards to add RWSL to existing munity will be anxious to hear about the has proved to be a key enabler. defenses against the human errors and new system’s effectiveness in preventing “We have an approval and a com- other causes of runway incursions. runway incursions. From 2001 to Febru- mitment of capital to go out and invest Saves So Far ary 2008, the FAA spent US$25.8 million hundreds of millions of dollars in get- The FAA cites two occurrences in 2008, to complete its research, development ting RWSL to these airports,” said Jaime both at DFW, as prime examples of and operational evaluation of RWSL. Figueroa, field demonstration manager, RWSL providing safety-critical situation- Available technology did not enable surface technology assessment, FAA al awareness quickly enough to prevent a a nation wide deployment in the mid- Air Traffic Organization (ATO) Opera- runway collision with complete inde- 1990s — the last time the FAA studied tions Planning. “That’s very significant pendence from air traffic control: RWSL. Today, about two-thirds of the because the decision says we have high-hazard runway conflicts can be already persuaded ourselves — both • A controller cleared the crew of a addressed “without adversely impacting technically and from a business-case Saab 340 for takeoff on Runway runway capacity or controller workload,” standpoint — that this is a solution we 36R from the intersection at Taxi- the FAA said. The difference today is need to deploy.” way Bravo. Moments later, the The FAA’s decision to deploy runway status lights over the next three years aims Timing is to further reduce the risk of collision. BY WAYNE ROSENKRANS EVERYTHING U.S. Federal Aviation Administration Aviation Federal U.S. 46 | FLIGHT SAFETY FOUNDATION | AEROSAFETYWORLD | SEPTEMBER 2008 AIRPORTOPS surveillance and cockpit moving-map solu- tions, all still under development. “Until a more comprehensive solution comes along, the FAA and [Los Angeles International Airport (LAX)] are continuing to look at stopgap measures such as runway status lights to improve safety,” said Robert Sturgell, the FAA’s Administration Aviation Federal U.S. acting administrator. “Runway status lights are one way to drive down incursions … one more layer of defense, but [not] the first line of defense.” Reconfiguration of airport runways and taxiways is the highest priority solution for some airports, he said.2 How It Works An RWSL system (Figure 1, p. 48) comprises approach radar, surface radar and transponder multilateration; data processing safety logic; and red lights that communicate runway status. Takeoff hold lights controller — believing incorrectly that the Unlike ASDE-X and the older airport move- at DFW warned two 340 had been issued a position-and-hold ment area safety system (AMASS), RWSL is flight crews about clearance — cleared the flight crew of a not designed for conflict detection, and the aircraft crossing McDonnell Douglas MD80 to cross Run- RWSL display in the airport tower is not a tool Runway 18L/36R way 36R at Taxiway Yankee. The 340 crew for the controller to resolve situations. “With after they received then radioed ATC that, although cleared every operation on a runway — whether there takeoff clearance. for takeoff, they “saw the red lights” of is a conflict or not — RWSL illuminates the red RWSL and therefore did not begin the lights,” Figueroa said. takeoff. The closest proximity of the two For operational use, official details on airplanes was 9,275 ft (2,827 m). RWSL systems at DFW and San Diego appear in the FAA Notices to Airmen (NOTAM). Gen- • ATC cleared the flight crew of a large eral background for pilots has been published commercial transport jet for takeoff, but by Lincoln Laboratory of the Massachusetts the crew rejected the takeoff early in the (U.S.) Institute of Technology — the FAA’s takeoff roll. The FAA said that the captain principal RWSL contractor — on a Web site later reported, “We began to roll, and I <www.rwsl.net>. noticed the RWSL lights. … I aborted the One NOTAM for July 31, 2008 — which takeoff at maximum speed below 80 kt. describes an initial configuration of takeoff I looked down the runway and saw an hold lights (THLs) installed on DFW Run- aircraft crossing the runway left to right … Illuminated runway way 18L/36R — said in part, “RWSL is an [an unspecified Bombardier CRJ- series re- entrance lights automatic, advisory backup system expected gional jet]. I noticed [the red lights] before indicate that to prevent or reduce the severity of runway I saw the intruding RJ. The RWSL worked Runway 9 at San incursions. RWSL conveys the runway occu- — this is awesome. Put them everywhere.” Diego is unsafe to pancy status, indicating when a runway is enter or cross. The FAA’s strategy of applying evolving tech- unsafe to enter [or cross] through the use nology for runway incursion prevention also of in-pavement warning [runway entrance includes the enhanced final approach runway lights (RELs)] and when it is unsafe to take occupancy signal (FAROS), low-cost ground off through the use of in-pavement warning WWW.FLIGHTSAFETY.ORG | AEROSAFETYWORLD | SEPTEMBER 2008 | 47 AIRPORTOPS Runway Status Lights Operational Concept Airport surface detection equipment, THL model X REL RWSL safety logic RIL REL RWSL display for ATC REL REL RIL REL REL REL FAROS REL REL Transponder THL multilateration Airport surveillance radar Not for navigational use RWSL = Runway status lights; REL = Runway entrance lights; THL = Takeoff hold lights; RIL = Runway intersection lights (under development); FAROS = Final approach runway occupancy signal (under development); ATC = Air traffic control Source: U.S. Federal Aviation Administration Figure 1 THLs. The RELs are a series of five off (lights are off) and are switched time, intended to convey approval or red, in-pavement lights spaced evenly automatically based on information clearance to proceed onto a runway or along the taxiway centerline from from the airport surface surveillance to take off from a runway. Pilots remain the taxiway hold line to the runway systems. It is important that transpon- obligated to comply with all ATC edge. … THLs are directed toward the ders be turned on and kept on while clearances, except when compliance approach end of the runway and are taxiing in the movement area so that would require crossing an illuminated visible to pilots in position for takeoff, beacon-based position and aircraft red REL or THL. In such a case, the just commencing departure or on identification data are available to crews should hold short of the runway final approach to land. There are four RWSL .” for RELs or stop the aircraft for THLs sets of THLs, each comprising a series Situational awareness is critical (if possible), contact ATC, and await of 11 red in-pavement lights at 100-ft to the concept. “Pilots should remain further instructions.” [30-m] spacing along the runway clear of a runway when an REL along The NOTAM also covers situations centerline. The four sets of THLs are their taxi route is illuminated,” the in which pilots have begun to enter a operational at the full-length and NOTAM said. “Pilots should not take runway, conduct a takeoff or complete intersection departure positions. off when a THL on the runway ahead is a landing at the moment the RWSL “Status lights have two states: illuminated. Lights that are off convey red lights illuminate. Instructions on (lights are illuminated red) and no meaning. The system is not, at any include taking action according to the 48 | FLIGHT SAFETY FOUNDATION | AEROSAFETYWORLD | SEPTEMBER 2008 AIRPORTOPS pilot’s best judgment of safety when the usual International Interest response is not practical with full understand- The U.S. National Transportation Safety Board ing that red lights indicate the runway is unsafe (NTSB) since July 2000 has urged the devel- to cross or enter, and contacting ATC at the opment of technologies that directly increase earliest opportunity. the awareness of pilots and airfield drivers of collision threats on the ground. The NTSB sup- Unique Airport Configurations ports RWSL as part of an overall response so far Now that RELs and THLs have passed engineer- deemed unacceptable. NTSB member Steven ing tests and met human factors performance cri- Chealander said, “Direct warning is crucial teria, the RWSL systems at DFW and San Diego because it gives both controllers and those are being completed, and all the other airports operating the aircraft increased time to react. … will install RELs on some or all taxiways and [NTSB] investigations have found that AMASS/ THLs on one or both ends of some or all runways ASDE-X are not adequate to prevent serious under the FAA’s schedule and budget for RWSL runway collisions because too much time is lost deployment. routing valuable information through air traffic “The FAA approved delivery of RELs and control. … All of the runway incursion preven- THLs in some mixture to [all] 22 airports,” tion technology being developed and tested by Figueroa said. “Some airports need RELs at the FAA that would give a direct warning to the every intersection of every runway.

Load more