DOT Auditing Runway Incursions
Despite the installation of runway collision avoidance equipment at many of the nation’s largest airports, recently there has been an increase in the number and severity of runway incursions at three major airports.
During the 18-month period between Oct. 1, 2004 and April 1, 2006, Boston Logan had 18 incidents (one severe), Chicago O’Hare had 12 incidents (three severe) and Philadelphia had 13 incidents (one severe involving a collision). They were the highest number of runway incursions at the nation’s large commercial airports.
The Department of Transportation’s inspector general has launched an audit to assess the actions the FAA has taken to identify and correct the causes of recent runway incursions at the three airports and address those issues that could affect safety system-wide.
“One of the primary indicators of the safety of the National Airspace System is runway incursions,” the DOT IG said. “Reducing runway incursions is a key performance goal for the [FAA] that requires attention at all levels of the agency.”
The IG noted that the FAA has been making progress in reducing runway incursions. The total number of runway incursions decreased from a high of 407 in Fiscal Year 2001 to 327 in FY2005, and the most serious incidents decreased from 53 to 29.
The runway incursion issue has been on the NTSB’s “Most Wanted” list since its inception in 1990. In the late 1980s an inordinate number of runway incursions/ground collision accidents resulted in substantial loss of life, and the Safety Board issued numerous safety recommendations addressing the issue.
While the FAA completed action on a number of important objectives to make ground operation of aircraft safer, the Safety Board said these incidents continue to occur with alarming frequency.
Ground Safety Equipment
For large airports, the FAA has completed installation of the airport movement area safety system (AMASS) at 34 sites. The agency has also developed and is installing the airport surface detection equipment model X (ASDE-X) at 25 mostly medium-size airports but also at Boston and O’Hare.
AMASS is a radar-only conflict detection and alerting system. ASDE-X builds on AMASS by adding diverse sensors and enhanced tracking. “Initially, the FAA reported it would have 34 ASDE-X systems installed by 2007,” the NTSB said, “but recent reports show the delivery dates have been pushed back indefinitely as a result of several factors, including budget reductions.”
Both systems provide warnings to controllers of potential ground collisions. Neither provides warnings to the cockpit. The system the FAA currently is deploying requires that a controller determine the nature of the problem, pinpoint the location, identify the aircraft involved, decide what action to take and issue appropriate warnings or instruction.
Simulations of AMASS performance using data from actual incursions show that alerts may occur as little as eight to 11 seconds before a potential collision–providing no margin for error. In three recent incidents–at Boston last June, New York last July and Las Vegas last September–AMASS did not alert controllers in time to be effective.
In the incident at Boston Logan, an Aer Lingus A330 and a US Airways 737 came within 171 feet of each other on an intersecting runway after both were cleared for takeoff. The 737 pilot, who saw the potential hazard, pushed the control column forward, keeping the aircraft on the ground while the Airbus passed overhead. The 737 took off farther down the runway.
In the incident at JFK International, there was a near collision between an Israir 767 and an Airborne Express DC-8 freighter. The passenger jet entered a runway on which the freighter was on its takeoff roll. It is estimated that the freighter cleared the 767 by about 100 feet as it took off over the 767.
In the incident at Las Vegas International Airport, there was a near collision between an Air Canada A319, which had just landed, and an America West A320, which was cleared to take off. The controller confused two departure aircraft and cleared the Air Canada jet to cross a runway as the A320 was taking off. The America West pilot reported that he was 100 feet above the Air Canada jet as he passed over it.
Crew Warnings Needed
Although the FAA has an active program to reduce runway incursions and prevent ground collisions, the NTSB is concerned that this system relies primarily on the controller to communicate with flight crews to prevent a ground collision. The Board believes there should be direct warnings to flight crews.
“Until there is a system in place to positively control ground movements of all aircraft, with direct warning to pilots, the potential for this type
of disaster will continue to be high,” the NTSB said.
The FAA told the Safety Board that it has reviewed the technical performance of potential ground movement safety systems at some airports not scheduled for ASDE-X or AMASS. The FAA is considering two of these solutions, which prevent runway incursions by providing a direct warning to flight crews, for functional and operational testing in an airport environment.
In addition to AMASS and ASDE-X, the FAA is developing several technologies at various airports. One is a final approach runway occupancy signal that will flash the precision approach path lights to warn pilots on final approach when another machine is on the runway.
Another system under development is the enhanced airfield lighting system, which will improve the conspicuity of hold lines and reduce the likelihood of pilots inadvertently entering a runway. Runway status lights would be used to warn pilots and other airport vehicle operators that it is unsafe to enter a runway.
“While these technologies might offer added safety by providing information directly to cockpit crews,” the NTSB said, “they are many years away from possible implementation.”