Nother skid
Jet's skid off runway highlights pilot complacency on automation
June 6, 2012 - 1:20PM
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Brake system failures combined with human error led to an American Airlines jetliner skidding off a runway in Wyoming, the US National Transportation Safety Board said.
The flight from Chicago's O'Hare International Airport to Jackson Hole Airport on December 29, 2010, overshot the end of the 1.9km runway into a snowy field after landing. None of the 179 passengers and 6 crew members aboard the Boeing 757 were injured.
The incident highlights an issue that has arisen in recent accidents around the world: today's automated, reliable aircraft can breed complacency in pilots, the NTSB concluded.
A simultaneous series of events aboard the jetliner prevented its braking systems from functioning, the investigation found. The pilots, distracted by the initial failures, could have stopped the plane had they manually deployed some of those systems, the agency concluded.
"This incident demonstrates that experienced pilots can become distracted during unusual events," Katherine Wilson, an NTSB investigator who specializes in human performance, said.
The pilots attempted to switch on thrust reversers, devices that use engines to help a plane stop, after touchdown. The plane's computers prevented them from working, the investigation found. Pilots interviewed after the accident didn't know about the issue, the investigation found.
Panels on top of the wings known as speedbrakes, which flip up upon touchdown, also didn't work, the safety board found. Brakes are ineffective without those panels, which force a plane's wheels to the ground.
The captain on the flight erroneously called out that the speedbrakes were working, according to the NTSB. The plane could have stopped safely if the pilots had manually switched on the speedbrakes, the investigation found.
As jets have become more computer-driven, pilots spend more time monitoring autopilots and other systems, NTSB Chairman Debbie Hersman said in an interview after the hearing.
"That monitoring is no less important than the hand flying they once did, and failing to be attentive to the monitoring can be just as catastrophic," Hersman said.
The pilots landing in Jackson Hole, distracted by the thrust-reverser failure, didn't follow American's direction to check whether things such as speedbrakes are working, the NTSB concluded.
The NTSB voted to recommend that all airlines develop new training on the importance of monitoring speedbrakes. A review of incident reports by the safety board found 11 cases in which the speedbrakes activated and then deactivated on their own.
The board also recommended that a warning horn be installed on jets to alert pilots if the speedbrakes are not working. The board doesn't have authority to implement changes on its own.
Bloomberg/SMH
Last edited by Rollingthunder; 6th Jun 2012 at 11:13.