The Federal Aviation Administration today warned operators of the Boeing 767-300 not to neglect recommended maintenance of the aircraft's engine thrust reverser.
But the FAA said that while it has been confirmed that the thrust reverser on the number one engine of the Austrian airliner that crashed in Thailand on May 26 was fully deployed, there are still "too many unknowns" to link that to the accident.In a letter to aviation authorities in countries worldwide, the FAA said that the investigation of the crash of the Lauda Airlines Boeing 767-300 "has not yet revealed the events which led to the in-flight deployment."
A cockpit recording showed that immediately before the crash the crew was struggling to interpret warning signals related to a reversal in engine thrust.
Thrust reversers are used to slow an aircraft during landing but are not used in flight.
"We are working with the manufacturer to define and explore scenarios which could explain the accident events," the FAA said.
But it said further analysis and examination of the wreckage "must be conducted before any conclusions are drawn."
The FAA said there is nothing in the flight history of the Boeing-767 to indicate any problems with the thrust reverser system. One known incident was found to be related to improper maintenance, it said.
The aviation agency emphasized that Boeing has advised all operators of the model 767 aircraft of the importance of following existing maintenance procedures, including assuring that any faults are identified and corrected before the airplane is released for service.