Airservices Australia is redesigning the non-precision approach for the runway at Lockhart River, the remote Queensland airport where an aircraft crashed in 2005 killing all 15 on board.
The Australian Transport Safety Bureau (ATSB) says following the May 2005 crash several airlines have told the bureau that when their aircraft approaches the Lockhart River runway the ground proximity warning system (GPWS) on the aircraft "produces a warning even when the aircraft is not actually at risk of conflict with the terrain."
The ATSB says "the GPWS warnings have been confirmed by both simulation and experience to be nuisance alerts and, as such, do not provide a true warning that the aircraft is in potential conflict with the terrain."
"Nuisance warnings occurring while maintaining an approach profile, could condition flight crews to ignore such warnings in order to complete the procedure, rendering the warning device ineffective," it says.
It adds, if an aircraft was below the approach profile or off-track and the pilot chose to ignore the GPWS - thinking it was a nuisance warning - then ultimately it could lead "to a controlled flight into terrain," it adds.
The aircraft in the May 2005 crash, that killed all 15 on board, had no ground proximity warning system.
But following the crash, Australia implemented new regulations requiring all aircraft to be fitted with a terrain awareness and warning system.
The ATSB says the Civil Aviation Safety Authority (CASA) told the bureau it would support Airservices Australia "in the design and approval of the Lockhart River runway 12 RNAV [area navigation] non-precision approach."
It says CASA has purchased some equipment that is being fitted to a Cessna Conguest for use in the approach validation and that the new design for the approach "is expected to be validated in early August".
Source: Air Transport Intelligence news
