Australian-owned company Government Aircraft Factories (GAF) manufactured the Nomad aircraft which crashed in Sembulan, Kota Kinabalu, on June 6, 1976, claiming the lives of then Sabah chief minister Fuad Stephens and 10 others.
GAF sent its acting chief designer, David Hooper, and chief test pilot Stuart Pearce to Sabah to assist in the Malaysian investigation into the crash, and they both signed off on the GAF report which the Australian government declassified yesterday.
The duo died during a GAF N24 Nomad test flight in Victoria, Australia, on Aug 6, 1976, exactly two months after the Double Six tragedy.
Their identities were only made public when the GAF report was declassified yesterday, following the declassification of a similar report by the Malaysian government earlier this month.
Pearce was piloting the test flight while Hooper was on board as an observer.
Pearce was killed in the crash, while Hooper, who was occupying the other pilot’s seat, sustained injuries which resulted in his death two days later.
Also on the flight was flight test engineer Philip Larcey, who was seriously injured.
In its report on the incident sighted by FMT, Australia’s Air Safety Investigation Branch said that Pearce and Hooper’s post mortem examinations indicated that both died as the result of injuries received during the impact of the aircraft with the ground.
“There was no evidence of pilot incapacitation or that his health was in any way impaired prior to, or during, the flight,” said the report.
The report also said the crash was due to the “simplified design criterion which was used to justify freedom from flutter during the flight testing of various tailplane modifications, which was not valid for a design which included tab trailing edge T-strips”.
It noted that the test flight was meant to determine how the plane would operate after modifications had been made to it, adding that this was the first flight after full-span trim tabs with trailing edge T-strips had been fitted to the tailplane.
The report said Pearce was “appropriately qualified and licensed”, and the aircraft was appropriately maintained and certified, and loaded within safe limits. Weather conditions were also not a factor in the accident.
In their report into the Double Six crash operated by Sabah Air, Pearce and Hooper said the airline was operating illegally as the then civil aviation department (CAD) had not approved the draft of its operations manual.
Like the Malaysian report on the crash, their report also ruled out fire or sabotage as probable causes for the incident, pointing out that a preliminary investigation found overloading at the back of the aircraft to be the cause.