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Date:Friday 30 August 1957
Type:Silhouette image of generic TPIN model; specific model in this crash may look slightly different
Scottish Aviation Twin Pioneer 1
Registration: JZ-PPX
MSN: 509
First flight: 1957-06-05 (3 months)
Engines: 2 Alvis Leonides 514
Crew:Fatalities: 2 / Occupants: 2
Passengers:Fatalities: 0 / Occupants: 0
Total:Fatalities: 2 / Occupants: 2
Aircraft damage: Damaged beyond repair
Location:13 km (8.1 mls) off Japen Island (   Papua New Guinea)
Phase: Maneuvering (MNV)
Departure airport:Biak-Mokmer Airport (BIK/WABB), Indonesia
Destination airport:Biak-Mokmer Airport (BIK/WABB), Indonesia
Twin Pioneer JZ-PPX took off from Mokmer at 09:30 for a local training flight. Takeoffs and landings were practiced and after some time the captain requested and received permission to carry out manoeuvres outside the circuit. During one of these manoeuvres, a right-hand turn, the right wing broke off. The aircraft lost control and spiralled down into the sea. The wreckage stayed afloat for a while and sank.

Probable Cause:

PROBABLE CAUSE: "The Commission is of the opinion that, on the ground of the available evidence of the accident with the Twin Pioneer G-AOEO, the accident with the JZ-PPX has to be put down with to certainty nearing probability to the failure of the V-brace strut due to fatigue, because both aeroplanes were equipped with the same type of liftstrut and V-brace construction and because both aeroplanes were used in the same manner. The JZ-PPX carried out many instruction flights at a low altitude, many take-offs and landings, many manoeuvres with high flight loads, possibly up to the maximum loads. The G-AOEO also carried out many demonstration flights at a low altitude with man take-offs and landings, many manoeuvres, also with possibly maximum loads. The term of life of the V-brace as declared by the manufacturer, was based on conditions of flight which are not in agreement with the reality. During a meeting at September 6, 1957, Mr MacCallum of Scottish Aviation Ltd. gave a value of 4000hrs which raised a discussion. The Commission is aware of the fact that he cannot give a positive opinion upon the cause of the accident because there are no silent witnesses present, but nevertheless is of the opinion that there is a close conformity with the accident of the G-AOEO."

Wing failure
Loss of control

» NRC Handelsblad Overzeese Weekeditie xx.09.1958 (p.11)


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This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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