Crash of a Pilatus PC-6/B2-H2 Turbo Porter in Annemasse

Date & Time: Jun 26, 2001 at 1705 LT
Operator:
Registration:
F-GUAS
Survivors:
Yes
Schedule:
Annemasse - Annemasse
MSN:
557
YOM:
1963
Country:
Region:
Crew on board:
1
Crew fatalities:
Pax on board:
0
Pax fatalities:
Other fatalities:
Total fatalities:
0
Captain / Total flying hours:
919
Captain / Total hours on type:
520.00
Aircraft flight hours:
13000
Circumstances:
The pilot took off from Annemasse Airfield with nine skydivers on board. After dropping them at FL125, five to six seconds after initiating the descent, he felt strong vibrations. He reduced speed and saw the right out aileron separating from the wing. The pilot managed to maintain control of the aircraft by keeping the stick fully to the right and used the rudders to return to his departure aerodrome. He landed the airplane on the grass near the paved runway 30. During a hard landing, the right main landing gear broke off and damaged the fuselage. The pilot escaped uninjured while the aircraft was damaged beyond repair.
Probable cause:
The accident was due to the loss of the right outboard aileron in flight. This loss was probably following the crack noticed by the pilot at the base of the right aileron balancing weight, which would have propagated in flight and would have then leads to tearing off the balancing weight. The accident resulted from the club pilots' decision to continue flying despite they have noticed the crack and that the manufacturer had advised them to stop flights.
Final Report: