DHC-3 Otter Archive Master Index

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c/n 92

55-3252
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Photo:

c/n 92

55-3252

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• 55-3252 United States Army on 14th February 1956. Designated U-1A

It was allocated that day to the 14th Army Aviation Company, Fort Riley, Kansas whose personnel were at Downsview training on the Otter.

Accident: Downsview, ON 14-Feb-1956. The Otter took off from runway 15 at Downsview at 1521 hours and crashed near Keele Street seventeen minutes later, sadly killing all on board. The Otter had broken up in mid air, the port wing failing and striking the tailplane. It transpired that a defective valve was to blame, causing the flaps to retract involuntarily. The resulting download, with the tailplane setting as it was, brought about the failure of the wings.

Destroyed

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Otter 92 was delivered to the United States Army on 14th February 1956 with serial 55-3252 (tail number 53252). It was allocated that day to the 14th Army Aviation Company, Fort Riley, Kansas whose personnel were at Downsview training on the Otter when 53252 was delivered. It was intended that the Otter remain at Downsview for some weeks, while the training took place, before it was to set off for its new home. Sadly however the Otter was to crash on the very day it was handed over to the Army.

On 14th February 1956 three Otters had been allocated to the training of Army aviators, including 53252. The flights were intended as orientation and familiarisation flights. Flying 53252 that day was a DHC training pilot Bill Ferderber and there were three US Army personnel on board, all of the 14th Aviation Company, including the Company Commanding Officer, Major Aaron G. Atkinson. The Otter took off from runway 15 at Downsview at 15:21 hours and crashed near Keele Street seventeen minutes later, sadly killing all on board. The Otter had broken up in mid air, the port wing failing and striking the tailplane.

The initial investigation placed the blame on the Otter flying through the wake of a jet aircraft, but when an exactly similar accident befell an RCAF Otter (aircraft number twelve) two months later, the circumstances were examined again. It was determined that structural failure had resulted from a sudden and unexpected flap retraction which, together with the tailplane trim setting, had presented the aircraft with a complete out-of-trim configuration. The flaps could only be moved by being handpumped because they were hydraulically locked by a ratchet valve. It transpired that a defective valve was to blame, causing the flaps to retract involuntarily. The resulting download, with the tailplane setting as it was, brought about the failure of the wings.

Full history courtesy of Karl E. Hayes © from DHC-3 Otter: A History (2005).

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