The Piper PA-15 was parked at Fishburn, County Durham. After refuelling, it was pushed away from the bowser and turned…

The Piper PA-15 was parked at Fishburn, County Durham. After refuelling, it was pushed away from the bowser and turned through 90� so that the engine could be started. The control stick was lashed in the fully aft position and both mainwheels were chocked so that the pilot could start the engine by hand-swinging the propeller without assistance from anyone in the cockpit.

The engine proved difficult to start. For each attempt the throttle was set about 3�4 inch open with the throttle friction at a loose setting. When the engine did fire it accelerated to an abnormally high speed. The pilot tried to dash around the right wing to reach the throttle but as he did so the left mainwheel rode over its chock.

The aircraft swung to the right until it was no longer restrained by the chock beneath the right mainwheel and accelerated towards the windsock mast, with the pilot still trying to enter the cockpit. The left wing struck the mast, pivoting the aircraft around the mast and accelerating the engine. The pilot stepped clear, but soon found the aircraft coming back towards him.

The aircraft turned, missing the pilot, but struck one corner of the fuel bowser with its right wing, propeller and landing gear. The blade strikes penetrated the bowser and the impacts were sufficient to stop the engine rotating. There was no fire, but as the pilot caught up with the aircraft and grabbed the cockpit fire extinguisher, he noticed that the throttle had moved to a high power setting.

After the accident the pilot discovered a copy of a fax message which had been sent to another syndicate member. This included a line stating that the throttle linkage had a tendency to vibrate towards the full power position unless the throttle friction nut was tight. This information had not, apparently, been copied to all syndicate members. The pilot also attributed the accident to two other factors: the ground was soft, making it easier for the aircraft to overrun the chocks, and he had not expected the engine to start so vigorously.