Following a 50-hour check, the aircraft’s ignition switch was left in the RIGHT position, with no key in the switch, due to the use of an incorrect key. During the next pre-flight inspection the pilot perceived that the ignition switch was in the OFF position. As he turned the propeller by hand, as required by the aircraft’s EXTERNAL INSPECTION checklist, the engine started and ran at full power. The aircraft broke free of its tie-downs, struck a parked aircraft and crashed into an earth embankment. Safety action has been taken concerning the content of the aircraft’s flight manual and service manual checklists.
Air Accidents Investigation: Beagle B121 Series 1 Pup, G-AXPM