Incident Overview
A certified flight instructor (CFI) and a student pilot experienced a complete loss of engine power during a training flight. The CFI had hand propped the engine before departure, and the student had set the engine controls. The flight involved practicing ground reference maneuvers and slips. At an altitude of approximately 700 feet above ground level, the engine lost all power and the propeller stopped spinning.
Emergency Response
The CFI performed the emergency checklist from memory and identified a frozen lake as a suitable landing site. During the landing roll, the airplane nosed over after traveling about 30 feet, resulting in substantial damage to the wooden wing spars.
Post-Accident Examination
Photographs taken at the accident site showed that the fuel primer control was unlocked and positioned at an intermediate setting. The CFI reported that the student had stated he locked the primer control but only turned it about one-eighth of an inch. The CFI had checked the primer control before the flight and confirmed it was in the locked position. The investigation could not determine how the primer control became unlocked.
During a post-accident examination, the engine was started and ran normally. When the primer control was placed in the position found after the accident and the engine power was reduced to 1,000 rpm, the engine lost all power. The airplane was not equipped with an electrical system, preventing an in-flight restart.