Incident Overview
A person sustained a propeller strike while preparing to hand-prop an aircraft engine. The pilot reported that the cranking power of the airplane's battery was diminished because the airplane had been parked outside for an extended period in below-freezing temperatures. Unable to start the engine using the electric starter, the pilot and the individual attempted to hand-prop the engine.
Pilot Actions
At the time of the accident, the pilot was seated in the airplane operating the engine controls. The pilot stated that the magnetos were off and the mixture lever was positioned at idle-cutoff. These actions are consistent with preparing the engine for hand-propping.
Sequence of Events
As the individual positioned the propeller for maximum leverage, the propeller "snapped back" due to cylinder compression and struck the person in the head. The source does not specify the extent of injuries or any further medical outcomes.
Contributing Factors
The source indicates that the diminished battery power due to cold temperatures led to the inability to start the engine electrically, prompting the hand-prop attempt. No other causal factors are identified.