What happened
Shortly after initiating takeoff, the aircraft experienced a loss of partial engine power. The pilot attempted to return to the airport for a relanding; however, the engine subsequently lost all power completely. This necessitated an emergency landing in a nearby field.
The investigation
Post-accident inspection of the engine revealed that one spark plug was loose. The remaining spark plugs were found to be severely fouled with lead and carbon deposits. Despite these conditions, the engine was successfully test-run after the accident occurred.
Findings
The primary mechanical issues identified were a loose spark plug and severe lead and carbon fouling of the remaining plugs. These conditions contributed to the partial and subsequent total loss of power during the critical takeoff phase.