What happened
The pilot of an Aeronca 15AC had intentionally flown the aircraft with less fuel than usual. This decision was driven by the combined weight of the passengers and their cargo, which likely impacted the aircraft's performance or range calculations. However, the pilot lacked sufficient familiarity with the specific fuel indicating system installed in this model. Because of this knowledge gap, he was unable to accurately determine the exact quantity of usable fuel remaining in the tanks.
As the flight progressed toward its destination, the aircraft entered the downwind leg of the traffic pattern. At this stage, fuel exhaustion occurred due to the earlier miscalculation and lack of precise monitoring. With no power available, the pilot was forced to execute a forced landing. The terrain selected for the landing was unsuitable, contributing to the severity of the incident.
The investigation
The investigation focused on the operational decisions made prior to the flight and the pilot's interaction with the aircraft's systems during the approach phase. Examination of the fuel system revealed no mechanical failures or leaks that would have caused unexpected loss of fuel. The primary issue was identified as a discrepancy between the fuel quantity indicated and the actual usable fuel available, exacerbated by the pilot's inability to interpret the gauge correctly.
Findings
Several contributing factors were identified in this accident:
- Fuel management error: The pilot chose to carry less fuel than necessary due to weight constraints without adequately compensating for the reduced margin of safety.
- Instrument familiarity: The pilot was not fully familiar with the Aeronca 15AC's fuel indicating system, leading to an inaccurate assessment of remaining fuel reserves.
- Terrain selection: The forced landing was conducted in unsuitable terrain, which likely increased damage and risk to occupants.
The sequence of events clearly points to a failure in pre-flight planning and in-flight monitoring of fuel status. The pilot's lack of experience with the specific aircraft type's instrumentation played a critical role in the outcome.