What happened
On September 3, 2018, a C-180 H aircraft, registration N8SQ, was performing a local flight departing from and returning to La Côte (LSGP). While executing a standard left-hand turn over Lake Joux at an altitude of approximately 4,500 feet, the pilot experienced a sudden loss of engine power. Following established emergency procedures, the pilot transmitted a distress message on the Geneva Information frequency and performed a precautionary landing in an uphill field near Le Chenit, Vallée de Joux.
The investigation
Following the landing, the pilot inspected the aircraft and found no structural damage. Upon inspection of the fuel levels, it was noted that the fuel quantity was extremely low. The pilot was able to successfully restart the engine on the ground. The investigation focused on why the fuel levels were insufficient for the planned flight.
Findings
- The aircraft is a conventional gear design where fuel gauges are notoriously imprecise, making visual estimation of fuel levels on the ground difficult.
- To compensate for this inaccuracy, a fuel totalizer had been installed by the owner.
- During the most recent refueling, a different pilot erroneously entered the fuel volume in gallons instead of liters into the totalizer.
- This data entry error resulted in a significant discrepancy between the recorded fuel amount and the actual fuel remaining in the tanks, leading to the unexpected power loss.