What happened
On 10 July 2020, a Reims Cessna F150M, registration G-CSBM, was conducting a private flight from Blackbushe Airport to Sandown Airport on the Isle of Wight. The flight involved the pilot and one passenger. During the return leg, as the aircraft was approximately 2 nm from Blackbushe, the engine began to cough and lose power while the pilot was descending to circuit height.
Recognising the potential for total engine failure, the pilot opted for a precautionary landing in a nearby large grass field. The pilot executed a 18 and 0-degree turn to position the aircraft for a base leg and landed using full flaps. The landing resulted in no injuries to the occupants and no damage to the aircraft.
The investigation
The AAIB investigation established that the engine power loss was caused by fuel exhaustion. Prior to departure from Blackbushe, the pilot attempted to obtain a more precise fuel measurement than the aircraft's standard wooden dipstick could provide. To achieve this, the pilot used a different dipstick featuring a more detailed scale, which he believed to be more accurate.
However, this specific dipstick was calibrated for a Cessna 172 rather than the Reims Cessna F150M. This error led the pilot to significantly overestimate the amount of fuel available for the return journey. Furthermore, while the pilot chose not to rely on the aircraft's fuel gauges due to a general belief in their unreliability, the aircraft owner noted that the gauges on G-CSBM were actually reasonably accurate and likely would have indicated the low fuel state.
Findings
- The engine lost power because the aircraft ran out of fuel.
- The pilot used a fuel dipstick that was not calibrated for the specific aircraft type.
- The use of the incorrect tool caused the pilot to believe there was more fuel onboard than was actually present.
- The pilot's decision to perform a precautionary landing before the engine failed completely prevented a more serious accident.
Safety action
- The flying club has issued a reminder to all pilots regarding the necessity of using only the fuel dipsticks specifically calibrated for the aircraft they are operating.