What happened
On June 9, 2011, a Cessna F152 was conducting a cross-country training flight when the engine lost power during the final approach to Aeroclub Keiheuvel. The flight, which included stops at several airfields, was intended to prepare a student pilot for a long-distance navigation exercise.
As the aircraft entered the base leg of the landing circuit, the engine began to fluctuate and eventually stopped entirely. At approximately 650 feet AGL, the instructor determined that the aircraft lacked the necessary altitude and airspeed to reach the runway, particularly due to a heavy upwind component and the proximity of trees along the flight path. The instructor opted to execute an emergency landing in a nearby field. During the maneuver, the aircraft struck the ground, crossed a road and several ditches, and the nose landing gear eventually collapsed, causing the plane to flip over. The two occupants escaped the wreckage, with the student pilot sustaining a minor facial injury.
The investigation
The AAIU(Be) examined the flight history, maintenance records, and fuel management practices. The investigation focused on why the engine failed during the final leg of the flight. Investigators reviewed the pre-flight procedures at the home base, noting that the student pilot relied on cockpit fuel quantity indicators rather than a visual inspection of the tanks.
Technical analysis of the fuel gauges revealed that these indicators are notoriously unreliable and non-linear, often providing inaccurate readings when tanks are near full. The investigation also looked into the flight's fuel consumption, noting that the total flight time had exceeded initial estimates, which increased the risk of running dry.
Findings
- The primary cause of the accident was fuel exhaustion, which resulted in the loss of engine power.
- The aircraft began the flight with insufficient fuel on board.
- The pre-flight inspection was incomplete because the crew did not perform a visual check of the fuel tanks.
- The fuel quantity indicators provided an inaccurate representation of the actual fuel remaining.
- The aircraft was in an airworthy condition and had been properly maintained.
Safety action
To prevent similar occurrences, the AAIU(Be) recommended that Aeroclub Keiheuvel provide a calibrated dipstick for each aircraft type to allow for accurate visual fuel level verification and to train all pilots in its use.