What happened
On 5 January 2014, a Bat Hawk aircraft, registration ZU-FXI, was conducting a private scenic flight departing from Andrew’s Field. While cruising at approximately 600 feet above ground level, the aircraft suffered a sudden loss of engine power. The pilot attempted to execute a forced landing, aiming for a beach area near Suiderstrand. However, the descent rate was too steep, and the aircraft was unable to clear a patch of fynbos bush. The impact with the terrain caused substantial damage to the nose section, the right wing, the keel bar, and the undercarriage. Both the pilot and the passenger escaped the wreckage without any injuries.
The investigation
SACAA AIID investigators examined the wreckage and the engine's maintenance history. Testing revealed that the engine failed when the electrical fuel booster pump was deactivated. Specifically, when the mechanical fuel pump was the sole source of fuel delivery, the engine failed within 20 to 30 seconds. Upon dismantling the mechanical pump, investigators discovered a dislodged one-way valve, which had disrupted the fuel flow.
Further scrutiny of the engine's history revealed that the unit had previously been part of an aircraft, ZU-EAX, which was lost at sea in 2011. The engine had been recovered from the ocean and rebuilt without the knowledge of the authorities. Additionally, while the pilot performed regular maintenance, they were not qualified to perform such work under existing regulatory procedures, and the investigation concluded that the valve failure likely occurred during an improper assembly during a previous service or installation.
Findings
- The primary cause of the engine failure was fuel starvation resulting from a dislodged one-way valve in the mechanical fuel pump.
- The electrical booster pump was not functioning at the time of the engine failure.
- The pilot switched off the electrical booster pump at an altitude (600 feet) below the recommended safety threshold of 1,500 feet.
- The aircraft's descent rate during the forced landing attempt was too high to avoid the vegetation.
- The engine had been previously submerged in saltwater and rebuilt without proper regulatory notification.
- Maintenance on the fuel pump was performed by an unqualified individual.