What happened
On 12 March 2022, a private flight departing from Warmbaths Aerodrome (FAWA) in Limpopo Province experienced a critical engine failure. The aircraft, a Kitplanes Safari LSA with registration ZU-ING, was being operated for a recreational flight intended to tour the Limpopo River. Approximately 90 minutes into the flight, while cruising at 3,000 feet AGL over the Zingela Nature Reserve, the pilot and passenger noticed fuel leaking into the cockpit. Shortly thereafter, the engine stopped.
In an attempt to restore power, the pilot activated the auxiliary fuel pump and attempted a restart, but the engine remained non-functional. Noticing fuel on the windshield, the pilot deactivated the fuel selector and the auxiliary pump to mitigate the leak. While searching for a landing site, the pilot identified an open field but encountered power lines in the flight path. A maneuver to avoid the lines resulted in the aircraft striking a tree, which caused the left wing to collapse and the aircraft to impact the ground. A post-impact fire, fueled by leaking aviation gasoline, consumed the aircraft. Both occupants sustained serious burn injuries and required medical evacuation.
The investigation
SACAA AIID investigators examined the wreckage and the fuel system to determine the cause of the engine stoppage. While the fuel lines and clamps were found to be intact and properly installed, the investigation focused on the auxiliary fuel pump assembly.
Upon disassembly of the pump, investigators discovered that the outlet nipple of the high-pressure side of the auxiliary fuel pump had detached. The nipple showed evidence of nicks and cracks. Furthermore, the fuel hose in that area exhibited signs of fuel being blown outward under pressure. The investigation looked into whether a manufacturing flaw or an improper crimping process had weakened the plastic outlet.
Findings
- The primary cause of the engine failure was fuel starvation resulting from a leak in the engine compartment.
- The high-pressure outlet of the auxiliary fuel pump had a crack or structural damage, which allowed fuel to escape the system.
- The attempt to restart the engine using the auxiliary fuel pump likely exacerbated the leak by increasing pressure in the compromised component.
- The post-impact fire was triggered when leaking fuel came into contact with hot engine surfaces during the forced landing sequence.
- It is possible that the pressure outlet pipe was not properly supported during assembly, leading to the initial structural failure of the nipple.