What happened
On 28 January 2014, a KR-2S aircraft, registration ZU-DVP, departed from runway 11 at Wonderboom Airport (FAWB) for a test flight intended to verify the aircraft's airworthiness for an upcoming sale. Shortly after takeoff, the pilot attempted to broadcast an emergency Mayday call to the air traffic controller, but the transmission was never completed.
Air traffic control observed the aircraft banking sharply to the right of the runway. Moments later, the aircraft struck the ground at a steep angle, with the leading edge of the right wing tip making first contact. The impact was severe, causing the aircraft to flip onto its back and slide along the terrain, breaking apart into several pieces. The pilot sustained fatal injuries, and the aircraft was destroyed.
The investigation
SACAA AIID investigators examined the wreckage and the engine, which was a modified Volkswagen 2.4L Turbo unit. The investigation focused on the engine's performance and recent maintenance history. It was noted that the aircraft had experienced an engine failure just days prior, and the pilot had been involved in recent maintenance and ground runs on the same powerplant.
Technical inspections of the engine revealed significant irregularities. Investigators found that the engine had been subject to unauthorized modifications and poor maintenance practices. Specifically, the investigation looked into the fuel delivery system and the physical condition of the internal engine components, such as the bearings and the fuel pump.
Findings
The investigation established that the primary cause of the accident was engine failure immediately following takeoff. Several critical contributing factors were identified:
- Fuel Starvation: The engine was fitted with an incorrect fuel pump that did not meet manufacturer specifications. This was compounded by a modified fuel pump shaft that had been improperly extended via welding.
- Poor Workmanship: The engine overhaul and modification processes were characterized by substandard practices. This included the use of excessive silicone during assembly, which likely blocked oil return passages, and the use of improperly machined bearings.
- Maintenance Deficiencies: Evidence of excessive wear was found on components despite the engine having only operated for approximately 3.38 hours since its last overhaul. The investigation also noted that certain oil channel plugs had been welded shut, preventing proper inspection and cleaning.
- Unapproved Modifications: The engine had undergone significant structural and mechanical changes to adapt a automotive engine for aviation use, without adequate documentation or evidence of approved engineering standards.