What happened
On the morning of 25 February 2022, a student pilot was conducting a solo cross-country navigation flight in a Cessna 172I, registration ZS-FIF. The flight, part of a Part 141 training program, originated from Lanseria International Aerodrome (FALA) and included several intermediate stops at Brits, Warmbaths, Pilanesberg, and Rustenburg aerodromes.
While on final approach to Runway 07 at FALA, the pilot experienced engine roughness followed by a complete engine stoppage. Despite attempting to restart the engine, the pilot was unable to restore power and declared an engine failure to air traffic control. The pilot subsequently executed a forced landing in an open field located approximately 1.1 nautical miles from the runway threshold. During the landing, the aircraft struck a hidden 40-centimeter-high embankment. The impact caused the nose wheel to detach, leading the aircraft to nose over and come to rest in an inverted position. The pilot sustained facial lacerations and a shoulder strain, primarily caused by a portable fire extinguisher that broke loose from its mount during the impact.
The investigation
SACAA AIID examined the circumstances surrounding the engine failure and the subsequent impact. Investigators reviewed the aircraft's maintenance history, noting that the last inspection had occurred roughly 34 flight hours prior to the accident. An engine ground run conducted after the aircraft's recovery showed no mechanical defects or anomalies that would prevent normal operation.
Furthermore, investigators analyzed the weather conditions and the aircraft's configuration. While the surface weather was stable, the carburettor icing-probability chart indicated that conditions conducive to serious icing were present during the descent. The investigation also looked into the physical state of the aircraft's cockpit, specifically the position of the carburettor heat control.
Findings
- The engine failure was highly likely caused by carburettor icing, as the carburettor heat lever was found in the 'COLD' position during the on-site inspection.
- The aircraft's nose gear failure and subsequent inversion were caused by the collision with a concealed embankment during the forced landing.
- The pilot's facial injuries were a direct result of the portable fire extinguisher detaching from its bracket during the aircraft's inversion.
- The flight was a legitimate, authorized training mission, and the aircraft was within its airworthiness limits with sufficient fuel on board.