What happened
On the afternoon of 13 June 1999, a student pilot prepared for a solo training flight departing from Nelspruit Airport. Following a standard pre-flight inspection and completion of necessary documentation, the pilot departed from runway 22. During the initial takeoff roll and subsequent climb, the pilot reported that while airspeed initially appeared normal, the airspeed indicator subsequently dropped to zero.
After notifying the control tower of the instrument failure, the pilot executed a teardrop maneuver with the intention of returning to land on runway 04. During the approach, the pilot was noted to be at an excessive altitude and speed, positioned very close to the runway. As the C172, registration ZS-NWG, attempted to land, the aircraft underwent approximately six porpoising motions. This instability resulted in the collapse of the nose landing gear, causing the aircraft to skid to a stop roughly 30 meters from a parked airliner.
The investigation
The investigation focused on the sudden loss of airspeed indication and the subsequent loss of control during the landing phase. Investigators examined the aircraft's pressure instruments to identify any mechanical or systemic failures. However, testing of the instrumentation following the event revealed no evident malfunctions in the pressure systems.
Findings
- The investigation could not confirm a specific cause for the instrument failure, as the pressure systems functioned correctly during post-accident testing.
- The pilot's decision to attempt a landing despite the lack of airspeed information was a critical factor.
- Pilot panic and inexperience during the emergency led to an unstable approach characterized by excessive speed and altitude.
- The sequence of porpoising and the subsequent nose gear collapse were direct results of the uncontrolled landing parameters.