What happened
On the night of 21 June 2002, a PIPER PA 28R-180, registration ZS-FOJ, was conducting a night VFR training flight from Wonderboom Aerodrome to Nylst/stroom Aerodrome. The flight was operated by a student pilot accompanied by an instructor. Approximately 15 nautical miles from the destination, the aircraft suffered a complete loss of electrical power.
In an effort to maintain communication, the pilot attempted to transmit blind on multiple frequencies. As the aircraft approached Nylstroom Aerodrome, the pilot attempted to deploy the landing gear using the manual extension system. This involved maneuvering the aircraft through various pitch, roll, and yaw inputs to increase G-loading to assist the extension. While the crew believed the gear had successfully deployed due to an increase in drag, the starboard main landing gear collapsed upon touchdown on Runway 10. Neither of the two occupants sustained injuries.
The investigation
SACAA AIID investigators examined the aircraft's electrical system and maintenance records. The investigation confirmed that the aircraft had been maintained according to regulations, with the most recent periodic inspection completed shortly before the incident. The pilot held a valid commercial license and the flight school held a valid accreditation.
Technical analysis focused on the cause of the electrical blackout. Investigators determined that a field wire connecting the alternator to the voltage regulator had failed. This specific failure prevented the alternator from charging the system, leading to the eventual discharge of the aircraft battery and the subsequent total electrical failure.
Findings
- The primary cause of the electrical failure was the failure of the field wire between the alternator and the voltage regulator.
- The loss of alternator function caused the battery to deplete, resulting in a total loss of electrical power.
- Although the manual emergency gear extension was utilized, the right-hand main landing gear failed to remain locked, leading to the collapse during landing.