What happened
On 19 January 2002, a PIPER PA-24, registered ZS-CKK, was conducting a private flight from Cradock Aerodrome to Queenstown Aerodrome. The flight proceeded without incident until the aircraft began its approach to Queenstown. During this phase of flight, the aircraft suffered a complete failure of its electrical system.
In response to the failure, the pilot attempted to deploy the landing gear using the emergency extension mechanism. However, the gear failed to reach the fully down and locked position. Because the electrical failure had also rendered the green landing gear indication light inoperable, the pilot was unable to verify the status of the undercarriage. Upon touchdown on Runway 30, the landing gear collapsed. No injuries were reported for the two occupants on board.
The investigation
SACAA AIID investigators examined the mechanical and electrical components of the aircraft to determine why the system failed and why the emergency deployment was unsuccessful. The investigation focused on the electrical distribution network and the physical state of the landing gear assembly upon impact.
Findings
- The primary cause of the electrical failure was a broken generator feed bolt, which prevented the transfer of power from the generator to the aircraft's electrical system.
- The emergency extension of the undercarriage failed to secure the gear in the down and locked position.
- The loss of electrical power resulted in the loss of the landing gear down and lock indication light, preventing the pilot from confirming the gear's configuration prior to landing.