What happened
On 30 September 2006, a Piper PA 34, registration ZS-MNJ, was conducting a private VFR flight from Rand Aerodrome to Lanseria Aerodrome. Shortly after departure, the pilot attempted to retract the undercarriage, but the right-hand main gear failed to retract. In an effort to rectify the issue, the pilot cycled the gear using both the normal and emergency extension systems. However, the cockpit indication light continued to signal that the right-hand main gear was not properly locked in the down position.
After notifying Rand Aerodrome Air Traffic Control of the emergency, the pilot proceeded to Lanseria Aerodrome to perform a landing despite the unsafe gear configuration. Upon touchdown on Runway 06L, the right-hand main gear collapsed, causing the aircraft to veer off the paved surface and onto the grass. There were no injuries to the pilot or the three passengers on board, though the aircraft sustained minor damage to the wing's bottom skin and the landing gear.
The investigation
SACAA AIID investigators examined the wreckage and the aircraft's maintenance history during the recovery process. The investigation focused on the mechanical state of the undercarriage components and the effectiveness of previous inspections. The aircraft was placed on jacks to allow for a detailed examination of the landing gear assembly.
Findings
- The primary cause of the incident was the collapse of the right-hand main landing gear.
- A critical contributing factor was the failure of the right-hand main gear downlock link assembly.
- The link assembly bearing had worn beyond safe limits, which prevented the gear from retracting and extending correctly.
- While the part was subject to "on condition" maintenance—requiring only visual inspections—the extent of the wear was not detected during the most recent maintenance check at 4096.1 hours.