What happened
On 21 March 2016, a private flight traveling from St Francis to Rand aerodrome encountered a critical mechanical failure during its approach. While the pilot was performing the before-landing checklist in the Beech Baron 58P, registration ZS-KZC, the cockpit alarm sounded as engine power was reduced on short finals. Although the landing gear indicators initially appeared normal, the pilot was alerted by the tower that the nose wheel was not fully extended.
In an attempt to rectify the situation, the pilot and a passenger performed several manual gear extension attempts, but the nose gear remained jammed. Faced with no other options, the pilot proceeded to land on runway 35. Upon touchdown, the main landing gear collapsed, causing the aircraft to skid approximately 80 meters. The aircraft sustained substantial damage to the propellers, underbelly, and landing gear doors, but the pilot and three passengers were able to disembark without injury.
The investigation
SACAA AIID investigators examined the wreckage and the aircraft's maintenance history to determine why the gear failed to extend. The inspection of the nose gear assembly revealed that the retracting forward link rod assembly had disconnected from its attachment point. Specifically, the investigators found that the bolt, washer, and nut that secure this assembly were missing the required split pin.
Findings
- The primary cause of the accident was landing gear failure.
- The nose gear could not extend because the rod assembly disconnected due to a missing split pin.
- The investigation determined that the nut likely worked its way out of the joint because it was not properly secured with a split pin, a condition that allowed the bolt to migrate out of the joint under the influence of in-flight vibrations.
- Poor maintenance was identified as a contributing factor, as the missing pin was likely either omitted or improperly installed during a previous maintenance interval.