What happened
On 20 August 1999, a Piper PA 28R-180, registration ZS-MLA, was conducting a cross-country training mission. The flight originated from Rustenburg and was intended to visit Potchefstroom and Lichtenburg before returning to Rand Airport. During the flight, the crew performed touch-and-go landings at the intermediate airfields.
As the aircraft approached Rand Airport on the downwind leg, the student pilot attempted to extend the landing gear. While the two main gear lights indicated successful deployment, the nose gear light failed to illuminate, and the gear-in-transit indicator remained active. Air traffic control confirmed via a low-level fly-past that the nose gear remained in the retracted position while the main gear was extended.
The crew proceeded to the Johannesburg general flying area to attempt an emergency gear extension. Despite activating the emergency system and performing positive G maneuvers to encourage the nose gear to free-fall, the nose gear remained stuck. The decision was made to return to Rand Airport for a landing on the grass area adjacent to Runway 29. The pilot managed to hold the nose off the ground for as long as possible during the landing. The aircraft traveled approximately 150 metres before coming to a stop. No injuries were reported for the two occupants.
The investigation
The investigation focused on why the nose gear failed to extend despite the use of emergency procedures. Investigators examined the mechanical state of the nose gear assembly and the surrounding components.
Findings
- A previous sheet metal repair performed on the exhaust muffler assembly had left insufficient clearance between the muffler and the nose wheel steering pivot bolt.
- The movement of the gear during taxiing, landing, and extension/retraction cycles caused the bolt to chafe against the sheet metal plate.
- This continuous friction caused the muffler assembly to shift, which ultimately exceeded the required clearance for the nose gear drag link assembly.