What happened
During a series of takeoff and landing exercises at Lanseria Aerodrome, a Mooney M20J, registration ZS-LBU, experienced a landing gear collapse upon touchdown on runway 06R. The pilot was performing the second circuit of the flight when, while on the downwind leg, the aircraft was instructed by Air Traffic Control to reduce speed due to departing traffic.
While the pilot believed the undercarriage had been extended and verified the switch position through both visual and tactile checks, the aircraft's gear remained retracted. Upon touchdown, the pilot noted a gentle contact with the centerline followed by sparks emitting from the nose wheel area due to surface irregularities. This was immediately followed by the collapse of the undercarriage. The impact caused the aircraft to scrape along the runway, leading to smoke and a burning smell in the cockpit. The pilot promptly shut down the fuel and electrical systems and evacuated the aircraft. Fire and rescue services attended the scene to assist with the recovery of the aircraft.
The investigation
An investigation by the SACAA AIID examined the mechanical state of the aircraft and the pilot's actions. Post-incident inspections by a CAA-approved maintenance organization found no mechanical or electrical malfunctions within the landing gear system. The investigation noted that the damage to the gear doors was consistent with the gear being in the "up" position at the moment of impact.
Investigators also examined the aircraft's warning systems. Although the pilot reported not hearing the gear-unsafe aural warning, the system was found to be serviceable. Furthermore, the investigation noted that the pilot could not confirm whether the gear-position indicator lights had been correctly illuminated during the approach, and he did not recall checking the specific visual gear-position indicator located on the floorboard.
Findings
- The aircraft sustained damage to the propeller, underbelly, and the undercarriage push-rod.
- The weather conditions at the time of the incident were clear with good visibility (CAVOK) and were not a contributing factor.
- There were no mechanical defects or malfunctions found in the landing gear mechanism or the warning systems.
- The primary cause of the incident was that the pilot forgot to lower the landing gear.