What happened
On 10 November 2018, a Vulcanair P.68R, registration ZS-VRA, was conducting a Part 141 training flight at Progress Aerodrome, Port Elizabeth. The flight, consisting of an instructor and two student pilots, initially proceeded to Port Elizabeth International Airport for circuit training. During the second circuit, the crew observed an unsafe landing gear warning, with the nose and both main gears indicating a red, unlocked status.
After attempting to recycle the gear, the cockpit indicators still showed the nose and right-hand main gear as unlocked, while only the left-hand gear showed a green, locked status. The instructor opted to pull the hydraulic pump circuit breaker and returned to the base at Progress Aerodrome. Before landing, the instructor performed a low fly-past to have ground observers visually confirm the gear position. Upon receiving confirmation from the ground that the gear appeared down, the crew proceeded with a normal approach. However, upon touchdown on runway 2/25, the nose gear collapsed, causing the aircraft to skid on its nose section until it came to a halt. The incident resulted in no injuries, though the aircraft sustained minor damage to the nose gear doors and rod ends.
The investigation
The investigation focused on why the nose gear failed to remain locked despite visual confirmation from ground observers. Investigators examined the aircraft's maintenance history and found that a similar landing gear indication issue had occurred just two days prior, on 08 November 2018. While the maintenance organization (AMO) had addressed a sensor issue previously, the investigation noted that the recent maintenance did not follow best practices regarding duplicate inspections for critical components.
Post-accident testing of the hydraulic system revealed no leaks or mechanical malfunctions, and the landing gear operated normally during ground tests. The investigation could not determine the specific cause of the down-lock mechanism failure because the system functioned correctly during subsequent inspections.
Findings
- The primary cause of the collapse was that the nose gear was not locked in the extended position.
- The crew did not activate the emergency landing gear extension T-handle as mandated by the Pilot Operating Handbook (POH) when the unsafe indication was first identified.
- There was a documented history of unreliable landing gear position indications on this aircraft.
- Maintenance performed on the landing gear system prior to the incident lacked the required dual inspection to ensure correct fitment and troubleshooting.