What happened
On 04 January 2020, a Cessna 172RG, registration 8Q-GAD, was performing a training flight at Gan International Airport when the crew encountered a landing gear malfunction. During the approach, the instructor pilot noted that the green indicator light failed to illuminate after selecting the landing gear lever to the down position.
In an attempt to verify the gear's status, the crew performed several low fly-passes. While Air Traffic Control observed that all three landing gears appeared to be down, the locked condition could not be confirmed. Following these attempts, the crew proceeded to land using all available precautions. Upon touchdown, the nose landing gear collapsed, causing the aircraft to come to a halt after the propeller struck the runway. There were no injuries to the two crew members on board.
The investigation
The AICC investigation focused on the mechanical state of the landing gear and the maintenance history of the aircraft. While ground functional checks performed after the incident showed the gear operating normally, the investigation turned to the nose landing gear actuator assembly. The component was sent to Textron Aviation for specialized analysis.
Investigators also reviewed maintenance records, which revealed that the nose gear actuator had been sourced from a salvage provider with a note that its airworthiness status was to be determined by the installer. Furthermore, the investigation identified an unapproved modification in the cockpit: a red 'gear unsafe' indicator light had been installed without the necessary approval from the Maldives Civil Aviation Authority.
Findings
- The nose landing gear actuator assembly was not airworthy at the time of installation.
- Analysis by Textron Aviation confirmed the actuator rod seal leaked intermittently under specific hydraulic pressures and side loading.
- Significant wear and scoring were found on the bearing end bore and the piston rod, with dimensions exceeding allowable limits.
- An unapproved modification was present on the aircraft regarding the cockpit warning lights.