Incident Overview
During the landing roll, the nose landing gear collapsed after it was lowered to the runway. The aircraft had accumulated 4 hours and 6 cycles since its last progressive inspection two days prior.
Examination Findings
An FAA maintenance inspector examined the nose landing gear assembly. The nose landing gear actuator was not damaged externally and was removed for further examination. Disassembly revealed an extra packing, similar to an O-ring, installed inside the actuator. This extra packing allowed the nose landing gear down-and-locked light to illuminate but caused the motor to shut off before the gear was fully extended.
Maintenance History
Review of the airplane logbooks indicated that a progressive inspection was signed off two days before the accident. During that inspection, a leak was noted at the nose landing gear actuator switch. The corrective action recorded was that the O-rings were replaced. According to the illustrated parts list for the nose landing gear actuator, two packings are specified for installation.
Mechanic Error
The director of maintenance reported that the mechanic responsible for replacing the packings was provided with two packings but only removed one from the actuator. This resulted in one old packing remaining in the actuator along with the new packing, creating the extra packing condition that prevented full extension.
Conclusion
The extra packing in the nose landing gear actuator caused the gear to not fully extend, leading to the collapse during the landing roll.