What happened
On June 1, 2007, a Gulfstream G-V, registration HB-IMJ, operated by G5 Executive AG, was performing a commercial non-scheduled flight from Rotterdam to Zurich. During the approach to runway 14, the crew extended the landing gear but discovered that the nose gear had failed to extend and lock into position, despite the main gear being properly deployed.
Following a missed approach, the crew attempted to re-extend the gear. During this process, they noticed the hydraulic fluid level in the left system began to drop. A second approach was conducted, but the nose gear remained unserviceable. The crew even attempted emergency procedures, including using aircraft maneuvers to induce g-loads to force the gear down, with assistance from the manufacturer's technical hotline. Ultimately, the pilot declared an emergency. The aircraft touched down on its nose at 20:53 UTC, resulting in significant damage to the aircraft, though there were no injuries among the crew or the five passengers on board.
The investigation
Investigators examined the aircraft's flight data recorders and cockpit voice recordings to reconstruct the sequence of events. The technical focus centered on the nose landing gear door actuator. Physical examinations of the wreckage revealed that the four fastening screws on the shuttle valve end cap (gland) had failed, leading to the breakage of the end cap itself. Fractographic analysis of the hardware and the end cap confirmed that the failure was related to material fatigue and improper installation.
Findings
- The primary cause of the accident was the failure of the four bolts securing the shuttle valve end cap, which caused the cap to break.
- This breakage led to a hydraulic leak, which subsequently caused the failure of the emergency gear extension system.
- The investigation identified that the retaining screws were of an inappropriate type and had been insufficiently tightened.
- The material strength of the end cap flange was found to be inadequate for the operational stresses.