What happened
On 15 October 2004, a private flight involving a Fournier RF3 motorglider, registration D-KMDP, experienced a mechanical failure shortly after departing Galway Airport. After reaching an altitude of approximately 500 feet, the pilot attempted to retract the undercarriage. While the gear released, it failed to lock in the upward position. The pilot climbed to 1,000 feet and attempted various maneuvers, including pulling positive and negative g-loads, to force the gear into position, but the mechanism remained stuck.
With the undercarriage jammed in a partially retracted state—leaving roughly 3 inches of the tire visible—the pilot requested a fly-past so air traffic control could visually assess the situation. Following this, the pilot decided to land with the gear in its fixed position. The pilot shut down the engine at a safe gliding distance and performed a landing on Runway 2/4 at 70 kph. The aircraft touched down 100 meters from the threshold and traveled an additional 30 meters before coming to a stop at a 20-degree angle to the runway centerline. There were no injuries to the pilot and no fire was reported.
The investigation
The investigation focused on the mechanical state of the undercarriage and the history of recent maintenance. Examination of the D-KMDP revealed that the guide wire on the starboard side of the wheel had snapped at the point where the wire was welded to a fixing washer. Evidence of corrosion was found at this weld. This broken wire had moved into a position where it interfered with the undercarriage door during the retraction attempt.
Investigators also noted that the aircraft's tire had been replaced three months prior to the incident, and the aircraft had not been flown since that maintenance. During taxiing prior to the accident, the pilot had experienced significant vertical oscillations when applying the brakes, which only ceased upon releasing the brake. It was determined that these oscillations likely caused the weakened guide wire to fracture.
Findings
- The primary cause of the undercarriage failure was the fracture of the starboard guide wire at a corroded weld.
- The broken wire moved into the path of the undercarriage door, preventing the gear from both locking in the up position and fully extending for landing.
- The mechanical stress from vertical oscillations during recent taxiing likely contributed to the wire's failure.
- The use of forks under the propeller by rescue services to lift the aircraft was noted as an unapproved method of recovery.