What happened
On 27 March 2019, a GP-14-SE VELO glider, registration OM-M821, was involved in an accident during an aerotow takeoff at Gowran Grange Airfield, Co. Kildare. While being towed by a Piper PA-18 150 Super Cub, the glider briefly became airborne due to bumps on the uneven runway surface before settling back down. As the aircraft eventually achieved full flight, it failed to clear the airfield boundary trees. The glider struck the trees, causing the towing cable to release, and subsequently descended into an adjacent field. The aircraft impacted through two sets of electric and wooden post-and-wire fencing, resulting in substantial damage to the airframe. The pilot, the sole occupant, escaped without injury.
The investigation
The AAIU examined the aircraft's wreckage and the assembly process used prior to the flight. Investigators discovered a double failure in the elevator control linkage located beneath the cockpit floor. Specifically, a control rod had fractured at the attachment point to the carbon fiber torque tube, and the attachment horn itself had failed at its root.
Crucially, the investigation focused on the position of the elevator at the time of the crash. While a correctly installed elevator would naturally rest in a slightly upward position if the linkage were severed, the elevator on OM-M821 was found in a downward-deflected position. This indicated that the horizontal tailplane had been incorrectly installed during the pre-flight assembly.
Findings
- The primary cause of the accident was the incorrect installation of the elevator during the glider's assembly.
- The design of the elevator hook mechanism allowed the lever to be improperly seated without being visually obvious to the pilot.
- During pre-flight ground checks, the pilot and an observer likely believed the controls were functional because the system still allowed for approximately 80% of the expected control stick travel, even though upward deflection was impossible.
- The pilot had limited experience with this specific aircraft type, which may have contributed to the oversight during the assembly and verification process.
Safety action
Following the investigation, the glider manufacturer implemented a redesign of the elevator hook mechanism to ensure that incorrect installation is no longer possible. The manufacturer also recalled and replaced the original mechanism on all other gliders of this type to mitigate the risk of similar occurrences.