What happened
On 24 September 2022, a Schleiker ASW 20 L, registration G-CFRW, was involved in a fatal accident near Pulborough, West Sussex. The aircraft was performing a private aerotow flight from Parham Airfield. During the takeoff sequence, witnesses observed that the glider appeared more nose-down than usual and the tug aircraft actually left the ground before the glider. After becoming airborne, the glider bounced twice on the surface and maintained an abnormal low towing position.
As the tug aircraft began a left-hand noise abatement turn, the glider released its tow cable at approximately 300 ft agl. Following the release, the aircraft pitched down at a steep angle and struck the ground in a high-speed, nose-low attitude. The impact was severe, causing the aircraft to disintegrate; the pilot was ejected from the cockpit and sustained fatal injuries.
The investigation
AAIB investigators examined the wreckage and the control mechanisms of the aircraft. While other flight controls were correctly attached, the investigation established that the elevator was not connected to the elevator control rod. The L’Hotellier cup connector, which joins the control pushrod to the elevator, was found disconnected. Notably, the spring clip required to secure the lock plate was absent from the connection.
The investigation also looked into the pre-flight procedures. The pilot had assisted in rigging another glider earlier that morning and had performed a Daily Inspection (DI) on a club aircraft. However, there was no evidence that a Positive Control Check—a procedure where control surfaces are physically restrained while the cockpit controls are moved—had been performed on G-CTRW. Investigators noted that a standard control check might not detect a disconnected elevator because the surface can still move via gravity.
Findings
- The aircraft likely became airborne with the elevator control disconnected.
- The elevator control connection was not correctly made during the rigging process.
- The absence of a spring clip on the L’Hotellier connector meant there was no secondary security for the connection.
- It is probable that a Positive Control Check was not conducted on the aircraft prior to flight, which could have identified the disconnection.
- The pilot may have been distracted or cognitively satisfied that checks were complete after performing them on a different aircraft.
Safety action
Following the accident, the British Gliding Association (BGA) has published a 'Safe Rigging Toolkit' focusing on human factors. Two Safety Recommendations were also issued: one to mandate and document Positive Control Checks during Daily Inspections, and another to clarify the limitations of using flaps for pitch control in the event of an elevator failure in the aircraft's Flight and Operations Manual.