Unexplained tow rope detachment leads to glider crash in Wales

Casualties unknown • Troed yr Harn, Talgarth, Powys, GB

A training flight in a Schleicher AS-K 13 ended in a forced landing near Talgarth after the tow rope unexpectedly detached during takeoff.

What happened

On 12 August 2022, a Schleiler AS-K 13 glider, registration G-DCMK, was performing an instructional aerotow flight from Talgarth airfield. The flight, involving an instructor and a student, was intended to progress the student toward solo flight capability. During the takeoff roll, which was lengthened by high temperatures and a crosswind, the glider became airborne ahead of the towing aircraft.

Shortly after liftoff, the student reported that the tow rope had detached from the glider. The instructor observed the rope trailing behind the towing aircraft. While the student maintained they had not pulled the release mechanism, the instructor took control of the aircraft to manage the emergency. Due to the low altitude and proximity to trees, the instructor had very limited options for a landing site. While attempting to maneuver toward a field, the crew encountered electricity cables before the aircraft struck the ground. The impact resulted in two serious injuries to the crew members.

The investigation

The AAIB examined the aircraft and the tow rope, finding no defects in the rope or the rings. The investigation focused on the nose tow release mechanism, a Tost E72 component. It was discovered that the over-centre adjustment screw had been removed from the release housing. This removal was reportedly done by club members to allow the E72 model to fit into the aircraft, as the screw on this specific model prevented proper installation.

The investigators also looked into whether movement in the cockpit could have triggered the release. While a cockpit cable guide had detached from the fuselage, the AAIB found that movement of the instrument panel would likely have increased friction on the release cable rather than causing an accidental release. The investigation could not definitively prove if the detachment was caused by an unidentified mechanical failure or an accidental input by the crew.

Findings

  • The unexplained detachment of the tow rope from the glider during the initial climb.
  • The removal of the factory-set adjustment screw from the tow release mechanism, which is a safety-critical component that should only be modified by qualified personnel.
  • The limited availability of suitable landing sites due to the hilly terrain surrounding Talgarth airfield.

Probable cause

The investigation was unable to conclusively determine the cause of the tow rope detachment, though possibilities included an unidentified mechanical failure of the release system or an inadvertent manual release by the crew.

Frequently asked questions

What happened in the 2022-08-12 Schleicher AS-K 13 accident near Troed yr Harn, Talgarth, Powys, GB?

A training flight in a Schleicher AS-K 13 ended in a forced landing near Talgarth after the tow rope unexpectedly detached during takeoff.

What aircraft was involved and where did it happen?

The accident on 2022-08-12 involved a Schleicher AS-K 13, registration G-DCMK , at Troed yr Harn, Talgarth, Powys, GB.

What was the probable cause of the accident?

The investigation was unable to conclusively determine the cause of the tow rope detachment, though possibilities included an unidentified mechanical failure of the release system or an inadvertent manual release by the crew.

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