What happened
On 12 May 2001, a Piper PA-25-235, registration G-ASLK, was operating as a glider tug from Nympsfield Airfield in Gloucestershire. During a training flight in clear weather, the aircraft released a glider at approximately 2,200 feet. Following the release, the pilot intended to fly a right-hand circuit to avoid glider activity on the nearby north ridge, eventually dropping the tow rope at the launch point.
As the tug aircraft reduced speed to 10 and began a turn, it encountered a KA13 glider performing a familiarisation flight in a right-hand orbit to the south of the airfield. The two aircraft were on a collision course with a high closing speed. Although both pilots initiated immediate evasive maneuvers, the metal ring at the end of the trailing 60-metre tow rope struck the KA13. The impact damaged the glider's port wing, shattered the cockpit canopy, and struck the starboard wing. There were no fatalities, though a passenger in the glider sustained minor cuts and scratches from the broken acrylic.
The investigation
The investigation examined the visibility and positioning of the aircraft involved. The pilot of the Piper PA-25-235 noted that while focusing on maintaining separation from gliders on the north ridge, the KA13 glider had not been spotted. It was determined that the long nose of the aircraft may have obscured the glider's position. Additionally, a white paper placard placed on a black instrument component was found to be reflecting light onto the windscreen, contributing to a blind spot in the pilot's field of view.
Findings
- The collision occurred because the tow rope's end made contact with the KA13 glider.
- The pilot of the tug aircraft failed to identify the KA13 glider due to a combination of concentrating on other aircraft and obscured visibility.
- The aircraft's nose profile and a reflective paper placard on the instrument panel created a visual blind spot.
- The tow rope was being streamed at a speed of 120 MPH prior to the reduction in speed.