History of the Flight
The gliding club at Aston Down normally used a winch for launches, but on the morning of 14 September 2001, the winch became unserviceable after four successful launches. To continue operations, the club arranged to borrow a Piper PA-25-235 Pawnee tug from a nearby club at Nympsfield. At approximately midday, an Aston Down club instructor, who was a qualified tug pilot, flew the aircraft from Nympsfield to Aston Down. The weather was fine with scattered cumulus at 3,000 feet, visibility over 10 km, and surface wind around 315°/15 kt.
During the afternoon, the instructor performed nine aerotows using the prescribed departure routes. After each launch, the tug varied its rejoining procedure, conducting both left and right circuits and landing diagonally across the grass south of Runway 03 threshold, likely to avoid noise-sensitive areas and to achieve a more controllable into-wind touchdown.
The Cirrus glider was the seventh aerotow. The first launch attempt was aborted after about six feet due to cross-wind wing instability, but a successful launch followed at 1510 hrs. The glider released from the tug at approximately 2,000 feet above ground level upwind west of the field. The tug then towed two more gliders.
Collision
Witnesses saw both aircraft as they returned to the airfield. The glider flew a right-hand circuit for an approach to land parallel to the runway centerline on the southern grass area. The tug joined on a left base leg, intending to cross the extended centerline, turn into wind, and land diagonally. The two aircraft converged at an estimated height between 150 and 400 feet. The glider was turning with slight right bank, while the tug was in a 20° banked continuous level left turn. Neither pilot was seen to take avoiding action. The aircraft collided and both descended out of control, fatally injuring both pilots upon impact with the ground.
Wreckage Examination
The wreckage of both aircraft lay in ploughed fields about half a kilometer south of the intended landing area, separated by approximately 160 meters, with the tug east of the glider.
Tug Aircraft (Piper PA-25)
The tug struck the ground almost vertically, suffering total disruption of the nose and forward fuselage. It had rotated about 90° before coming to rest on its left side, indicating a left spinning motion prior to impact. All wreckage remained within the ground impact area. The tow rope was found separately near the released tow hook; the hook likely opened due to impact forces.
Clear witness marks showed left and right wing leading edges at impact. The left wing impression was at approximately 90° to the right, consistent with the left wing folding upward against the fuselage before ground contact. Both primary lift struts on the left wing were bent upward from compression buckling, with heavy pre-impact damage and red paint transfer (smearing) overlay on white paint. Red paint was also found on lower surfaces of the inboard lift struts and on adjacent skin panels, plus a small area on the left cockpit roof.
The control system showed no pre-impact defects. Flaps were set to mid-position. The four-bladed wooden propeller fragmented on impact, but collision damage on the glider indicated the propeller was rotating under power at the time of collision.
Cirrus Glider
The glider struck the ground in a very steep nose-down attitude, slightly beyond vertical, causing complete disruption of the nose and cockpit. It came to rest inverted, having turned from initial impact marks, indicating left rotational momentum. Both wings remained attached, with clear leading-edge impressions. The left wing impression terminated at the fractured outboard end, confirming the outboard section separated before ground impact. The right wing was intact at impact but broke after.
Pre-impact damage was found at the tail: chordwise cuts characteristic of propeller strikes at the separation point of the left tailplane, and a lozenge-shaped area of green, blue, and red paint transfer on the lower left fuselage extending onto the fin and rudder, with smearing at about 12° to the fuselage axis. The rudder trailing edge appeared deflected about 13 cm to the right, but this is likely spurious due to forces during paint transfer.
No pre-impact defects were found in primary controls except for the left aileron fracture where the outer wing panel separated. Airbrakes appeared partially extended at impact. A separate debris area contained three segments of left tailplane (the entire missing section) and the outer 1.7 meters of the left wing, with smaller tip fragments scattered eastward.