Flight to Clutton Hill Farm
The pilot flew a Piper PA-24-250, registration G-APUZ, from Blackbushe to Clutton Hill Farm, a private airstrip located approximately 7.5 nm east-southeast of Bristol Airport. The purpose was to allow two potential purchasers, also pilots, to view the aircraft. A successful landing was made on grass Runway 07, which measures 590 metres in length and 27 metres in width. The runway had a down slope at the touchdown threshold end. The surface wind at the time was reported as 080° at 17 knots.
After arrival, the aircraft and its documentation were examined by the prospective buyers. A demonstration flight was then conducted using Runway 07. During this flight, confusion arose regarding the landing gear position when the gear was selected down. The navigation lights had been switched on, which dimmed the green 'landing gear safe' indicator light, rendering it not visible. The pilot recognized and resolved the uncertainty.
Landing Difficulties
A landing attempt on Runway 07, which lacked identification, threshold, or touchdown markings, was initiated but resulted in a go-around. A second approach, with rain on the windshield, led to an "awkward touchdown" causing the aircraft to bounce. The pilot applied power and executed another go-around. The pilot was surprised by the extent of the bounce, as the aircraft did not appear to be sinking excessively at the time of ground contact. A third landing attempt was completed apparently normally, and the aircraft was taxied to the parking area.
Wing Damage Discovery
Before the return flight to Blackbushe, the pilot noted damage to the upper skin of the right wing, describing rippling of the skin. He discussed this with the other two pilots. He recalled a similar degree of damage to the left wing over a year earlier, when the skin had "rippled due to some movement in the riveted joints". On that previous occasion, engineers had re-riveted a number of lines of rivets. The pilot considered that the right wing damage had been caused by the bumpy runway and the "awkward ground contact".
Return Flight and Gear Problem
The pilot initially contemplated leaving the aircraft at Clutton Hill until an engineer could inspect it. However, he reasoned that since he had flown a normal go-around, circuit (with landing gear extended), and landing after the awkward contact, a return flight to Blackbushe could be undertaken. He elected to fly back with the landing gear extended as a precaution. After take-off, the pilot retracted the gear as a reflex action. One of the observing pilots at the strip noted that the landing gear did not fully retract. Subsequent attempts to lower the gear using both normal and emergency systems were unsuccessful as the pilot neared Blackbushe. In contact with Farnborough ATC, he informed them of the problem. A low approach and go-around at Farnborough Airport revealed that the landing gear was only partially extended. Farnborough ATC communicated with the aircraft owner's engineering contractor to advise of the issue. Several attempts to resolve the situation were made but failed. The pilot then diverted to Turweston Aerodrome, which was the engineering contractor's base.
Landing at Turweston
The engineer arranged for emergency services to be in attendance at Turweston by the time of the aircraft's arrival. The pilot carried out a successful landing with the landing gear partially retracted. There was no fire, and the pilot, who was uninjured, vacated the aircraft normally.
Engineering Findings
Subsequent engineering examination revealed displacement of the rear trunnion mounting frame of the right landing gear, allowing the leg to incline approximately 10 degrees aft of its normal position. This displacement resulted from general sheet-metal distortion in parts of the adjacent wing structure. The leg displacement caused fouling against the structure, which permitted partial retraction but prevented extension, regardless of the method attempted. It was noted that operation of any mechanical system attached to a distorted structure will generally result in failure of the mechanical system to function correctly due to incorrect geometry.
Aftermath
Six days after the accident, the pilot was informed that the aircraft had touched down on some "bad ground", approximately 50 feet short of the unmarked Runway 07 threshold at Clutton Hill Farm. Three short wheel tracks were found in the grass at that location. It was presumed that the structural damage had occurred at this point.