Incident Overview
On 22 May 1998, a Piper PA-28-151, registration G-BCTA, was returning to Manston from Le Touquet. Normal full and free control checks were carried out during pre-departure. During the flight, the low voltage warning light illuminated. Despite reducing electrical loads and briefly selecting full power, the light did not extinguish. The ammeter remained normal, and no other electrical services appeared affected.
Control Restriction
The autopilot was used to maintain heading towards the Dover VOR. Just short of the VOR, the autopilot was disengaged and a descending turn was made to a northerly heading. Shortly after, the pilot found the control yoke movement restricted: no movement to the right from neutral, limited movement to the left remained. The autopilot was confirmed disengaged. The passenger, also a private pilot, checked his controls and confirmed the restriction. The pilot reported that even with considerable force, the yoke could not be moved right, while rudder and elevator control remained available.
Precautionary Landing
The pilot decided on a precautionary landing in the nearest suitable field. At about one mile from the field, houses and power lines were seen at the threshold, pushing the touchdown point further into the field. As the aircraft flew over the houses, the pilot realized the field had a considerable up-slope with a mature hedge on the far side. However, he was committed to landing, having already set the mixture control to idle cut-off before identifying the field's unsuitability. On the ground, the pilot managed to turn the aircraft about 45 degrees before it struck the hedge and bank, tearing the left wing from the fuselage.
Post-Accident Examination
The wrecked aircraft was examined by the maintenance company's Chief Engineer. He found no evidence in the flying control system to explain the restriction. AAIB requested the autopilot components for detailed examination. Functional testing at an overhaul agency revealed that the on-off switch was not always positive, tending to stick in both the 'on' and 'off' positions.
Injuries and Damage
The pilot sustained minor injuries; the passenger none. The aircraft sustained substantial damage.