History of the Flight
On 27 August 1999 at 1605 UTC, a Piper PA-28-161 (registration G-BUJP) was on a private flight. The pilot, aged 71 with 150 hours total flying experience (42 on type), departed from Welshpool Airfield and returned after a short flight. He descended to circuit height (1,500 feet agl) and reduced airspeed to 90 kt for downwind checks, including temporary use of carburettor heat. On base leg, he slowed to 80 kt and selected two stages of flap. The pilot normally selected carburettor heat before reducing throttle on base leg, but could not recall doing so on this occasion. After turning onto final approach, he set throttle to about 1,500 RPM. The aircraft descended normally until the pilot made radio contact with another aircraft ahead on approach, which intended a glide approach. Considering a possible go-around, the pilot advanced the throttle when about halfway down final approach after noticing the aircraft was slightly low. The engine did not respond. He checked the electric fuel pump and switched from right to left fuel tank. With no response, he switched back to the right tank; the engine briefly responded then lost all power.
The pilot selected a field for forced landing and transmitted a Mayday call. After descending over trees, he selected third stage flap and executed a touchdown in the field. During deceleration, braking was affected by rough ground in the 200-metre field. Steering toward a gap in the boundary, the aircraft encountered bushes and barbed wire, continued through, and the right wing struck a tree before stopping 20 metres into the next field. The pilot shut down the engine and was performing checks when the passenger, who had left the aircraft, reported fuel leaking from the right wing. The pilot removed the ignition key and exited immediately.
Inspection of the Aircraft on Site
The pilot later checked the fuel tanks. Each had been half full before the flight. The left tank remained about half full; the right tank (used earlier) had been damaged—the wing leading edge compressed by some 15 cm from the tree strike—and was still leaking fuel. The left fuel tank gauge had become faulty during the flight, changing from half to full indication. A senior engineer who inspected the aircraft on site could not recall the carburettor heat control setting, but stated the engine was run subsequently in the field.
Weather Information
The pilot reported weather at the time (calculated for 500 feet agl at Welshpool) as air temperature 17°C with dew point 10°C. Shawbury recorded 20°C and dew point 11°C. A standard carburettor icing chart indicated these conditions were well within the regime where moderate carburettor icing should be expected at cruise power and serious icing at descent power.
Previous Engine Problems
The pilot mentioned anecdotal reports of prior engine problems on G-BUJP, including one instance in the circuit followed by engine stoppage after landing on 23 August, which an engineer reportedly cured by adjusting the carburettor slow running control. Similar problems in the circuit occurred the day before this accident, with the engine cutting on the runway.