Background
The commander of the PA-31, registration G-BWHF, had retired from flying Commercial Air Transport operations in August 2011. He had recently renewed his single pilot Instrument Rating and Multi Engine Piston (Land) planes rating and intended to continue flying part-time. The aircraft was privately operated for business purposes; the commander had last flown it on 10 November 1998. Accordingly, he planned a re-familiarisation flight. He was accompanied by another pilot who was not a flight instructor but had recent experience flying the aircraft and was familiar with the aerodrome.
Flight Preparations
A webcam recorded the pilots towing the aircraft to the refuelling point, refuelling it, and carrying out pre‑flight preparations. No witnesses observed any briefings. The commander first started the right engine, which initially ran roughly and backfired before running smoothly. The left engine started normally. The second pilot took his place in the front right seat. The aircraft taxied to the holding point of Runway 22, and witnesses reported it running normally. A witness who lived adjacent to the airfield heard power and propeller checks being carried out three or four times instead of the usual once per engine.
Departure and Climb
The aircraft took off from Runway 22 at 1105 hrs. It climbed straight ahead through a small patch of thin stratus cloud, whose base the witness estimated at approximately 1,000 ft above aerodrome level (aal). The aircraft remained visible as it passed through the cloud and continued climbing. The witness noted that apart from the unusual number of run-up checks, the aircraft appeared and sounded normal.
Weather Conditions
A pilot of a Robinson R22 helicopter that departed Welshpool at 1015 hrs described weather to the south of the aerodrome as drizzle with patches of broken stratus at 600–700 ft aal. He was able to climb the helicopter between patches of stratus until, at 1,500 ft, he was above the cloud tops. Visibility below the cloud was approximately 5–6 km; above cloud, it exceeded 10 km. He noted that the top of Long Mountain was in cloud. The R22 returned to the airfield and joined left-hand downwind for Runway 22. As it did so, its pilot heard a transmission from the pilot of the PA-31 stating that he was rejoining for circuits. The R22 pilot transmitted his position and then continued around the circuit, landing at about 1115 hrs.
Descent and Impact
After passing overhead Welshpool, the PA-31 made a descending left circuit and established on a left-hand downwind leg for Runway 22. A witness approximately 3.5 nm northeast of the accident site saw the aircraft coming towards him with both propellers turning. It made a left turn with engines apparently at a high power setting and, as it passed over Long Mountain, commenced a descent. The witness could not recall whether he still heard the engines as the aircraft descended, then lost sight of it behind the rising ground. A search was initiated when the aircraft failed to return to Welshpool. Its wreckage was located in an open field on the west slope of Long Mountain. No witnesses observed the actual impact with trees or the field surface, but a witness in the wood heard the engines audible immediately prior to impact. The accident, which was not survivable, occurred at 1117 hrs. Both pilots were fatally injured.