Synopsis
The AAIB Bulletin reported an accident involving a Piper PA-38-112 Tomahawk, registration G-TOMS, on 26 November 2010 at 1125 UTC in the Brecon Beacons, Wales. The aircraft sustained severe damage to the airframe and engine. The pilot, the sole occupant, was uninjured.
History of the Flight
The aircraft departed Swansea at 1045 hrs on a private flight to Sleap for a 50-hour service. The pilot obtained weather data from the Met Office website prior to departure. The forecast for weather below 10,000 ft, valid from 0800 to 1700, predicted 20 to 40 km visibility in some areas, with isolated areas of snow and hail of varying intensity up to severe across Wales. The pilot reported clear conditions at departure. He took a course north from Swansea and reported VMC past Ammanford before encountering snow. There was occasional borderline VMC in the snow. The pilot, who did not have an instrument rating, decided to continue to Sleap.
At some point, he turned east to try to outrun the snow at 4,000 ft, but became disorientated and decided to head back to the coast around Swansea, setting a course of 215°. He descended to 3,000 ft to establish position, expecting to maintain 200 to 300 ft clearance from terrain, but the ground appeared to come up from beneath him. He applied throttle to regain altitude but there was no response from the engine. The pilot had not experienced engine problems until that point.
Accident Sequence
The aircraft approached the ground steeper than normal for a landing and tipped over onto its nose on contact, coming to rest inverted. The pilot, wearing a full harness, exited the aircraft through the cabin side window.
Pilot's Report
The pilot reported that snow from the west was much more widespread and severe than forecast. He considered the loss of engine response was either due to carburettor icing or a blocked air intake. Carburettor heating had been applied diligently and that heating may have exacerbated carburettor icing just prior to impact. The pilot also reported that snow flakes might have blocked the carburettor air intake. As a lesson learned, he stated he would approach conditions of deteriorating visibility more cautiously in the future and make an earlier decision to seek less marginal weather conditions.
Damage
The aircraft sustained severe damage to the airframe and engine.