Accident Overview
On 30 May 2018, at approximately 1223 UTC, a Bell 206B3 Jet Ranger III helicopter, registration G-OPEN, crashed in a field near Aldborough, North Yorkshire. The pilot, who was the only person on board, suffered fatal injuries. The helicopter was destroyed by impact and post-crash fire.
History of the Flight
The pilot planned to fly G-OPEN from Husthwaite to Walton Wood Airfield for its annual maintenance check, a route he had flown many times. After an initial postponement due to weather, the pilot departed at 1216 hrs. The cloud base en route was forecast between 300 ft and 700 ft with visibility possibly reducing to 3,000 m. At 1218 hrs, the pilot contacted RAF Linton-on-Ouse ATC, requesting a Basic Service, reporting an altitude of 700 ft. Radar data showed the helicopter flew slightly left of the planned track and entered the Linton-on-Ouse MATZ.
Witness Observations
Witnesses near the accident site reported seeing the helicopter flying normally before it pitched up into a steep climb and entered cloud. The helicopter was heard in the cloud, described as very loud. It emerged from the mist, moved erratically, then rotated approximately 540°, corrected, and entered a steep nose-down descent. Just before impact, the helicopter appeared to level, but continued descending. The helicopter caught fire immediately upon ground contact. Some witnesses described unusual engine sounds.
Radar Data
Secondary surveillance radar recorded the flight until about 1 nm from the accident site. The helicopter had been flying at 520–720 ft amsl at about 97 kt. Approximately one minute before the last data point, it climbed from 520 ft to 1,020 ft amsl in 16 seconds (climb rate 1,500–2,250 ft/min), then descended and climbed again. Groundspeed during these maneuvers averaged about 60 kt.
Helicopter Information
G-OPEN was a 1994 Bell 206B3, powered by a Rolls-Royce Allison 250-C20J turboshaft engine. It had analogue flight instruments and a two-axis Bendix King KAP 150-H autopilot. The helicopter had accrued 4,038 flight hours. Its last scheduled maintenance was a six-months inspection on 13 March 2018, and the ARC was valid until 12 April 2019. The next annual inspection was due on 31 May 2018.
Wreckage Examination
The helicopter struck the ground in an approximately level attitude with a high vertical rate of descent and some forward speed. The tail, landing gear, and main rotor struck first. The helicopter became inverted and caught fire. Both main and tail rotors were rotating at impact. The landing gear separated, fuel cell ruptured, and post-impact fire consumed much of the fuselage. Detailed examination revealed no pre-existing defects. The engine was running at impact with no anomalies found. All fractures were consistent with overload.
Probable Cause
The investigation could not determine why the helicopter entered cloud but stated it is probable that the pilot was distracted or became disorientated in the poor weather conditions. Having entered cloud, it is likely that the pilot became spatially disorientated and was unable to maintain control of the helicopter.