Synopsis
The helicopter, an Agusta Bell 206B Jet Ranger II registered G-SUEX, was on a public transport transit flight along the cliffs near Flamborough Head, Yorkshire. During the flight, a loss of power from its single Allison 250-C20B turboshaft engine probably led the pilot to attempt an autorotation to the cliff top. The manoeuvre was unsuccessful, and with rotor rpm declining, the helicopter struck the sea surface at the base of the cliffs. Both the pilot and the passenger sustained fatal injuries.
Background
G-SUEX (serial no. 8567) was manufactured in 1978 and was based in the south of England. It had operated a series of flights across Scotland over the preceding weekend and was scheduled to return to its home base at Manston on 15 September 2014, but weather delays postponed the departure. The aircraft was equipped with a single engine and had a commercial pilot with approximately 4,000 hours of flying experience.
History of the Flight
On 16 September 2014, the pilot and a friend departed from a temporary base at Bankhead Farm near Edinburgh, intending to fly to Humberside Airport for refuelling. The pilot occupied the front right seat and the passenger the front left. Routing initially overland, the helicopter reached the east coast about 20 nm north of Newcastle upon Tyne and then proceeded south along the coast. Radar data and eyewitness accounts indicate the helicopter varied between flying over land and sea, sometimes at less than 100 ft above sea level.
At approximately 1130 hrs, the helicopter landed in a field near Boggle Hole car park, Robin Hood’s Bay, due to thick fog with visibility about 50 m. The landowner offered accommodation or a lift, but the pilot declined. The pilot contacted Durham Tees Valley ATC by radio and later phoned Humberside Airport to check weather and confirm continuation of his transponder code. During the phone call, the pilot estimated a ground delay of up to one hour. The Humberside ATCO reported cloudbase broken at 700 ft and overcast at 1,100 ft, with improving conditions expected. The pilot also called a company staff member, stating he had tried to route around bad weather offshore but encountered further bad weather and returned inland. He mentioned he was scheduled for an Operator’s Proficiency Check that afternoon and planned to route to Biggin Hill via Humberside.
No further messages were sent to ATC or the company before departure. A witness near Hunmanby Gap, about 17.5 nm south of Robin Hood’s Bay, observed the helicopter flying no more than 60 ft above the foreshore in heavy sea fog with visibility between 800 m and 1.2 km.
Eyewitnesses on or near Flamborough Head Golf Course reported visibility of about 5 km and clearly saw the helicopter operating offshore, level with or just above the approximately 200 ft high cliff. One set of witnesses saw the helicopter turn slightly left away from the cliff, then abruptly right back towards it, before descending steeply out of sight below the cliff top. They realized a crash had occurred and contacted emergency services. An RAF SAR helicopter on a training flight nearby arrived within minutes.
Weather
The UK Met Office provided an aftercast. The Metform F215 forecast for area A1, valid from 0800 to 1700 hrs, predicted generally 20 km visibility with areas of haze reducing to 7 km, isolated mist until 1000 hrs (3 km), isolated fog (200 m visibility) clearing over land by 0900 hrs but persisting over sea and coastline, and isolated hill fog. Cloud was forecast as isolated to broken cumulus or stratocumulus with bases 1,500–3,500 ft and tops 4,000–6,000 ft, with isolated stratus bases 300–900 ft and tops 1,500 ft, and cloudbase at surface in fog.
At departure from Bankhead Farm, Edinburgh Airport reported light winds, visibility above 10 km, and 1–2 oktas cloud at 800 ft with scattered cloud at 2,100 ft.
The SAR Sea King commander from RAF Leconfield, operating 7 nm south of the accident site, reported cloudbase 700–800 ft amsl with a “goldfish bowl” haze below cloud. As they descended to the accident site, visibility improved to about 9 km at 200 ft amsl, with wind from 080° at less than 5 kt.
Recorded Data
Two GNSS receivers were recovered but contained no track data for the accident flight. Radar data from Edinburgh, Newcastle, Durham Tees Valley, and NATS en-route systems provided partial track information. Significant portions of the flight were below radar coverage due to low altitude.
Initial radar contact from Edinburgh PSR and NATS Lowther Hill SSR (0938–0959 hrs) showed the helicopter at 800–1,300 ft amsl, groundspeed 100 kt. Newcastle radar detected G-SUEX between 1021 and 1051 hrs; altitude descended to between 130 ft and 30 ft amsl with groundspeed 100 ±10 kt. Durham Tees Valley radar (1100–1115 hrs) showed altitude varying from 200 ft to 1,600 ft amsl, with a period of no contact when the pilot descended to low level to look at something.
Final radar contacts from Claxby SSR at 1238:17 and 1238:25 hrs placed the helicopter within 800 m of the accident site, at 200 ft amsl (Mode C corrected) and groundspeed approximately 90 kt (estimated from two points).
A witness audio recording from a camera inadvertently activated revealed no loud bangs; frequency analysis showed decay of main and tail rotor rpm.
Manufacturer’s Flight Mechanics Analysis
Details of the helicopter’s flight path, estimated weight, and configuration were provided by the manufacturer to support the investigation. The analysis informed the understanding of the aircraft’s performance during the final manoeuvres.