1983 British Airways Sikorsky S-61 crash

1983 British Airways Sikorsky S-61 crash

Accident summary
Date	16 July 1983
Type	Pilot error in poor visibility
Site	In the sea near St Mary's aerodrome, Isles of Scilly 49°55.4′N 6°14.9′W / 49.9233°N 6.2483°W / 49.9233; -6.2483Coordinates: 49°55.4′N 6°14.9′W / 49.9233°N 6.2483°W / 49.9233; -6.2483
Passengers	23
Crew	3
Fatalities	20
Survivors	6
Aircraft type	Sikorsky S-61N
Operator	British Airways Helicopters
Tail number	G-BEON
Flight origin	Penzance Heliport
Destination	St Mary's, Isles of Scilly

On 16 July 1983, British Airways Helicopters' commercial Sikorsky S-61 helicopter Oscar November (G-BEON) crashed in the southern Celtic Sea, in the Atlantic Ocean, when en route from Penzance to the St Mary's, Isles of Scilly in thick fog. Only six of the 26 on board survived. It sparked a review of helicopter safety and was the worst civilian helicopter disaster in the UK until 1986, when Boeing 234LR Chinook helicopter G-BWFC crashed in the North Sea.

Background

Owned by British Airways Helicopters, the Sikorsky S-61N registered G-BEON operated between Aberdeen and the oil platforms of the North Sea.

On 22 June 1983, Oscar November received its last annual certificate of airworthiness.

On 24 June 1983, it was being used as a replacement helicopter, operating the British Airways Helicopters service between Penzance and the Isles of Scilly. The helicopter which would normally run the service, ever since its purchase in 1974, was in for repairs.

Incident

Oscar November left Penzance on its scheduled 12:40 pm service to the Isles of Scilly. It was flying at 250 feet (80 m) over the Celtic Sea, due to poor visibility. Then, at 12:58 pm, air traffic control on St Mary's lost contact with the helicopter, before it had the chance to send a Mayday signal or to ditch under power. It had crashed nose-first into the sea and sunk immediately, only 2.5 miles (4.0 km) from St Mary's Airport. The six survivors were unable to don lifejackets in time, but were able to float for 30 minutes before St Mary's Lifeboat edit] Survivor's account

Langley-Williams told The Times (20 July 1983, p. 28 & 18 July 1983, p. 26): "It was very quick. I bumped forwards and hit my head on the seat in front." She asked Smith, "'What the hell is going on?'" The response was one word, by which time the passengers were chest-deep in seawater. "I closed my mouth and took a deep breath and by then I was under water." The seat had twisted on impact, tightening the seatbelt. "I realised I had not got an awful lot of breath left." She released the belt, opened the door and floated to the surface.

On the surface, she found the five other survivors. Shortly after, the two maroons signalling the launch of St Mary's Lifeboat could be heard. "We were just chatting about what would happen and I said the boat was on its way." Rescue helicopters from RNAS Culdrose could not see the survivors through the thick mist. "It was the most wonderful moment in my life to see the coxswain's face as he reached down over the side of the lifeboat."

The coxswain of the lifeboat was Matt Lethbridge.

Recovery

The fuselage of Oscar November was located by its locator beacon and was recovered from 200 ft (60 m) below the surface by the RMAS salvage vessel Seaforth Clansman at 1 p.m. on 19 July. The Seaforth Clansman, along with Penlee Lifeboat sponsons (wheel housing and floatation device). The starboard sponson was damaged but retained its capacity to float; the port was undamaged and failed to float. Three of the five main blades had been sheared off, along with the rear rotor blades. The cabin was badly damaged. The port-side escape windows were missing.

Investigation

The fuselage was taken to the Government's Air Accidents Investigation Branch at Farnborough, Hampshire.

Initially there was speculation that the helicopter could have flown into a flock of seagulls after mutilated bird corpses were found near the scene. However, Islanders found more dead seabirds on the shore, without mutilations. To add to the evidence against, the grille that prevents seabirds entering the engine was found intact.

Cause

A report investigating the incident was concluded twenty months later, in February 1985, finding the cause to be 'pilot error'. The official report concluded that the accident was caused by the pilot not observing and correcting an unintentional descent before the helicopter collided with the sea during an attempt to fly at 250 feet using visual clues in poor and deceptive visibility over a calm sea.^[1] The report also added that the following were contributory factors:^[1]

• inadequate flight instrument monitoring due to flying in visibility conditions unsuited to visual flight.

• lack of audio height warning equipment.

Safety recommendations

The Accident Investigation Branch made eight recommendations^[2] :

• The weather minima for helicopter flight in visual flight rules and the related crew instrument monitoring procedures should be removed.
• Radio Altimeters, with both audio and visual decision height warning, would be fitted to all helicopters operating offshore as a matter of urgency.
• Consideration should be given to the development of a ground proximity warning system for helicopters.
• The moving of the radio altimeter indicators to within the pilot's field of head-up vision should be examined.
• Helicopters used for public transport should be fitted with an automatically deployable survival radio beacon.
• Consideration should be given to pilots of helicopters used for public transport to wear lifejackets with dual frequency personal locator beacons.
• The use of QFE by the company on low level approaches to St Mary's aerodrome and the minimum RVR should be reviewed.
• The requirements concerning the strength of helicopter passenger and cabin attendant seats be reviewed.

Legacy

The main recommendation from the report was for an audible height warning on passenger helicopters operating off-shore and for the altimeter to be moved nearer to the pilot's 'head-up field of vision'. Ground proximity warning systems were made compulsory on passenger planes in 1977. It was also recommended that:

• The strength of both the passenger and attendant seats should be improved. All of the twin seats inside Oscar November sheared off, whilst the single seats remained fixed. The four surviving passengers were sitting in the single seats.
• A review of minimum weather standards for helicopter flight should take place. The pilot was flying within BA regulations which state that the pilot is allowed to fly on visual if visibility is 900 metres. The pilots' union, BALPA, had recommended this distance be increased to 1 nautical mile (1.9 km) after a Bell 212 crashed in the North Sea in 1981. If this had been accepted, the flight would have been conducted under IFR using instruments.
• Improvements should be made in barometric pressure indicators.
• Pilots should wear life-jackets with personal beacons.

The Sunday Times (24 March 1985) reported that of eight recommendations made in the report, seven were accepted by the CAA after the report, five had been suggested before the crash and three were already in force on other passenger aircraft operations at the time.

See also

• List of United Kingdom disasters by death toll
• Sumburgh disaster
• Air safety
• Accidents and incidents in aviation

References

1. ^ ^{a b} AAIB 1985, page 39
2. ^ AAIB 1985, page 40

• Seton, Craig (18 July 1983). "Reason for helicopter crash remains a mystery". The Times, pp. 1 & 26.
• Morris, Rupert (19 July 1983). "Concern mounts over factors in helicopter crash". The Times, pp. 1 & 28.
• Seton, Craig & Morris, Rupert (20 July 1983 . "17 bodies found as crashed helicopter is salvaged". The Times, pp. 1 & 28.
• Hamilton, Alan (22 July 1983). "The last flight of Oscar November". The Times, p. 8.
• "New safety measures for passenger helicopters...". (20 March 1985). The Times, p. 2.
• "Tight helicopter safety after Scillies crash". (21 March 1985). The Times, p. 2.
• Black, David (24 March 1985). "Safety aids suggested before Scillies crash". The Sunday Times, p. 4.

External links

• Accidents Investigation Branch – Accident Report 8/84
• Scilly History