ASN Wikibase Occurrence # 18540
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| Date: | Thursday 6 November 1986 |
| Time: | 11:31 LT |
| Type: |  Boeing Vertol BV234LR Chinook (CH-47) |
| Owner/operator: | British International Helicopters |
| Registration: | G-BWFC |
| MSN: | MJ004 |
| Fatalities: | Fatalities: 45 / Occupants: 47 |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | North Sea, 2.5 mi E of Sumburgh -
 United Kingdom
|
| Phase: | Approach |
| Nature: | Offshore |
| Departure airport: | Brent Charlie Offshore Installation |
| Sumburgh, Shetland (LSI/EGPB) | |
| Investigating agency: | AAIB |
| Confidence Rating: |  Accident investigation report completed and information captured |
Crashed into the North Sea when the forward transmission spiral bevel ring gear failed. This caused the rotor synchronisation to be lost and the aft rotors cut through the aircraft as it broke up in mid air. The underlying causes were the inadequacy of a previously accepted test program and the failure of a stringent inspection programme.
Only two of the 47 POB (44 passengers and 3 crew) survived.
The helicopter was normally based at Aberdeen Airport but had been based at Sumburgh Airport since 3 November 1986 to operate a shuttle service from the Shell Brent field in the East Shetland Basin. On 6 November the first flight was delayed due to an oil leak from an engine gearbox that was soon rectified and the aircraft left Sumburgh at 08:58 with 40 passengers for the Brent Field. The aircraft visited three platforms with exchanges of freight and passengers then departed Brent Platform C at 10:22 with 44 passengers on board for return to Sumburgh Airport. It transited at a height of 2,500 feet, and as it approached Sumburgh it was cleared to descend to 1,000 feet. Reporting 4.5 miles from the airfield, the controller cleared it to land on helicopter runway 24. Nothing else was heard.
The crew noticed an increased noise level in the flightdeck followed by a bang. Despite applying full cyclic pitch control the aircraft did not respond and nose-dived towards the sea from a height of 150 feet (50 m). The helicopter hit the sea, broke up and sank. A Coastguard search and rescue helicopter which had just departed Sumburgh Airport reported liferafts in the sea. It then observed a survivor clinging to a substantial piece of wreckage. While they winched the man on board another survivor was noted amongst the floating bodies. With no signs of other survivors the Coastguard helicopter flew the survivors to Lerwick for transfer to hospital.
The AAIB made three safety recommendations:
1) Certification procedures be reviewed so that all modifications to vital components are adequately scrutinised and tested before approval and more closely monitored after their introduction into service.
2) The Civil Aviation Authority should report on the progress that has been made towards the early incorporation of a specification for suitable condition monitoring systems into airworthiness requirements for helicopters and indicate the time scale and scope of likely developments.
3) Requirements relating to the ADELT (Automatically Deployable Location Transmitter) equipment, including location, crashworthiness, protection and power supplied, be review.ed in the light of the accident. (The beacon did not operate due to impact damage to the aft part of the aircraft)
Accident investigation:
 |
|
Sources:
https://www.pprune.org/rotorheads/468256-shetland-chinook-legacy-remembered.html
https://www.gov.uk/aaib-reports/2-1988-boeing-vertol-bv-234-lr-g-bwfc-6-november-1986
https://airfactsjournal.com/2020/04/i-survived-the-deadliest-helicopter-crash-in-european-history
https://www.energyvoice.com/insights/122522/chinook-remembered-images-show-aftermath-1986-helicopter-crash/
Media:
#OTD 1986 Sumburgh BV234 accident, 45 fatalities https://t.co/NFzKyRI6mY#helicopter #accident #flightsafety #aviationsafety
— Aerossurance (@Aerossurance) November 6, 2022
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 17-May-2008 11:10 | ASN archive | Added |
| 02-Jan-2010 07:36 | TB | Updated [Time, Aircraft type, Other fatalities, Location, Phase, Nature, Departure airport, Destination airport, Source] |
| 05-Apr-2010 05:42 | TB | Updated [Aircraft type] |
| 15-Jan-2011 05:39 | Anon. | Updated [Narrative] |
| 07-Jun-2012 03:24 | TB | Updated [Time, Source, Narrative] |
| 24-Nov-2012 15:35 | Dr. John Smith | Updated [Source, Embed code, Narrative] |
| 23-Dec-2012 09:04 | TB | Updated [Time, Source, Embed code, Narrative] |
| 29-May-2013 13:43 | Dr. John Smith | Updated [Source, Embed code, Narrative] |
| 30-Oct-2014 02:23 | Dr. John Smith | Updated [Destination airport, Embed code] |
| 21-Jan-2016 20:47 | Aerossurance | Updated [Aircraft type, Location, Departure airport, Narrative] |
| 11-May-2016 05:51 | Anon. | Updated [Departure airport] |
| 17-Oct-2016 15:42 | Aerossurance | Updated [Time, Departure airport, Source, Narrative] |
| 17-Oct-2016 15:45 | Aerossurance | Updated [Source] |
| 17-Oct-2016 15:47 | Aerossurance | Updated [Source] |
| 17-Oct-2016 15:49 | Aerossurance | Updated [Source] |
| 01-Mar-2017 16:09 | TB | Updated [Location, Source] |
| 27-Apr-2020 15:16 | Aerossurance | Updated [Location, Source] |
| 06-Nov-2023 11:34 | Aerossurance | Updated [Source, Embed code, Narrative] |
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