ASN Wikibase Occurrence # 157620
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| Date: | Thursday 19 January 1995 |
| Time: | c 12:40 |
| Type: |  Aérospatiale AS 332L Super Puma |
| Owner/operator: | Bristow Helicopters (BHL) |
| Registration: | G-TIGK |
| MSN: | 2044 |
| Year of manufacture: | 1982 |
| Total airframe hrs: | 13665 hours |
| Fatalities: | Fatalities: 0 / Occupants: 18 |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | 6 mi SW of Brae Alpha Offshore Installation, North Sea -
 United Kingdom
|
| Phase: | Approach |
| Nature: | Offshore |
| Departure airport: | Aberdeen Airport (ABZ/EGPD) |
| Brae Alpha Offshore Installation, North Sea | |
| Investigating agency: | AAIB |
| Confidence Rating: |  Accident investigation report completed and information captured |
Struck by lightning while descending to the Brae A platform in the North Sea. Part of a tail rotor blade was lost. The resulting heavy vibrations resulted in a fatigue failure of the Tail Gear Box mounting. This resulted in loss of tail rotor drive. The TGB however remained held in place by its hydraulic pipes, avoiding a shift in CG and a catastrophic pitch down.
The helicopter successfully ditched in 6-7 m waves (SS6+), all POB (2 crew and 16 passengers) evacuated to a raft and were rescued by vessel after c 60 mins. The helicopter sank at c 18:03 after a failed salvage attempt.
Causes
1 . One of the carbon composite tail rotor blades suffered a lightning strike which exceeded its lightning protection provisions, causing significant damage and mass loss.
2 . The dynamic response of the gearbox/pylon boom assembly to the tail rotor system imbalance induced rapid cyclic overstressing of the gearbox attachments which was accelerated by the early failure of the upper mounting bolt locking
wire, allowing consequent loosening and fatigue failure of this bolt.
3. Complete loss of the yaw control system and a momentary pitch-down as a result of detachment of the tail rotor, gearbox and pitch servo assembly.
4. The lightning strike protection provisions on this design of carbon composite tail rotor blade were inadequate due to it having been developed from an earlier fibreglass blade which had been certificated to lightning test criteria which have since become obsolete.
Accident investigation:
 |
|
Sources:
http://www.aaib.gov.uk/publications/formal_reports/2_1997__g_tigk.cfm
Location
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 16-Jul-2013 14:46 | TB | Added |
| 16-Jul-2013 14:49 | TB | Updated [Source] |
| 22-Aug-2014 10:18 | Aerossurance | Updated [Source, Narrative] |
| 10-Oct-2015 21:16 | Dr. John Smith | Updated [Location, Destination airport, Source, Embed code, Narrative] |
| 08-Mar-2017 16:43 | TB | Updated [Location, Destination airport, Source] |
| 19-Jan-2022 06:50 | Aerossurance | Updated [Location, Departure airport, Destination airport] |
| 25-Jan-2024 17:52 | harro | Updated [Other fatalities, Narrative, Accident report] |
| 30-Jan-2024 17:03 | Aerossurance | Updated [Time, Narrative, Category] |
Corrections or additions? ... Edit this accident description
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