Status:	Final
Date:	25 MAY 1998
Time:	18:50 UTC
Type:	Aérospatiale / BAC Concorde 102
Operator:	British Airways
Registration:	G-BOAC
C/n / msn:	204
First flight:	1975
Engines:	4 Rolls Royce 593/610 Olympus
Crew:	Fatalities: 0 / Occupants: 11
Passengers:	Fatalities: 0 / Occupants: 53
Total:	Fatalities: 0 / Occupants: 64
Airplane damage:	Minor
Airplane fate:	Repaired
Location:	111 km (69.4 mls) N of Isles of Scilly, U.K. (Atlantic Ocean)
Phase:	En route (ENR)
Nature:	International Scheduled Passenger
Departure airport:	London-Heathrow Airport (LHR/EGLL), United Kingdom
Destination airport:	?

Narrative:
While climbing through FL410 a slight rumble was experienced, which turned out to be the separation of a section of the left hand middle elevon (5 feet x 3 feet). The captain decided to return to Heathrow.

CONCLUSIONS:
1. The reason for failure of elevon 3L S/No 1006R could not be established, but circumstantially it may have originated in the repaired trailing edge area.
2. The most likely failure scenario probably involved the growth of a relatively small disbonded area to a critical size and subsequent instantaneous failure.
3. The growth of the suspected disbond was not detected by NDE, despite an inspection programme well in excess of mandatory requirements.
4. The NDE techniques applicable at the time neither required nor were capable of examining metal-metal bond lines for flaws. As such approximately 50% of the repair accomplished at the trailing edge was not inspectable.
5. Despite the almost complete loss of integrity of the surface, the effects on controllability of the aircraft were negligible. This corroborates the results of a theoretical and experimental study conducted by the manufacturers which was presented to the investigation team and also came to this conclusion.

Sources:
» AAIB Bulletin 12/2000