Incident Boeing 747-436 G-BNLJ, Tuesday 30 October 1990
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Date:Tuesday 30 October 1990
Time:01:21
Type:Silhouette image of generic B744 model; specific model in this crash may look slightly different    
Boeing 747-436
Owner/operator:British Airways
Registration: G-BNLJ
MSN: 24052/789
Year of manufacture:1990
Fatalities:Fatalities: 0 / Occupants: 400
Other fatalities:0
Aircraft damage: Minor, repaired
Location:Bangkok-Don Mueang International Airport (DMK/VTBD) -   Thailand
Phase: Standing
Nature:Passenger - Scheduled
Departure airport:
Destination airport:Bangkok-Don Mueang International Airport (DMK/VTBD)
Investigating agency: AAIB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
On arrival at Bangkok a ground engineer advised the crew that a portion of one of the leading edge
Krueger flaps was missing. This was the No. 1 section of flap, inboard of the No. 2 engine, and the
section missing measured approximately 2 ft x 1 ft. The flight crew had not noticed any abnormalities
and not heard or felt anything unusual during flap retraction or extension on that sector.

The damage on the remaining portion of the flap, which is of composite construction, indicated that the final failure had occurred during a flap retraction and as a result of physical interference in mid-travel with the No. 2 engine pylon. There was no evidence of previous ground damage and the operator had not replaced or reworked this flap since the aircraft's delivery. According to the manufacturer, a number of operators had previously reported similar problems and these problems have been attributed to improper trimming of the flap during assembly or subsequent replacement. As well as investigating the quality control during manufacture, the manufacturer draws attention to a 1989 revision to the Maintenance Manual dealing with the trimming of the No. 1 and No. 16 sections of Krueger flap during replacement.

Accident investigation:
cover
  
Investigating agency: AAIB
Report number: 
Status: Investigation completed
Duration:
Download report: Final report

Sources:

https://assets.publishing.service.gov.uk/media/5422f96aed915d1374000749/Boeing_747-436__G-BNLJ_02-91.pdf

https://www.jetphotos.com/photo/6910082 (Photo)

Revision history:

Date/timeContributorUpdates
15-Apr-2025 16:51 Justanormalperson Added
15-Apr-2025 16:52 ASN Updated [Accident report, ]

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