| Status: | Final |
| Date: | Thursday 27 December 1979 |
| Time: | 18:39 UTC |
| Type: |  Boeing 747-121SF |
| Operator: | Pan American World Airways (Pan Am) |
| Registration: | N771PA |
| MSN: | 19661/70 |
| First flight: | 1970-07-24 (9 years 5 months) |
| Total airframe hrs: | 34615 |
| Cycles: | 9505 |
| Engines: | 4 Pratt & Whitney JT9D-7D |
| Crew: | Fatalities: 0 / Occupants: 3 |
| Passengers: | Fatalities: 0 / Occupants: 0 |
| Total: | Fatalities: 0 / Occupants: 3 |
| Aircraft damage: | Substantial |
| Aircraft fate: | Repaired |
| Location: | London-Heathrow Airport (LHR) ( United Kingdom)
|
| Phase: | Landing (LDG) |
| Nature: | Cargo |
| Departure airport: | New York-John F. Kennedy International Airport, NY (JFK/KJFK), United States of America |
| London-Heathrow Airport (LHR/EGLL), United Kingdom |
The accident happened whilst the Boeing 747 cargo aircraft was being landed on runway 23 at London Heathrow Airport (LHR). At touchdown the number 4 pylon forward bulkhead, which supports the front of the engine, began to break free of the pylon because of weakening by fatigue and other pre-existing damage. The resulting downward movement of the engine during the landing roll ruptured the engine fuel feed pipe and several other connections with the engine including engine monitoring and fire warning circuitry. The high volume of fuel issuing from the ruptured fuel pipe caused a severe fire to develop under the number 4 pylon. The fire continued until the crew physically observed the fire as the aircraft was being turned off the runway at block 77(0), at which point the fire drill was carried out. This resulted in the closure of the fuel shut-off valve in the wing. The aircraft was brought to a halt and the airport fire service quickly brought the residual fire under control.
Probable Cause:
CAUSE: "The accident was caused by the failure of the forward bulkhead of the No 4 pylon when it was subjected to landing loads after it had been weakened by pre-existing fatigue. A major contributory factor was the absence of any routine check item which might otherwise have detected the onset of failure at an early stage."
Accident investigation:
 |
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Classification:
Engine separationForced landing on runway
Sources:
» NTSBPhotos
Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from New York-John F. Kennedy International Airport, NY to London-Heathrow Airport as the crow flies is 5501 km (3438 miles).
Distance from New York-John F. Kennedy International Airport, NY to London-Heathrow Airport as the crow flies is 5501 km (3438 miles).
This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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