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| Date: | Monday 2 May 1988 |
| Time: | 19:16 LT |
| Type: |  Boeing 747-123 |
| Owner/operator: | United Airlines |
| Registration: | N157UA |
| MSN: | 20106/79 |
| Year of manufacture: | 1970 |
| Total airframe hrs: | 39950 hours |
| Engine model: | P&W JT9D-7A |
| Fatalities: | Fatalities: 0 / Occupants: 258 |
| Other fatalities: | 0 |
| Aircraft damage: | Minor |
| Category: | Serious incident |
| Location: | Nr Tokyo, PO -
 United States of America
|
| Phase: | En route |
| Nature: | Passenger - Scheduled |
| Departure airport: | Los Angeles International Airport, CA (LAX/KLAX) |
| Tokyo | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
UNITED FLT 97 EXPERIENCED INDICATIONS OF UNEVEN FUEL FLOW FROM MAIN TANKS 2 AND 3 AT FL360 BEGINNING ABOUT 4- HOURS AFTER DEPARTURE ON AN 11-HOUR TRANSPACIFIC FLIGHT. THE FUEL SYSTEM HAD BEEN SET UP FOR ALL ENGINE FEED FROM THE NOS 2 AND 3 TANKS. ALTHOUGH IT WAS LATER ESTABLISHED THAT THE NUMBER 2 CROSSFEED VALVE FAILED IN THE CLOSED POSITION, THE S/O INFORMED THE CAPT THAT THE INTRANSIT LIGHT HAD ILLUMINATED WHEN THE VALVE SELECTOR WAS MOVED TO THE CLOSED POSITION - INDICATING NORMAL CROSSFEED VALVE OPERATION. FUEL SYSTEM PROBLEM WAS MISDIAGNOSED AS A PROBLEM OF FAULTY FUEL GAGE INDICATIONS. FUEL MONITORING INDICATED INSUFFICIENT FUEL FLOW FROM NO 2 TANK WHEN CROSSFEEDING. ENGS 1, 3, AND 4 FLAMED OUT WHEN FUEL WAS EXPENDED FROM ALL TANKS EXCEPT NO 2. EMERGENCY DESCENT WAS MADE TO DESTINATION TOKYO-NARITA AIRPORT. CREW REPORTED THEY USED FLAPS-20, BUT DFDR SHOWED FLAPS-1 WAS USED FOR LANDING. 3 TIRES BLEW ON LANDING. ALL 3 FLIGHTCREW QUALIFIED IN THE B-747 IN THE 13-MONTHS BEFORE THE INCIDENT.
Probable Cause:
Accident investigation:
 |
|
Sources:
NTSB DCA88IA056
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 25-Mar-2024 18:48 | ASN Update Bot | Added |
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