A B747 in cargo confign diverted due to insufficient fuel in #3 main tank.

Attributes
ACN	362830
Time
Date	199703
Day	Thu
Local Time Of Day	0001 To 0600
Place
Locale Reference	atc facility : tvc
State Reference	MI
Altitude	agl bound lower : 0 agl bound upper : 0 msl bound lower : 31000 msl bound upper : 35000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B747-C/F
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Route In Use	enroute airway : chi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 100 flight time total : 13000 flight time type : 1200
ASRS Report	362830
Person 2
Affiliation	company : air carrier
Function	observation : company check pilot oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp
Events
Anomaly	aircraft equipment problem : critical non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other flight crewa other other : unspecified cockpit
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

Upon level off at FL310, flight engineer discovered #3 main tank fuel quantity gauge stuck at 61000 pounds. Since #3 and #2 are identical, he did some troubleshooting and swapped quantity gauges. Upon discovering that the problem was neither gauge, he swapped them back to original position. #3 gauge then stuck at 46000 pounds. About 4 1/2 hours into planned 6 hour flight, #3 forward boost pump low pressure light came on. Aircraft attitude was approximately 2 1/2 degrees nose up. In order to check fuel quantity in #3 tank, #3 tank jettison/transfer pumps were turned on. Low pressure lights came on for those pumps also, indicating fuel quantity in that tank to be below standpipe level. Quantity gauging system for #3 tank had been worked on at home station on feb/xx/96, changing sensing harness and other components. There were no logbook entries about this system since that date. Destination was jfk, which was reporting instrument WX conditions. Upon discussion among the crew, and phone patch with company dispatch and maintenance control, flight diverted to ord. We landed with 31600 pounds, 2200 pounds in #3 main tank.

Original NASA ASRS Text

Title: A B747 IN CARGO CONFIGN DIVERTED DUE TO INSUFFICIENT FUEL IN #3 MAIN TANK.

Narrative: UPON LEVEL OFF AT FL310, FE DISCOVERED #3 MAIN TANK FUEL QUANTITY GAUGE STUCK AT 61000 LBS. SINCE #3 AND #2 ARE IDENTICAL, HE DID SOME TROUBLESHOOTING AND SWAPPED QUANTITY GAUGES. UPON DISCOVERING THAT THE PROB WAS NEITHER GAUGE, HE SWAPPED THEM BACK TO ORIGINAL POS. #3 GAUGE THEN STUCK AT 46000 LBS. ABOUT 4 1/2 HRS INTO PLANNED 6 HR FLT, #3 FORWARD BOOST PUMP LOW PRESSURE LIGHT CAME ON. ACFT ATTITUDE WAS APPROX 2 1/2 DEGS NOSE UP. IN ORDER TO CHK FUEL QUANTITY IN #3 TANK, #3 TANK JETTISON/TRANSFER PUMPS WERE TURNED ON. LOW PRESSURE LIGHTS CAME ON FOR THOSE PUMPS ALSO, INDICATING FUEL QUANTITY IN THAT TANK TO BE BELOW STANDPIPE LEVEL. QUANTITY GAUGING SYS FOR #3 TANK HAD BEEN WORKED ON AT HOME STATION ON FEB/XX/96, CHANGING SENSING HARNESS AND OTHER COMPONENTS. THERE WERE NO LOGBOOK ENTRIES ABOUT THIS SYS SINCE THAT DATE. DEST WAS JFK, WHICH WAS RPTING INST WX CONDITIONS. UPON DISCUSSION AMONG THE CREW, AND PHONE PATCH WITH COMPANY DISPATCH AND MAINT CTL, FLT DIVERTED TO ORD. WE LANDED WITH 31600 LBS, 2200 LBS IN #3 MAIN TANK.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.