DC10 crew had fuel imbal exceeding limits in ZLA class a airspace.

Attributes
ACN	510043
Time
Date	200105
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : las.airport
State Reference	NV
Altitude	msl single value : 35000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zla.artcc
Operator	common carrier : air carrier
Make Model Name	DC-10 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : atp
Experience	flight time last 90 days : 150 flight time total : 17000 flight time type : 15000
ASRS Report	510043
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance non adherence : published procedure other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : fuel guages other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : declared emergency flight crew : landed in emergency condition flight crew : diverted to another airport
Consequence	other other
Factors
Maintenance	contributing factor : schedule pressure performance deficiency : fault isolation performance deficiency : testing performance deficiency : repair
Supplementary
Problem Areas	Company Aircraft Maintenance Human Performance
Primary Problem	Maintenance Human Performance

Narrative:

Approaching las en route dtw-lax, a lateral fuel imbal of approximately 10000 pounds was observed. Just prior to this, the fuel had been very evenly balanced. A fuel leak from #1 fuel tank was suspected, as #1 quantity was approximately 10000 pounds less than #3 tank. The so did a test of all fuel quantity gauges, tank fill valves, and fill valve lights, and began a xfer of fuel from #1 to #1 fuel tank. Lax WX was checked and observed to be 800 ft overcast 2 mi visibility. Las was clear. As the lateral imbal did not immediately rectify itself during fuel xfer back to tank #1, and we were uncertain of the problem and suspected a fuel leak, an emergency was declared and landing made at las, nv. Inspection from outside the aircraft showed no visible leaks. Conversation with maintenance control revealed a history of uncommanded fuel xfer.

Original NASA ASRS Text

Title: DC10 CREW HAD FUEL IMBAL EXCEEDING LIMITS IN ZLA CLASS A AIRSPACE.

Narrative: APCHING LAS ENRTE DTW-LAX, A LATERAL FUEL IMBAL OF APPROX 10000 LBS WAS OBSERVED. JUST PRIOR TO THIS, THE FUEL HAD BEEN VERY EVENLY BALANCED. A FUEL LEAK FROM #1 FUEL TANK WAS SUSPECTED, AS #1 QUANTITY WAS APPROX 10000 LBS LESS THAN #3 TANK. THE SO DID A TEST OF ALL FUEL QUANTITY GAUGES, TANK FILL VALVES, AND FILL VALVE LIGHTS, AND BEGAN A XFER OF FUEL FROM #1 TO #1 FUEL TANK. LAX WX WAS CHKED AND OBSERVED TO BE 800 FT OVCST 2 MI VISIBILITY. LAS WAS CLR. AS THE LATERAL IMBAL DID NOT IMMEDIATELY RECTIFY ITSELF DURING FUEL XFER BACK TO TANK #1, AND WE WERE UNCERTAIN OF THE PROB AND SUSPECTED A FUEL LEAK, AN EMER WAS DECLARED AND LNDG MADE AT LAS, NV. INSPECTION FROM OUTSIDE THE ACFT SHOWED NO VISIBLE LEAKS. CONVERSATION WITH MAINT CTL REVEALED A HISTORY OF UNCOMMANDED FUEL XFER.

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.