B757 flight crew notes fuel discrepancy in cruise and after troubleshooting; elects to divert.

Attributes
ACN	773617
Time
Date	200802
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	msl single value : 32000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zzz.artcc
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
ASRS Report	773617
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	773618
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : fmc other flight crewa
Resolutory Action	flight crew : diverted to another airport flight crew : landed as precaution
Consequence	other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

After reaching cruise altitude; we noticed a difference between fuel onboard and fuel required. Subsequent waypoints along our route indicated an increasing difference between fuel required and actual fuel onboard. Utilizing the QRH in-flight engine fuel leak procedure; as well as a visual inspection from the cabin by myself; we were unable to positively identify any engine fuel leak versus a wing tank leak or fuel indication error. Captain made the decision to divert to ZZZ. ATC cleared us direct from present position to ZZZ international airport. After landing and engine shutdown; maintenance verified an engine fuel leak.

Original NASA ASRS Text

Title: B757 FLT CREW NOTES FUEL DISCREPANCY IN CRUISE AND AFTER TROUBLESHOOTING; ELECTS TO DIVERT.

Narrative: AFTER REACHING CRUISE ALT; WE NOTICED A DIFFERENCE BTWN FUEL ONBOARD AND FUEL REQUIRED. SUBSEQUENT WAYPOINTS ALONG OUR RTE INDICATED AN INCREASING DIFFERENCE BTWN FUEL REQUIRED AND ACTUAL FUEL ONBOARD. UTILIZING THE QRH INFLT ENG FUEL LEAK PROC; AS WELL AS A VISUAL INSPECTION FROM THE CABIN BY MYSELF; WE WERE UNABLE TO POSITIVELY IDENT ANY ENG FUEL LEAK VERSUS A WING TANK LEAK OR FUEL INDICATION ERROR. CAPT MADE THE DECISION TO DIVERT TO ZZZ. ATC CLRED US DIRECT FROM PRESENT POS TO ZZZ INTL ARPT. AFTER LNDG AND ENG SHUTDOWN; MAINT VERIFIED AN ENG FUEL LEAK.

Data retrieved from NASA's ASRS site as of May 2009 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.