Narrative:

During preflight I was concerned about having enough fuel based on somewhat vague writeup with discrepancy between left and right inner wing tanks at end of flight (left tank higher). Called maintenance to discuss fuel issue. He thought we were okay to go based on his conversation with contract maintenance and fueler. Had tank drip stick performed and added fuel as a precaution against a fuel quantity indicating problem. Told first officer to keep a very detailed fuel log. Discovered at first check that although fuel used for each engine was the same that the right wing fuel tank is showing less quantity. First officer looked up fuel leak checklist in FM. Sent jumpseater back to look at right side for secondary indications of a leak from engine or wing. No evidence found. First officer performed 30 minute fuel discrepancy procedure in accordance with flight manual fuel leak procedure. After 30 minutes found 500 lbs missing; less than the 660 lbs required by the flight manual to call it a leak. After much discussion about no secondary indications of leak and not meeting the flight manual definition of having a fuel leak; decided to continue and monitor with first officer performing another fuel discrepancy check. No change to the calculations. Later noticed fuel temperature differential between left and right outer fuel tanks. Wrote up all the above data to facilitate maintenance troubleshooting. Accidentally reported a loss of 21000 lbs/hr vs actual of 1000 lbs/hr. Maintenance queried and we corrected with a message reply on ACARS. Also; noted right engine fuel flow is fairly consistently 40-80 lbs/hr higher than left engine. Sent ACARS message to station and maintenance to have mechanic meet us at the gate so we could thoroughly debrief them on what we saw. At fuel check required at end of flight; did not meet requirement to write up (fuel used plus fob compared to fob at start of flight) difference of greater than 1000 lbs. Concerned about the way the flight manual fuel leak procedure is written and why the magic number to call it a valid fuel leak is 660 lbs in 30 minutes with no secondary indications of a leak.

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Original NASA ASRS Text

Title: An A320 flight crew described some confusion dealing with a possible fuel leak in flight.

Narrative: During preflight I was concerned about having enough fuel based on somewhat vague writeup with discrepancy between left and right inner wing tanks at end of flight (left tank higher). Called Maintenance to discuss fuel issue. He thought we were okay to go based on his conversation with contract maintenance and fueler. Had tank drip stick performed and added fuel as a precaution against a fuel quantity indicating problem. Told First Officer to keep a very detailed fuel log. Discovered at first check that although fuel used for each engine was the same that the right wing fuel tank is showing less quantity. First Officer looked up fuel leak checklist in FM. Sent jumpseater back to look at right side for secondary indications of a leak from engine or wing. No evidence found. First Officer performed 30 minute fuel discrepancy procedure IAW Flight Manual fuel leak procedure. After 30 minutes found 500 lbs missing; less than the 660 lbs required by the Flight Manual to call it a leak. After much discussion about no secondary indications of leak and not meeting the Flight Manual definition of having a fuel leak; decided to continue and monitor with First Officer performing another fuel discrepancy check. No change to the calculations. Later noticed fuel temperature differential between left and right outer fuel tanks. Wrote up all the above data to facilitate maintenance troubleshooting. Accidentally reported a loss of 21000 lbs/hr vs actual of 1000 lbs/hr. Maintenance queried and we corrected with a message reply on ACARS. Also; noted right engine fuel flow is fairly consistently 40-80 lbs/hr higher than left engine. Sent ACARS message to station and maintenance to have mechanic meet us at the gate so we could thoroughly debrief them on what we saw. At fuel check required at end of flight; did not meet requirement to write up (fuel used plus FOB compared to FOB at start of flight) difference of greater than 1000 lbs. Concerned about the way the Flight Manual fuel leak procedure is written and why the magic number to call it a valid fuel leak is 660 lbs in 30 minutes with no secondary indications of a leak.

Data retrieved from NASA's ASRS site as of April 2012 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.