MD80 crew had a suspected fuel leak in the right fuel system.

Attributes
ACN	571753
Time
Date	200301
Day	Thu
Local Time Of Day	0601 To 1200
Place
State Reference	SD
Altitude	msl single value : 31000
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zmp.artcc
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	IFR
Aircraft 2
Controlling Facilities	artcc : zmp.artcc
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	571753
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : fuel quantity indicators other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance controller : provided flight assist flight crew : declared emergency flight crew : diverted to another airport flight crew : landed in emergency condition other
Consequence	other other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

The right wing fuel quantity was significantly lower than left wing fuel quantity. Wing tanks should have been fairly even and near full since there was fuel in the center tank and that center tank fuel should have been supplying both engines since all boost pumps were on (normal procedures). As the center tank quantity was not increasing, we suspected a fuel leak. We got out the operating manual and went to the fuel section to read the 'in-flight fuel loss' abnormal. The abnormal led us to inspect the wing from the cabin to check for a wing leak. Inspection of the right wing from the cabin revealed no leak. Also, aileron trim was increasing verifying an actual imbal. This led us to believe that the leak was engine related as indicated by the abnormal. As we informed ATC of our problem, an aircraft had us visually and reported that they saw something coming from the tail of our aircraft. A vapor from the tail that they said may or may not be a contrail. This supported our suspicion that the loss of fuel from the right tank was from the engine. We proceeded through the abnormal, which led us to 'land at nearest suitable airport' and the QRH procedure 'engine fire/damage/separation.' I declared an emergency with ATC, shut down the engine, and diverted to sioux falls, sd, which was 90 NM off our tail. We landed 2000 pounds overweight. After landing, the engine and tail area were inspected by crash fire rescue equipment on the runway for signs of a fuel leak. No leak was seen and I taxied to the gate and parked.

Original NASA ASRS Text

Title: MD80 CREW HAD A SUSPECTED FUEL LEAK IN THE R FUEL SYS.

Narrative: THE R WING FUEL QUANTITY WAS SIGNIFICANTLY LOWER THAN L WING FUEL QUANTITY. WING TANKS SHOULD HAVE BEEN FAIRLY EVEN AND NEAR FULL SINCE THERE WAS FUEL IN THE CTR TANK AND THAT CTR TANK FUEL SHOULD HAVE BEEN SUPPLYING BOTH ENGS SINCE ALL BOOST PUMPS WERE ON (NORMAL PROCS). AS THE CTR TANK QUANTITY WAS NOT INCREASING, WE SUSPECTED A FUEL LEAK. WE GOT OUT THE OPERATING MANUAL AND WENT TO THE FUEL SECTION TO READ THE 'INFLT FUEL LOSS' ABNORMAL. THE ABNORMAL LED US TO INSPECT THE WING FROM THE CABIN TO CHK FOR A WING LEAK. INSPECTION OF THE R WING FROM THE CABIN REVEALED NO LEAK. ALSO, AILERON TRIM WAS INCREASING VERIFYING AN ACTUAL IMBAL. THIS LED US TO BELIEVE THAT THE LEAK WAS ENG RELATED AS INDICATED BY THE ABNORMAL. AS WE INFORMED ATC OF OUR PROB, AN ACFT HAD US VISUALLY AND RPTED THAT THEY SAW SOMETHING COMING FROM THE TAIL OF OUR ACFT. A VAPOR FROM THE TAIL THAT THEY SAID MAY OR MAY NOT BE A CONTRAIL. THIS SUPPORTED OUR SUSPICION THAT THE LOSS OF FUEL FROM THE R TANK WAS FROM THE ENG. WE PROCEEDED THROUGH THE ABNORMAL, WHICH LED US TO 'LAND AT NEAREST SUITABLE ARPT' AND THE QRH PROC 'ENG FIRE/DAMAGE/SEPARATION.' I DECLARED AN EMER WITH ATC, SHUT DOWN THE ENG, AND DIVERTED TO SIOUX FALLS, SD, WHICH WAS 90 NM OFF OUR TAIL. WE LANDED 2000 LBS OVERWT. AFTER LNDG, THE ENG AND TAIL AREA WERE INSPECTED BY CFR ON THE RWY FOR SIGNS OF A FUEL LEAK. NO LEAK WAS SEEN AND I TAXIED TO THE GATE AND PARKED.

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.