A B767-200 HAS AN 8000 LB IMBAL BTWN L AND R WING DURING CRUISE BECAUSE THE FUEL XFEED VALVE IS LEFT ON AFTER PREFLT.

Narrative

FLYING FROM FLL TO LGA ARPT IN A B767-200; WE WERE USING FUEL MGMNT PROCS MANDATED BY FAA DUE TO CTR TANK PUMP PROBS. THESE PROCS REQUIRE THAT CTR TANK PUMPS REMAIN OFF WITH LESS THAN 5000 LBS OF FUEL IN CTR TANK. IN OUR CASE; 1300 LBS OF CTR FUEL WAS ON BOARD. THIS CAUSES A CONSTANT 'FUEL CONFIGN' DISCRETE WARNING AND EICAS MESSAGE. THIS EFFECTIVELY DELETES THE CONFIGN WARNING SYS. IN THIS CASE; IT BIT US BECAUSE THE XFEED VALVE HAD BEEN LEFT OPEN BY OVERNIGHT CREW; AND WE MISSED IT ON PREFLT. AFTER 2 1/2 HRS OF FLT WITH A CONFIGN WARNING THE WHOLE WAY WE NOTICED AN 8000 LB FUEL IMBAL; EXCEEDING THE 1500 LB MAX ALLOWABLE. CTL; HANDLING AND TRIM SETTING WERE SURPRISINGLY UNAFFECTED. I HAVE FOUND XFEEDS LEFT THIS WAY MANY TIMES AND ANECDOTAL EVIDENCE SUGGESTS THAT FUEL IMBALS ARE COMMONPLACE. IN MY OPINION; IF THE FUEL CONFIGN WARNING SYS IS TO BE INACTIVATED OPERATIONALLY; THERE SHOULD BE SOME INDICATIONS THAT THE XFEED IS LATCHED OPEN. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THEY HAD AN 8000 LB IMBAL BTWN THE L AND R WING OF THE ACFT BECAUSE THE FUEL XFEED VALVE HAD BEEN LEFT ON FROM THE PREVIOUS NIGHT. THEY MISSED THE PROPER SETTING OF THE VALVE DURING THEIR PREFLT. THEY WOULD ORDINARILY SEE A FUEL IMBAL DEVELOPING WITH THE EICAS MESSAGE ILLUMINATING. IN THIS CASE THOUGH; THE FUEL EICAS MESSAGE IS ON MOST OF THE TIME BECAUSE OF HAVING LESS THAN 1500 LBS IN THE CTR TANK WITH THE BOOST PUMPS OFF. THIS IS A RECENT PROCEDURAL CHANGE FOR ALL B767-200 ACFT. RPTR FURTHER STATED THAT THE FUEL XFEED VALVE IS OPENED DURING NIGHT TIME LAYOVER OF AN ACFT TO XFER FUEL OUT OF THE CTR TANK. FUEL DRAINS FROM THE WING TANKS INTO THE CTR TANK DURING PERIODS OF INACTIVITY. FUEL IS XFERRED OUT OF THE CTR TANK DURING LAYOVER PERIODS WITH THE USE OF THE XFEED VALVE. MAINT ACTIVATES THE VALVE; BUT DOES NOT RESET IT TO OFF MUCH OF THE TIME. ALTHOUGH THE FLC SHOULD CHK TO SEE THAT IT IS OFF DURING PREFLT; IT IS A DIFFICULT SWITCH TO EASILY DETERMINE WHAT POS IT IS IN; WHEN THERE IS AN ABUNDANCE OF LIGHT IN THE COCKPIT.