Flight Crew Air Transport Pilot (ATP)
Distraction; Human-Machine Interface; Situational Awareness
Aircraft Equipment Problem Critical; Inflight Event / Encounter Fuel Issue
Flight Crew Overcame Equipment Problem
Company Policy; Human Factors; Aircraft
I was doing a random line check on the crew. They departed the gate with 1;400 pounds of fuel in the center tank. The Captain had the center fuel tank pumps on; as per SOP. Shortly after takeoff the left center tank fuel low pressure light illuminated. The Captain turned the pump off per the company procedure. The procedure does not mention opening the crossfeed. Fuel was then feeding the left engine from the left fuel tank and the right engine from the right fuel boost pump in the center tank. The crew was given a turn on the RNAV departure and an at or below crossing restriction which was not part of the RNAV departure; i.e.; they were busy. Shortly thereafter the fuel imbalance light came on. I informed the crew of their fuel issue.This is the second time I have seen this happen to a crew. The procedure should be all center pumps on or off or; if one is off; the crossfeed should be opened. Maybe with less than 2;000 pounds in the center tank the center pumps should be off for takeoff.
A B737NG Check Airman witnessed as the flight crew; following the company procedure; turned off the left center fuel tank pump shortly after takeoff when the its low pressure light illuminated but did not concurrently open the crossfeed valve...which is NOT directed by the procedure.  A short time later the fuel imbalance light illuminated and the reporter advised the crew of the cause; the left engine now burning from the left main tank and the right from the center tank via the right center tank boost pump.