Flight Crew Air Transport Pilot (ATP)
Distraction; Human-Machine Interface; Workload; Training / Qualification
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Fuel Issue
Flight Crew Took Evasive Action; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Landed in Emergency Condition; General Declared Emergency
Aircraft
At cruise enroute; we noted the fuel slowly feeding from the main (wing) tanks with the center fuel pumps ON. During a 16 minute period; we burned a total of 1;900 LBS of fuel. All should have come from the center tank. In fact only 1;200 fed from the center tank and 700 LBS fed from the wings (mains). We ran the QRH procedure 'fuel not feeding from center tank'. Using the checklist; we discovered that leaving the left main (wing) tank pumps OFF while leaving the center tank and right main (wing) tanks ON allowed us to use center tank fuel and maintain fuel balance between wing (main) tanks. We calculated that we could make our destination with reserve fuel and alternate fuel even if the center tank fuel became unusable. We continued to the filed destination. We contacted Dispatch and Maintenance via radio. Dispatch calculated we would be within both Center of Gravity (CG) and Zero Fuel Weight (ZFW) limits with arrival fuel of approximately 3;500 LBS in center tank and 7;000 LBS in each wing tank. We declared an emergency since we had a problem with the fuel system even though we expected a normal landing. We briefed the Flight Attendants. I briefed the passengers on the PA to assure them in case they noticed emergency vehicles near the aircraft following our arrival. We made a normal approach and landing. We terminated the emergency following landing and made a normal taxi to the gate.
A MD82's fuel transfer system did not properly pump fuel from the center tank to the engines until the wing tank boost pumps were turned OFF. Because of the fuel and CG imbalance an emergency was declared for landing.