Commercial Fixed Wing
Flight Crew Last 90 Days 240; Flight Crew Total 30000; Flight Crew Type 12000
Communication Breakdown; Troubleshooting; Confusion; Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural MEL / CDL
General Maintenance Action
MEL; Aircraft; Chart Or Publication; Human Factors; Logbook Entry; Manuals
I arrived at the aircraft and discovered the right center fuel boost pump inoperative and on MEL 28-02-02R. After reading the MEL it was my belief that the incorrect MEL was reflected for the right center fuel boost pump and that the correct MEL for the right center fuel boost pump was MEL 28-02-01R. The current fuel load on the aircraft was 27.8. (8.9/10.0/8.9). I called Maintenance through Dispatch and with the Assistant Chief Pilot on the line we discussed the MEL at length (until 21-minutes after push time). I advocated for MEL 28-02-01R and Maintenance held hard and fast to their issue MEL 28-02-02R. The Assistant Chief Pilot supported the position of Maintenance. I advocated that if the pump failed and fuel was burned from the wing fuel tanks the Center of Gravity (CG) of the aircraft would be in question since the normal fuel burn sequence was being violated. Maintenance told me a correction was applied to the Zero Fuel Weight (ZFW) to account for failure of the pump. I also pointed out to Maintenance and the Assistant Chief Pilot that by operating the aircraft with center tank fuel; with one center tank [pump] inoperative; that this places me operating under a Non-Normal Procedure of the Limitations section of the Flight Manual. I was told by Maintenance and the Assistant Chief Pilot that the MEL accounted for this and allowed operation under Non-Normal Procedures of the MEL.My concern was that if the last operating [center tank] pump failed; the center tank fuel was unusable. I was told by Maintenance that the Engine Driven Pumps (EDP) would suck the fuel out of the center tanks. I corrected Maintenance and explained the center fuel tank had no bypass valve and suction feed from that tank was not available. The Assistant Chief Pilot was unclear on this issue as he fly's multiple aircraft and could not recall the B-737 systems. After much discussion and being told by Maintenance that they routinely issue this MEL for this situation (Right Center Boost Pump inoperative) and also being told that they almost never use MEL 28-02-01; that I could refuse the aircraft or fly it as they deemed airworthy; as did the Assistant Chief Pilot.I informed Maintenance and the Assistant Chief Pilot I would fly the aircraft as dispatched with the understanding that I would immediately divert if the second; center fuel tank pump failed. Multiple immediate airfields for diversion were available on this leg. En route as the center tank burned down; I realized that in order to comply with Airworthiness Directives (AD) AD 2002-19-52; and AD 2002-24-51 with Alternate Method of Compliance (AMOCs) 140S-02-376 and 140S-03-189; it would be necessary to turn-off the center tank with 5;000 LBS of fuel remaining. I requested from Dispatch to query the Maintenance and the Assistant Chief Pilot how I was to comply with the center tank fuel usage procedures and was instructed via ACARS by Dispatch. The Assistant Chief Pilot and Maintenance said to use the left pump until the low pressure light comes on; than switch the pump off.The Flight Manual limitations clearly state that the limitations contained in this AD supersede any conflicting basic Aircraft Flight Manual limitations. However the Flight Manual is not clear on the role of an MEL. I still believe an incorrect MEL was issued for the inoperative right boost pump. What if this leg had been [longer] and the pump or and electrical system had failed that rendered the other center tank boost pump inoperative. A large amount of fuel would have been unusable to the crew. Also though not stated in the Flight Manual I do not believe the intent of AD 2002-19-52; and AD 2002-24-51 with AMOCs 140S-02-376 and 140S-03-189 was to operate on an MEL and disregard the direction provided therein.
A Line Captain describes why he believes MEL 28-02-01R should have been applied to their B737-800 aircraft for an inoperative Right Center Fuel Boost Pump. Maintenance Control had applied MEL 28-02-02R. Compliance with Airworthiness Directives; AD 2002-19-52 and 2002-24-51 that superseded their Aircraft Flight Manuals was also raised.