Narrative:

At xa:48Z dispatch contacted the cockpit via ACARS that MEL 28-xxb would be removed and replaced with MEL 28-xxa. MEL 28-xxb requires the aircrew to do minimal procedures but requires maintenance to deactivate the trim pipe isolation valve. MEL 28-xxb keeps the trim tank empty and cg is accounted for on the tps (temporary protection system). MEL 28-xxa requires maintenance to manually allow fuel into the trim tank when refueling. This MEL also requires the flight crew to manually transfer fuel from the trim tank to the main tanks while in flight. This manual refueling method was not accomplished and was not verified with a maintenance aml entry signifying accomplishment which is required at each refueling of the trim tank until restoration is made. Therefore; no manual fuel transferring occurred from the cockpit. The relief pilot brought this to the attention of the two mechanics working the issue. The relief pilot was told; 'it is taken care of'. At xb:00Z dispatch contacted the cockpit via ACARS once again to report that MEL 28-xxb had been removed and MEL 28-xxa had been added. The final resolution by the mechanics working the issue was to overwrite the 'B' with a 'a' in the logbook write up and the E693 placard. With the correct release fuel in the main tanks only (no trim tank fuel) and with all logbook paperwork signed off we received a load closeout at xb:11Z. This load closeout was as expected from the tps with a stab nose up trim of 6.0. We received a load closeout revision 01 at xb:16Z which included minimal changes. We pushed from the gate at xb:31Z. Taxiing out we received load closeout revision 02 at xb:42Z. Revision 02 indicated a large adjustment to stab nose up trim to 4.0 with minimal other changes. This new change was discussed among the fos (first officers) at that time. While at cruise altitude the relief pilot searched to ensure that we were compliant with the amount of fuel that needed to be in the trim tank since MEL 28-xxa would control cg by adding fuel to the trim tank and be manually transferred by the flight deck crew. The following is an excerpt from the A330 performance manual; loading section; pg 2-9: trim tank loading guidance 2.4.2 A330. The chart below is the trim tank quantity chart from airbus. Note that only trim tank variables exist between two ranges; 80.4-85.7 K lbs.; and 162.0- 168.7K lbs. In all other situations; the trim tank should read either 0 (fuel load up to 80.4) or 5;300 lbs. (Fuel load between 85.7- 162.0 K lbs.). A variance of +/- 300 lbs. In the trim tank is acceptable. The trim tank maximum planned load will be 10.7K lbs.; but as the chart shows; the quantity does not begin to increase above 5;300 lbs. Until the total planned fuel load exceeds 162;000 lbs.under the guidance of MEL 28-xxa and the performance manual; maintenance was required to manually fuel 5300 pounds of fuel in the trim tank. The flight crew would then manually transfer this fuel in flight. This did not happen. Our release fuel was 123;281 lbs. And per the performance manual loading section our aircraft should have had 5;300 lbs of fuel in the trim tank. The MEL stated nothing about this requirement. It is now obvious that dispatch and maintenance knew nothing about this also! This event occurred because the MEL for MEL 28-xxa and B is poorly written so the involved parties (cockpit; dispatch; and maintenance) were not aware of the fueling requirements associated with either of these MEL sections. The location of the trim tank loading guidance is in a very uncommon publication for an MEL compliance. Since the MEL is used in a non-normal environment this trim tank loading guidance should also be located where the non-normal environment MEL is resolved. MEL 28-xxa needs to be re-written to include the fueling quantity as described in A330 performance manual; loading--trim tank loading guidance. This information is obviously not available in the MEL (for dispatchers and maintainers) but only available to pilots in a very uncommon location.

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Original NASA ASRS Text

Title: A330 flight crew reported that a fuel system MEL was removed and replaced with a different fuel system MEL; causing a greater work load for the flight crew.

Narrative: At XA:48Z Dispatch contacted the cockpit via ACARS that MEL 28-XXB would be removed and replaced with MEL 28-XXA. MEL 28-XXB requires the aircrew to do minimal procedures but requires maintenance to deactivate the trim pipe isolation valve. MEL 28-XXB keeps the trim tank empty and CG is accounted for on the TPS (Temporary Protection System). MEL 28-XXA requires maintenance to manually allow fuel into the trim tank when refueling. This MEL also requires the flight crew to manually transfer fuel from the trim tank to the main tanks while in flight. This manual refueling method was NOT accomplished and was NOT Verified with a Maintenance AML entry signifying accomplishment which is required at each refueling of the trim tank until restoration is made. Therefore; no manual fuel transferring occurred from the cockpit. The relief pilot brought this to the attention of the two mechanics working the issue. The relief pilot was told; 'it is taken care of'. At XB:00Z Dispatch contacted the cockpit via ACARS once again to report that MEL 28-XXB had been removed and MEL 28-XXA had been added. The final resolution by the mechanics working the issue was to overwrite the 'B' with a 'A' in the logbook write up and the E693 placard. With the correct release fuel in the main tanks only (no trim tank fuel) and with all logbook paperwork signed off we received a load closeout at XB:11Z. This load closeout was as expected from the TPS with a stab nose up trim of 6.0. We received a load closeout revision 01 at XB:16Z which included minimal changes. We pushed from the gate at XB:31Z. Taxiing out we received load closeout revision 02 at XB:42Z. Revision 02 indicated a large adjustment to stab nose up trim to 4.0 with minimal other changes. This new change was discussed among the FOs (first officers) at that time. While at cruise altitude the relief pilot searched to ensure that we were compliant with the amount of fuel that needed to be in the trim tank since MEL 28-XXA would control CG by adding fuel to the trim tank and be manually transferred by the flight deck crew. The following is an excerpt from the A330 Performance Manual; Loading Section; Pg 2-9: Trim Tank Loading Guidance 2.4.2 A330. The chart below is the trim tank quantity chart from Airbus. Note that only trim tank variables exist between two ranges; 80.4-85.7 K lbs.; and 162.0- 168.7K lbs. In all other situations; the trim tank should read either 0 (fuel load up to 80.4) or 5;300 lbs. (fuel load between 85.7- 162.0 K lbs.). A variance of +/- 300 lbs. in the trim tank is acceptable. The trim tank maximum planned load will be 10.7K lbs.; but as the chart shows; the quantity does not begin to increase above 5;300 lbs. until the total planned fuel load exceeds 162;000 lbs.Under the guidance of MEL 28-XXA and the Performance Manual; Maintenance was required to manually fuel 5300 pounds of fuel in the trim tank. The flight crew would then manually transfer this fuel in flight. This did not happen. Our release fuel was 123;281 lbs. and per the Performance Manual Loading Section our aircraft should have had 5;300 lbs of fuel in the trim tank. The MEL stated NOTHING about this requirement. It is now obvious that Dispatch AND Maintenance knew NOTHING about this also! This event occurred because the MEL for MEL 28-XXA and B is poorly written so the involved parties (cockpit; Dispatch; and Maintenance) were not aware of the fueling requirements associated with either of these MEL sections. The location of the trim tank loading guidance is in a very uncommon publication for an MEL compliance. Since the MEL is used in a non-normal environment this trim tank loading guidance should also be located where the non-normal environment MEL is resolved. MEL 28-XXA needs to be re-written to include the fueling quantity as described in A330 Performance Manual; Loading--Trim Tank Loading Guidance. This information is obviously not available in the MEL (for dispatchers and maintainers) but only available to pilots in a very uncommon location.

Data retrieved from NASA's ASRS site 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.