United Airlines

United has the following comments; (1) The proposed AD would require installing a fiberglass reinforcement overcoat to the top surface of the aft MEC drip shield gutters and installing cargo liner. This is different from the S.B. The S.B. installs the fiberglass overcoat to the underside of the bonded seams. (2) On S.B. Figures 1 and 5, on all steps indicating quantity of fasteners, propose to add a note be that quantity of fasteners may vary due to configuration differences. Adding this note, would save the operators a lot of time in dealing with variances in the quantity of fasteners called out in the S.B. as against what is on the airplane. On the last AD 2012-15-10, 747-400 MEC Drip Shield Repair (Boeing S.B. 747-25A3555, revision 1), United is already on its six (6) AMOC due to these variances.