All Nippon Airways

All Nippon Airways (ANA) has reviewed Supplemental NPRM 2007-NM-357-AD and would like to comment on the proposed AD. <Reference> /A/ Supplemental NPRM 2007-NM-357-AD /B/ Boeing Alert Service Bulletin 747-28A2330, dated April 2, 2012 /C/ B747-400 MPD TASK 28-22-04(D621U400) <Comment> ANA has reviewed Ref/A/ proposed AD, Ref/B/ SB and Ref/C/ MPD task. The proposed AD paragraph (g) mandates operation check and corrective actions in accordance with ref/B/ SB. On the other hand, Ref/C/ task is almost same with Ref/B/ SB. Many operators have already been performing Ref/C/ maintenance task at interval recommended by Ref/C/MPD (6 years). If Ref/A/ mandates Ref/C/ MPD task with interval of 30,000 flight hours or 6years whichever occurs first, which will satisfy the requirement of Ref/A/ proposed AD. ANA would like FAA to approve Ref/C/ MPD task as an alternative method of compliance (AMOC) if only the interval satisfies the requirement of Ref/A/ proposed AD to reduce extra work.