AD 96-26-52 R1

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by revising AD 96-26-52, amendment 39-9868 (62 FR 302, January 3, 1997), which is applicable to certain Boeing Model 747 series airplanes, was published in the Federal Register on February 12, 1997 (62 FR 6499). That action proposed to continue to require repetitive inspections of the access doors to the midspar/spring beam fuse pins on all engine pylons to detect cracks on the external surface, repetitive inspections of each midspar/spring beam fuse pin to detect if it protrudes beyond its mating nut by a specified distance, and repair of any discrepancy found. That action also proposed to increase the intervals between inspections of the access doors and each midspar/spring beam fuse pin, and consequently decrease the frequency of inspections.

Comments on the Proposal

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the two comments received.

One commenter supports the proposal.

One commenter requests that the proposed frequency of repetitive inspections of the access doors to each midspar/spring beam fuse pin and each fuse pin be altered to 5,000 hours time-in- service, or 15 months, whichever occurs first; this interval is equivalent to the maintenance interval specified in the operator's Maintenance Review Board (MRB) report. The commenter considers that adoption of the FAA's proposed interval of 1,000 landings or 18 months, whichever occurs first, would require certain operators to schedule special times for the accomplishment of this inspection.

The FAA concurs that the compliance times can be revised somewhat. The FAA's intent was that inspections be conducted during a regularly scheduled maintenance visit for the majority of the affected fleet, when the airplanes would be located at a base where special equipment and trained personnel would be readily available, if necessary. Based on the information supplied by the commenter, the FAA recognizes that 5,000 hours time-in-service corresponds closely to the interval specified in the operators' MRB report. In light of this, the FAA has revised paragraphs (a)(1)(i), (a)(2)(i), and (a)(2)(ii) of the final rule to reflect a compliance time of "intervals not to exceed 1,000 landings or 5,000 hours time-in-service, whichever occurs later, but not to exceed 18 months." The FAA does not consider that this revision of the compliance time will adversely affect safety.

Conclusion

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

There are approximately 459 Boeing Model 747 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 44 airplanes of U.S. registry will be affected by this AD.

It will take approximately 4 work hours per airplane to accomplish each cycle of required inspections, at an average rate of $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $10,560 per inspection cycle, or $240 per airplane, per inspection cycle. (By increasing the intervals between inspections, this AD will result in inspections being conducted less frequently than is now required.)

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact

The regulations adopted herein will not have substantial direct effects on the States, on the relationshipbetween the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39 - AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 - (Amended) 2. Section 39.13 is amended by removing amendment 39-9868 (62 FR 302, January 3, 1997), and by adding a new airworthiness directive (AD), amendment 39-10027, to read as follows: