AD 2020-15-14

This AD is effective September 3, 2020.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of September 3, 2020.

For service information identified in this final rule, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; phone: 562-797-1717; internet: https://www.myboeingfleet.com. You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. It is also available on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-0208.

Eric Lin, Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-3523; email: eric.lin@faa.gov.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2015-13-06, Amendment 39-18193 (80 FR 44835, July 28, 2015) (“AD 2015-13-06”). AD 2015-13-06 applied to certain The Boeing Company Model 747-400 and 747-400F series airplanes. The NPRM published in the Federal Register on March 30, 2020 (85 FR 17510). The NPRM was prompted by a report that an operator found a cracked longeron extension fitting on an airplane not included in the applicability of AD 2015-13-06. The NPRM proposed to continue to require repetitive inspections of the longeron extension fittings for cracking; repetitive HFEC inspections of any modified, repaired, or replaced longeron extension fitting for cracking; and applicable on-condition actions. The NPRM also proposed to add Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400D, 747SR, and 747SP series airplanes to the applicability, and for those additional airplanes, repetitive inspections of the longeron extension fittings for cracking and repair if necessary. The FAA is issuing this AD to address cracks in the longeron extension fittings, which can become large and adversely affect the structural integrity of the airplane.

The FAA gave the public the opportunity to participate in developing this AD. The following presents the comments received on the NPRM and the FAA's response to each comment.

Boeing stated that it had no comment regarding the NPRM and Hasan Ashour expressed support for the NPRM.

Addison Hull requested that the FAA expand the applicability of the NPRM to include all airplanes. The commenter expressed concern that the NPRM only identified 67 affected airplanes. The commenter also pointed out their belief that all airplanes should have the same minimum requirements, and that this method would be more efficient compared with publishing specific rules to mandate the inspection and maintenance of other types of airplanes that are not affected by the NPRM.

The FAA disagrees with the request. The FAA issues ADs to address potential unsafe conditions in airplanes with similar designs. The FAA has worked closely with the design approval holder (DAH) to determine the group of affected airplanes that may develop this particular unsafe condition. The group of affected airplanes for this particular unsafe condition is an expansion to the group of airplanes addressed by AD 2015-13-06. Therefore, the FAA believes that the entire number of affected airplanes have been captured by this AD. This AD has not been changed in this regard.

The FAA reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD as proposed, except for minor editorial changes. The FAA has determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM.

The FAA reviewed Boeing Service Bulletin 747-53A2860, Revision 3, dated November 11, 2019. This service information describes procedures for repetitive inspections of the longeron extension fittings for cracking; repetitive HFEC inspections of any modified, repaired, or replaced longeron extension fitting for cracking; and applicable on-condition actions. On-condition actions include replacement, repair, and modification. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

The FAA estimates that this AD affects 67 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

The FAA estimates the following costs to do any necessary on-condition actions that would be required. The FAA has no way of determining the number of aircraft that might need these on-condition actions:

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

The FAA has determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Will not affect intrastate aviation in Alaska, 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.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 2015-13-06, Amendment 39-18193 (80 FR 44835, July 28, 2015), and adding the following new AD: