AD 2021-08-10

This AD is effective May 25, 2021.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of May 25, 2021.

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; telephone 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 at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-1167.

Manuel Hernandez, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5256; fax: 562-627-5210; email: Manuel.F.Hernandez@faa.gov.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all The Boeing Company Model DC-10-10, DC-10-10F, DC-10-15, DC-10-30, DC-10-30F (KC-10A and KDC-10), DC-10-40 and DC-10-40F airplanes; and Model MD-10-10F and MD-10-30F airplanes. The NPRM published in the Federal Register on January 15, 2021 (86 FR 3885). The NPRM was prompted by a report that an operator found a crack in the upper flange of the pylon aft bulkhead bracket. In the NPRM, the FAA proposed to require a general visual inspection of the left and right wing pylon at the aft bulkhead bracket for any lockbolt and collar; repetitive surface and open hole ETHF inspections of the left and right wing pylon at the aft bulkhead bracket for any cracking; and applicable on-condition actions. The FAA is issuing this AD to address possible cracking of the wing pylon at the aft bulkhead bracket, which could result in the inability of the pylon to sustain limit load and adversely affect the structural integrity of the airplane.

The FAA received a comment from The Air Line Pilots Association, International (ALPA) who supported the NPRM without change.

The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator.

The FAA reviewed Boeing Alert Requirements Bulletin DC10-54A111 RB, dated June 26, 2020. The service information describes procedures for a general visual inspection of the left and right wing pylon at the aft bulkhead bracket for any lockbolt and collar; repetitive surface and open hole ETHF inspections of the left and right wing pylon at the aft bulkhead bracket for any cracking; and applicable on-condition actions. On-condition actions include modifying any aft bulkhead bracket that has a lockbolt and collar, and repair or replacement of the aft bulkhead bracket.

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 ADDRESSES.

The FAA estimates that this AD affects 103 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 modifications that would be required. The FAA has no way of determining the number of aircraft that might need these on-condition modifications:

The FAA has received no definitive data on which to base the cost estimates for the on-condition repairs and replacements specified in this AD.

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.

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 adding the following new airworthiness directive: