AD 2017-24-10

This AD is effective January 9, 2018.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of January 9, 2018.

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, Transport Standards Branch, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0340.

Muoi Vuong, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5205; fax: 562-627-5210; email: Muoi.Vuong@faa.gov.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain The Boeing Company Model 757-200, -200PF, and -300 series airplanes. The NPRM published in the Federal Register on May 19, 2017 (82 FR 22915). The NPRM was prompted by reports of cracking found at a certain fuselage frame inner chord. The NPRM proposed to require repetitive inspections for any cracking of a certain fuselage frame inner chord, identification of the material of a certain fuselage frame inner chord for certain airplanes, and applicable corrective actions. We are issuing this AD to detect and correct such cracks, which could result in the cargo door opening during flight, and result in rapid decompression of the airplane and the inability to sustain loads required for continued safe flight and landing.

We gave the public the opportunity to participate in developing this final rule. The following presents the comments received on the NPRM and the FAA's response to each comment. FedEx and United Airlines supported the NPRM.

Aviation Partners Boeing stated that accomplishing the supplemental type certificate (STC) ST01518SE does not affect the actions specified in the NPRM.

We concur with the commenter. We have redesignated paragraph (c) of the proposed AD (82 FR 22915, May 19, 2017) as paragraph (c)(1) of this AD and added paragraph (c)(2) to this AD to state that installation of STC ST01518SE does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01518SE is installed, a “change in product” alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of 14 CFR 39.17.

Boeing requested credit for previous accomplishment of the inspections in the NPRM. Boeing stated that Boeing Alert Service Bulletin 757-53A0101, dated November 8, 2016 (referenced in the NPRM as the appropriate source of service information), was published on November 8, 2016. Boeing commented that the effective date of the AD could be more than 7 months later than publication date of the service information. Boeing stated that it is likely that some Model 757 operators have already accomplished the inspections in accordance with the service information by the time the AD takes effect; therefore, the AD should provide credit for those inspections.

We acknowledge the commenter's request and agree to clarify. Paragraph (f) of this AD states to accomplish the actions within the compliance times specified, unless those actions are already done. Therefore, if operators have accomplished the inspections in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 757-53A0101, dated November 8, 2016, before the effective date of this AD, no further action is necessary. We have not revised this AD in this regard.

Delta Airlines (DAL) stated that it has concerns that the Accomplishment Instructions provided in Boeing Alert Service Bulletin 757-53A0101, dated November 8, 2016, do not include the corrective action. DAL commented that it will likely accomplish the inspections during 10-day maintenance visit checks, which would not be sufficient time for repair development if a crack is found. DAL also commented that operators would benefit from having corrective actions provided in the service information.

DAL stated that Boeing Alert Service Bulletin 757-53A0101, dated November 8, 2016, requires operators to repetitively inspect the inner chord, and the service information does not provide an option for an inspection should there be a previously installed FAA-approved repair. DAL commented that a previous repair of the frame has the potential to inhibit the ability to accomplish the inspection. DAL also commented that this leaves operators unable to accomplish the inspection as specified in Boeing Alert Service Bulletin 757-53A0101, dated November 8, 2016, and will require additional instruction as an AMOC.

We infer that DAL is requesting to delay issuance of the final rule until a revision of the service information includes repair data and alternative inspection instructions for previously accomplished repairs.

We disagree with the commenter's request. Including the repair data would delay issuance of this AD. Unique repair configurations may be necessary depending on the cracking that is detected. It is not possible to address each individual repair configuration in one AD. The various repair configurations and locations are unknown and therefore cannot be addressed at this time. Therefore, if cracking is found, it must be repaired before further flight using the corrective actions specified in Boeing Alert Service Bulletin 757-53A0101, dated November 8, 2016, or in accordance with paragraph (i)(2) of this AD. For previously approved repairs that prevent accomplishment of the inspections required by this AD, operators may request approval of an AMOC using the procedures in paragraph (j) of this AD. We have not revised this AD in this regard.

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule with the changes described previously and minor editorial changes. We have determined that these minor changes:

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

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

We also determined that these changes will not increase the economic burden on any operator or increase the scope of this final rule.

We reviewed Boeing Alert Service Bulletin 757-53A0101, dated November 8, 2016. The service information describes procedures for repetitive surface high frequency eddy current (HFEC) inspections for any cracking of the fuselage station (STA) 1380 frame inner chord; an identification of the material (an inspection or measurement) of the fuselage STA 1380 frame inner chord; and applicable corrective actions. 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.

We estimate that this AD affects 588 airplanes of U.S. registry. We estimate the following costs to comply with this AD:

We have received no definitive data that would enable us to provide cost estimates for the on-condition actions 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.

We are 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 is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes to the Director of the System Oversight Division.

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) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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 (AD):