AD 2023-09-04

This AD is effective June 29, 2023.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of June 29, 2023.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2022-1410; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

Material Incorporated by Reference:

• 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; website 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 regulations.gov under Docket No. FAA-2022-1410.

Brandon Lucero, Aerospace Engineer, Cabin Safety and Environmental Systems Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3569; email: brandon.lucero@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 certain The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes, and certain Model 737-8 and -9 airplanes. The NPRM published in the Federal Register on November 30, 2022 (87 FR 73507). The NPRM was prompted by reports from Boeing of uncommanded escape slide deployments in the passenger compartment while the airplane was on the ground, caused by too much tension in the inflation cable (introduced during packing of the slide) and the movement of the escape slide assembly in the escape slide compartment during normal airplane operations. The escape slide is used in the door-mounted escape system of the forward and aft entry doors, and the forward and aft galley service doors on the affected airplanes. In the NPRM, the FAA proposed to require inspecting all escape slide assemblies to identify affected parts, and applicable on-condition actions. The FAA is issuing this AD to address inflation of the escape slide while it is in the escape slide compartment, which could result in injury to passengers and crew during normal operation, or impede an emergency evacuation by rendering the exit unusable.

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

The FAA received additional comments from Aviation Partners Boeing, AIRDO, Singapore Airlines (SIA), American Airlines (AAL), Southwest Airlines (SWA), and an individual. The following presents the comments received on the NPRM and the FAA's response to each comment.

Aviation Partners Boeing stated that the installation of winglets per Supplemental Type Certificate STC ST00830SE does not affect the accomplishment of the actions in the proposed AD.

The FAA agrees with the commenter that the installation of STC ST00830SE does not affect the ability to accomplish the actions required by this AD. The FAA has not changed this AD in this regard.

AIRDO, SIA, and SWA requested the proposed AD be revised to allow using maintenance records in lieu of inspecting the part number of the escape slide assembly as required by the service information specified in paragraph (g) of the proposed AD. SWA noted that escape slides are time limited parts and can easily be identified by a maintenance records review. AIRDO added that the escape slide is controlled by the operator's maintenance system, so it will be easier to use a maintenance record to identify the part number.

The FAA agrees to allow for a maintenance record review to determine the part number of the escape slide assembly, provided the part number can be conclusively determined from the records review. The FAA has added paragraph (h)(3) of this AD to allow a records review in lieu of an inspection.

AAL suggested adding a parts prohibition paragraph to the proposed AD. AAL noted that the proposed AD, Boeing Special Attention Requirements Bulletin 737-25-1855 RB, Revision 1, dated April 13, 2022, and Boeing Special Attention Requirements Bulletin 737-25-1866 RB, Revision 1, dated April 11, 2022, do not explicitly prohibit the installation of slide P/N 5A3307-7 after the actions have been accomplished. AAL requested that the FAA add a paragraph prohibiting the installation of an escape slide part number (P/N) 5A3307-7 after the actions in paragraph (g) of the proposed AD have been accomplished.

The FAA agrees to clarify. 14 CFR 39.7 specifies that once an AD is issued, no person may operate a product to which the AD applies except in accordance with the requirements of that AD. Further, 14 CFR 39.9 imposes a continuing obligation to maintain compliance with an AD by establishing a separate violation for each time an aircraft is operated that fails to meet AD requirements. Thus, operators have an ongoing obligation to ensure that the AD-mandated configuration is maintained. The FAA has not changed this AD as a result of the request.

SIA requested Boeing Information Notice 737-25-1855 IN 01, dated April 22, 2022, to be referenced along with Boeing Special Attention Requirements Bulletin 737-25-1855 RB, Revision 1, dated April 13, 2022. SIA noted that Boeing Information Notice 737-25-1855 IN 01, dated April 22, 2022, changed the weight and balance information to “none.”

The FAA disagrees with the commenter's request. The weight and balance information is only contained in Boeing Special Attention Service Bulletin 737-25-1855, Revision 1, dated April 13, 2022, and is not required for compliance with this AD. Additionally, the information in Boeing Information Notice 737-25-1855 IN 01, dated April 22, 2022, is not necessary to address the unsafe condition or comply with this AD. The FAA has not changed this AD regarding this issue.

An individual requested the FAA require inspecting other aircraft of similar type design. The individual expressed concern that an emergency evacuation would render the exit unusable.

The FAA agrees to clarify. An emergency evacuation slide is often designed for a particular aircraft. In this case, the escape slide assembly in question is a unique installation to the 737, and the same design does not exist on other aircraft. Therefore, no change to this AD is necessary.

The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, and any other changes described previously, 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 Special Attention Requirements Bulletin 737-25-1855 RB, Revision 1, dated April 13, 2022, and Boeing Special Attention Requirements Bulletin 737-25-1866 RB, Revision 1, dated April 11, 2022. This service information specifies procedures for inspecting all escape slide assemblies to identify affected parts, and applicable on-condition actions. The on-condition actions include replacing any escape slide assembly having part number (P/N) 5A3307-7 with a new assembly having P/N 5A3307-9 or P/N 5A3307-701 (an escape slide assembly having P/N 5A3307-701 is one on which a firing cable retention modification has been done and the assembly has been reidentified). These documents are distinct since they apply to different airplane models.

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 2,502 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 replacements that would be required based on the results of the inspection. The agency has no way of determining the number of aircraft that might need these replacements:

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: