2024-08105. Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-8 and 737-9 airplanes. This AD was prompted by a determination that the loss of a ground through the P6 panel results in the failure of the standby power control unit (SPCU). The loss of the SPCU and ground through the P6 panel could result in the loss of significant flightcrew instrumentation and displays. This AD requires installing two bonding jumpers from the P6 panel structure to primary structure. The FAA is issuing this AD to address the unsafe condition on these products.

DATES:

This AD is effective May 22, 2024.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of May 22, 2024.

ADDRESSES:

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2023-1400; 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 material that is incorporated by reference, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone [phone]; website myboeingfleet.com.

• You may view this material that is incorporated by reference 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-2023-1400.

FOR FURTHER INFORMATION CONTACT:

Raja Vengadasalam, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: [phone]; email: [e-mail].

SUPPLEMENTARY INFORMATION:

Background

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 737-8 and 737-9 airplanes. The NPRM published in the Federal Register on August 7, 2023 (88 FR 52055). The NPRM was prompted by a determination that the loss of a ground through the P6 panel results in the failure of the SPCU. In the NPRM, the FAA proposed to require installing two bonding jumpers from the P6 panel structure to primary structure. The FAA is issuing this AD to address loss of the SPCU function in combination with other lost P6 functions. The unsafe condition, if not addressed, could result in the loss of significant flightcrew instruments and displays, and may lead to loss of continued safe flight and landing.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from United Airlines, who supported the NPRM without change, Boeing, the Foundation for Aviation Safety, and three individuals.

Request for Change to Background Paragraph

Boeing requested that the FAA revise the description of the incident that prompted the NPRM. The Background section of the NPRM stated the following:

During a bonding analysis, it was determined that separate redundant ground paths from the two ground blocks on the SPCU tray to airplane primary structure are required in order to prevent a single point of failure condition, which could result in a potentially confusing combination of flight deck effects and a combination of lost functionality.

Boeing requested that this statement be clarified: (1) The single point of failure condition would result in the loss of SPCU function, and (2) the loss of SPCU function, in combination with other lost P6 functions, could result in a potentially confusing combination of flight deck effects and lost functionality. Boeing stated that the additional information would clarify and add detail to expand to other additional equipment in the P6.

The FAA agrees with the suggested revision. However, the Background section is not repeated in this final rule in its entirety. Therefore, the FAA has not changed this final rule.

The Foundation for Aviation Safety noted that the P6 panel provides circuit breakers for many of the airplane's most critical systems. The Foundation, and three individuals, requested that the FAA prohibit further operation of the 737 MAX.

The FAA has determined that the corrective action mandated by this AD will adequately address this unsafe condition. Therefore, the FAA has not changed this final rule in response to these comments.

Conclusion

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.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Boeing Alert Requirements Bulletin 737-24A1248 RB, dated May 16, 2022. This service information specifies procedures for installing new bonding jumpers from the P6 panel structure to the primary structure to provide a redundant ground path for the SPCU.

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 .

Costs of Compliance

The FAA estimates that this AD affects 79 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

Estimated costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Install two bonding jumpers	3 work-hours × $85 per hour = $255	$180	$435	$34,365

Authority for This Rulemaking

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.

Regulatory Findings

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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

The Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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. The FAA amends § 39.13 by adding the following new airworthiness directive:

2024-06-03 The Boeing Company: Amendment 39-22708; Docket No. FAA-2023-1400; Project Identifier AD-2022-01374-T.

(a) Effective Date

This airworthiness directive (AD) is effective May 22, 2024.

(b) Affected ADs

None.

(c) Applicability

This AD applies to The Boeing Company Model 737-8 and 737-9 airplanes, certificated in any category, as identified in Boeing Alert Requirements Bulletin 737-24A1248 RB, dated May 16, 2022.

(d) Subject

Air Transport Association (ATA) of America Code 24, Electrical Power.

(e) Unsafe Condition

This AD was prompted by a determination that separate redundant ground paths from the two ground blocks on the standby power control unit (SPCU) tray to airplane primary structure are required in order to prevent a single point of failure condition. The FAA is issuing this AD to address loss of the SPCU in combination with other lost P6 functions. The unsafe condition, if not addressed, could result in the loss of significant flightcrew instruments and displays, and may lead to loss of continued safe flight and landing.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Required Actions

Except as specified by paragraph (h) of this AD: At the applicable times specified in the “Compliance” paragraph of Boeing Alert Requirements Bulletin 737-24A1248 RB, dated May 16, 2022, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-24A1248 RB, dated May 16, 2022.

Note 1 to paragraph (g): Guidance for accomplishing the actions required by this AD can be found in Boeing Alert Service Bulletin 737-24A1248, dated May 16, 2022, which is referred to in Boeing Alert Requirements Bulletin 737-24A1248 RB, dated May 16, 2022.

(h) Exceptions to Service Information Specifications

Where the Compliance Time column of the table in the “Compliance” paragraph of Boeing Alert Requirements Bulletin 737-24A1248 RB, dated May 16, 2022, refers to the original issue date of Requirements Bulletin 737-24A1248 RB, this AD requires using the effective date of this AD.

(i) Alternative Methods of Compliance (AMOCs)

(1) The Manager, AIR-520 Continued Operational Safety Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or responsible Flight Standards Office, as appropriate. If sending information directly to the manager of the certification office, send it to the attention of the person identified in paragraph (j) of this AD. Information may be emailed to: [e-mail].

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office.

(3) An AMOC that provides an acceptable level of safety may be used for any repair, modification, or alteration required by this AD if it is approved by The Boeing Company Organization Designation Authorization (ODA) that has been authorized by the Manager, AIR-520 Continued Operational Safety Branch, FAA, to make those findings. To be approved, the repair method, modification deviation, or alteration deviation must meet the certification basis of the airplane, and the approval must specifically refer to this AD.

(j) Related Information

(1) For more information about this AD, contact Raja Vengadasalam, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: [phone]; email: [e-mail].

(2) Service information identified in this AD that is not incorporated by reference is available at the address specified in paragraph (k)(3) of this AD.

(k) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.

(i) Boeing Alert Requirements Bulletin 737-24A1248 RB, dated May 16, 2022.

(ii) [Reserved]

(3) For material that is incorporated by reference, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone [phone]; website myboeingfleet.com.

(4) You may view this material that is incorporated by reference 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.

(5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/[e-mail].

Issued on March 15, 2024.

Victor Wicklund,

Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.