2022-21398. Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-8 and 737-9 airplanes, and certain Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This proposed AD was prompted by reports of damage to the auxiliary power unit (APU) fuel line shroud located in the aft cargo area; investigation revealed that the placement of the pressure switch wire clamp assembly and its fastener allowed interference of the fastener against the APU fuel line shroud. This proposed AD would require inspecting the APU fuel line shroud for damage, inspecting the pressure switch wire clamp for correct bolt orientation and horizontal distance from the APU fuel line shroud, and applicable on-condition actions. The FAA is proposing this AD to address the unsafe condition on these products.

DATES:

The FAA must receive comments on this proposed AD by November 21, 2022.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.

• Fax: [phone].

• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone [phone]; internet myboeingfleet.com. You may view this referenced 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 by searching for and locating Docket No. FAA-2022-1068.

Examining the AD Docket

You may examine the AD docket at regulations.gov by searching for and locating Docket No. FAA-2022-1068; 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 NPRM, any comments received, and other information. The street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT:

Chris Baker, Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone: [phone]; email: [e-mail].

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under ADDRESSES . Include “Docket No. FAA-2022-1068; Project Identifier AD-2022-00358-T” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments.

Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM.

Confidential Business Information

CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Chris Baker, Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone: [phone]; email: [e-mail]. Any commentary that the FAA receives that is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

The FAA has received reports of damage to the APU fuel line shroud located in the aft cargo area of certain models of the subject airplanes. FAA and manufacturer investigation revealed that the placement of the pressure switch wire clamp assembly and its fastener allowed interference of the fastener against the APU fuel line shroud. This condition, if not addressed, could result in a damaged APU fuel line shroud and consequent failure of the APU fuel hose, which could result in a flammable fluid leak in an ignition zone.

FAA's Determination

The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Boeing Alert Requirements Bulletins 737-38A1072 RB and 737-38A1073 RB, both dated February 25, 2022. This service information specifies procedures for a general visual inspection of the APU fuel line shroud in the area within 3 inches of the fastener of the pressure switch wire clamp for any damage (any crack or hole, any damage that exposes bare metal on the APU fuel line shroud, and any dent damage found that decreases the outside diameter of the shroud by more than 0.031 inch); a detailed inspection of the pressure switch wire clamp to determine if the fastener of the pressure switch wire clamp is installed with the bolt head on top and the nut on the bottom, and that there is a minimum 1.5 inches of horizontal separation between the fastener of the pressure switch wire clamp and the APU fuel line shroud, and applicable on-condition actions. On-condition actions include replacing the existing APU fuel line shroud with a new or repaired shroud; repairing any damage to the APU fuel line shroud; re-installing the fastener of the pressure switch wire clamp with the bolt head on top and the nut on the bottom; and re-installing the pressure switch wire clamp assembly to make sure there is 1.5 inches minimum of horizontal separation between the fastener of the pressure switch wire clamp and the APU fuel line shroud. 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 .

Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified in the service information already described, except for any differences identified as exceptions in the regulatory text of this proposed AD. For information on the procedures and compliance times, see this service information at regulations.gov by searching for and locating Docket No. FAA-2022-1068.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 1,919 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
One-time Inspections	2 work-hours × $85 per hour = $170	$0	$170	$326,230

The FAA estimates the following costs to do any necessary repairs, replacements, or re-installations that would be required based on the results of the proposed inspection. The agency has no way of determining the number of aircraft that might need these repairs, replacements, or re-installations:

On-Condition Costs

Action	Labor cost	Parts cost	Cost per product
Repair	Up to 3 work-hours × $85 per hour = Up to $255	$0	Up to $255.
Replacement (includes re-installation)	Up to 300 work-hours × $85 per hour = Up to $25,500	Up to $8,158	Up to $33,658.

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some or all of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected operators.

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

The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 this proposed regulation:

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

(2) Would not affect intrastate aviation in Alaska, and

(3) Would 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 Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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:

The Boeing Company: Docket No. FAA-2022-1068; Project Identifier AD-2022-00358-T.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by November 21, 2022.

(b) Affected ADs

None.

(c) Applicability

This AD applies to The Boeing Company airplanes identified in paragraphs (c)(1) and (2) of this AD, certificated in any category.

(1) Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes, as identified in Boeing Alert Requirements Bulletin 737-38A1072 RB, dated February 25, 2022.

(2) Model 737-8 and 737-9 airplanes, as identified in Boeing Alert Requirements Bulletin 737-38A1073 RB, dated February 25, 2022.

(d) Subject

Air Transport Association (ATA) of America Code 28, Fuel.

(e) Unsafe Condition

This AD was prompted by reports of damage to the auxiliary power unit (APU) fuel line shroud located in the aft cargo area; investigation revealed that the placement of the pressure switch wire clamp assembly and the fastener allowed interference of the fastener against the APU fuel line shroud. The FAA is issuing this AD to address interference of the fastener against the APU fuel line shroud, possibly resulting in a damaged APU fuel line shroud and consequent failure of the APU fuel hose, which could result in a flammable fluid leak in an ignition zone.

(f) Compliance

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

(g) Required Actions

(1) For the airplanes identified in paragraph (c)(1) of this AD, except as specified by paragraph (h) of this AD: At the applicable times specified in the “Compliance” paragraph of Boeing Alert Requirements Bulletin 737-38A1072 RB, dated February 25, 2022, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-38A1072 RB, dated February 25, 2022.

Note 1 to paragraph (g)(1): Guidance for accomplishing the actions required by this AD can be found in Boeing Alert Service Bulletin 737-38A1072, dated February 25, 2022, which is referred to in Boeing Alert Requirements Bulletin 737-38A1072 RB, dated February 25, 2022.

(2) For the airplanes identified in paragraph (c)(2) of this AD, except as specified by paragraph (h) of this AD: At the applicable times specified in the “Compliance” paragraph of Boeing Alert Requirements Bulletin 737-38A1073 RB, dated February 25, 2022, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-38A1073 RB, dated February 25, 2022.

Note 2 to paragraph (g)(2): Guidance for accomplishing the actions required by this AD can be found in Boeing Alert Service Bulletin 737-38A1073, dated February 25, 2022, which is referred to in Boeing Alert Requirements Bulletin 737-38A1073 RB, dated February 25, 2022.

(h) Exceptions to Service Information Specifications

(1) Where the Compliance Time columns of the tables in the “Compliance” paragraphs of Boeing Alert Requirements Bulletin 737-38A1072 RB, dated February 25, 2022, use the phrase “the original issue date of Requirements Bulletin 737-38A1072 RB,” this AD requires using “the effective date of this AD.”

(2) Where the Compliance Time columns of the tables in the “Compliance” paragraphs of Boeing Alert Requirements Bulletin 737-38A1073 RB, dated February 25, 2022, use the phrase “the original issue date of Requirements Bulletin 737-38A1073 RB,” this AD requires using “the effective date of this AD.”

(i) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Seattle ACO 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)(1) 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, Seattle ACO 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 Chris Baker, Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone: [phone]; email: [e-mail].

(2) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone [phone]; internet myboeingfleet.com. You may view this referenced 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.

Issued on August 30, 2022.

Christina Underwood,

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