Proposed Rule
Airworthiness Directives; The Boeing Company Airplanes
The full text was pulled automatically from the official source and is not Threadline News reporting; the annotations alongside it are.
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 787-8, 787-9, and 787-10 airplanes. This proposed AD was prompted by a report indicating that the protection system on the left fan cowl of the right engine does not sufficiently cover the components and systems from possible cross engine debris. This proposed AD would require performing a maintenance records check or inspection of the right engine to determine the part number of the left fan cowl 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 September 21, 2026.
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: 202-493-2251. 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. AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2026-7233; 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. Material Incorporated by Reference: For Boeing material identified in this proposed AD, 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 material 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-2026-7233.
For further information contact
Shaan S. Brar, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206- 231-3558; email: [email protected].
Supplementary information
Comments Invited
The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments using a method listed under the ADDRESSES section. Include "Docket No. FAA-2026-7233; Project Identifier AD-2026-00062-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 Shaan S. Brar, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3558; email: [email protected]. 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 a report from the manufacturer indicating that the protection system on the left fan cowl of the right engine does not sufficiently cover the components and systems for airplanes equipped with Rolls Royce Deutschland Ltd & Co KG (RRD) Model Trent 1000-AE3, 1000-CE3, 1000-D3, 1000-G3, 1000-H3, 1000-J3, and 1000-K3 engines. This insufficient cover could leave multiple oil lines and the P30 sense line in the right engine exposed to possible cross engine debris from the intermediate pressure turbine (IPT) rotor stage of the left engine. This condition, if not addressed, could lead to damage to critical systems in the right engine due to debris from the left engine during an uncontained engine failure event, resulting in an in-flight dual engine shutdown of the airplane.
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.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Boeing Special Attention Requirements Bulletin B787-81205-SB540022-00 RB, Issue 001, dated February 19, 2026. This material specifies procedures for performing a maintenance records check or inspection of the right engine, left fan cowl for fan cowl part numbers 725Z2300-307, 725Z2300-305, or 725Z2300-5003, and applicable on-condition actions. On-condition actions include modifying or replacing the existing right engine left fan cowl. This material 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.
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified in the material 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 material at regulations.gov under Docket No. FAA-2026-7233.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 22 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:
Estimated Costs
Cost per Cost on U.S. Action Labor cost Parts cost product operators
Maintenance records check or 3 work-hours x $85 per $0 $255 $5,610 inspection. hour = $255.
The FAA estimates the following costs to do any necessary modifications or replacements 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 this modification or replacement:
On-Condition Costs