Airworthiness Directives: Pratt and Whitney Division Engines

Airworthiness Directives; Pratt & Whitney Division Engines

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-2026-4643; Project Identifier AD-2025-01612-E" 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 revise 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 Molly Sturgis, 2200 South 216th Street, Des Moines, WA 98198. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

The FAA was notified of multiple events involving PW PW4000-94 engines in which tailpipe fire, loss of thrust control, or engine in-flight shutdown occurred. A manufacturer investigation revealed that these events were caused by undetected deterioration of Pb sensors due to epoxy deterioration, which can lead to erroneous Pb sensor measurements and incorrect fuel commands. This condition, if not addressed, could result in engine fire, loss of thrust control, and engine in-flight shutdown.

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.

Proposed AD Requirements in This NPRM

This proposed AD would require replacing Pb sensors within certain compliance times.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 210 engines installed on airplanes of U.S. registry.

The FAA estimates the following costs to comply with this proposed AD:

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.

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

Pratt & Whitney Division: Docket No. FAA-2026-4643; Project Identifier AD-2025-01612-E.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by July 10, 2026.

(b) Affected ADs

None.

(c) Applicability

This AD applies to all Pratt & Whitney Division (PW) Model PW4052, PW4056, PW4060, PW4060A, PW4060C, PW4062, PW4062A, PW4152, PW4156, PW4156A, PW4158, PW4460, and PW4462 engines.

(d) Subject

Joint Aircraft System Component (JASC) Code 7300, Engine Fuel and Control.

(e) Unsafe Condition

This AD was prompted by multiple reports of tailpipe fire, loss of thrust control, and engine in-flight shutdown due to undetected deterioration of pressure burner (Pb) sensors. The FAA is issuing this AD to detect and correct the deterioration of Pb sensors. The unsafe condition, if not addressed, could result in engine fire, loss of thrust control, and engine in-flight shutdown.

(f) Compliance

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

(g) Definitions

For the purpose of this AD, a "part eligible for installation" is a Pb sensor that has accumulated less than 30,000 flight hours (FH) since new or since repair and less than 10 years in service since new or since repair.

(h) Required Actions

(1) Replace the Pb sensor within the electronic engine control (EEC) with a part eligible for installation within the applicable number of months after the effective date of this AD, as specified in table 1 to paragraph (h) of this AD, and thereafter before accumulating 30,000 FH since new or since repair, or before accumulating 10 years in service, whichever occurs first.

(2) For Pb sensors that have accumulated less than 30,000 FH since new or since repair and less than 10 years in service since new or since repair as of the effective date of this AD, replace the Pb sensor within the EEC with a part eligible for installation as follows, whichever occurs later:

(i) Before accumulating 30,000 FH or 10 years in service since new or since repair as applicable, whichever occurs first.

(ii) Within 30 months after the effective date of this AD.

Note 1 to paragraph (h): Guidance for determining the age of Pb sensors may be found in PW Service Bulletin PW4ENG 73-221, Revision No. 3, dated July 1, 2024.

(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 local Flight Standards District Office, as appropriate. If sending information directly to the manager of the AIR-520 Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (j) of this AD and email to: [email protected].

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.

(j) Additional Information

(1) For more information about this AD, contact Molly Sturgis, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (562) 627-5373; email: [email protected].

(2) For material identified in this AD that is not incorporated by reference, contact PW, 400 Main Street, East Hartford, CT 06118; phone: (800) 565-0140; email: [email protected]; website: connect.prattwhitney.com.

(k) Material Incorporated by Reference

None.

[FR Doc. 2026-10408 Filed 5-22-26; 8:45 am]

BILLING CODE 4910-13-P