Airworthiness Directives; International Aero Engines (IAE) Turbofan engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for all International Aero Engines (IAE) PW1133G-JM, PW1133GA-JM, PW1130G-JM, PW1127G-JM, PW1127GA-JM, PW1127G1-JM, PW1124G-JM, PW1124G1-JM, and PW1122G-JM turbofan engines. This proposed AD was prompted by reports of in-flight engine shutdowns and aborted take-offs as the result of certain parts affecting the durability of the rear high-pressure compressor (HPC) rotor hub knife edge seal. This proposed AD would require replacing the diffuser case air seal assembly, the high-pressure turbine (HPT) 2nd-stage vane assembly, and the HPT 2nd-stage borescope stator vane assembly with parts eligible for installation. We are proposing this AD to address the unsafe condition on these products.

DATES:

We must receive comments on this proposed AD by July 26, 2018.

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 http://www.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.

For service information identified in this NPRM, contact International Aero Engines, 400 Main Street, East Hartford, CT 06118; phone: 800-565-0140; email: help24@pw.utc.com; internet: http://fleetcare.pw.utc.com. You may view this service information at the FAA, Engine and Propeller Standards Branch, 1200 District Avenue, Burlington, MA 01803. For information on the availability of this material at the FAA, call 781-238-7759.

Examining the AD Docket

You may examine the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2018-0404; 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, the regulatory evaluation, any comments received, and other information. The street address for Docket Operations (phone: 800-647-5527) is listed above. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Kevin M. Clark, Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-238-7088; fax: 781-238-7199; email: kevin.m.clark@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2018-0404; Product Identifier 2018-NE-15-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this NPRM. We will consider all comments received by the closing date and may amend this NPRM because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this NPRM.

Discussion

In-flight engine shutdowns and aborted take-offs have occurred on certain IAE turbofan engines as the result of a failed knife edge seal on engine serial numbers (ESNs) P770450 through P770614. In response to these events, the European Aviation Safety Agency published AD 2018-0041R1, dated March 23, 2018 (corrected on April 4, 2018). Additionally, the FAA published AD 2018-04-01 (83 FR 6791, February 15, 2018), for all Airbus Model A320-271N, A321-271N, and A321-272N airplanes. Both ADs describe procedures to de-pair affected airplanes and to discontinue extended operations (ETOPS) for airplanes with at least one affected engine.

An analysis by the manufacturer of these engine failures has shown that production modifications to the diffuser case air seal assembly and the 2nd-stage HPT vane assemblies, beginning with ESN P770450, negatively affected the durability of the rear HPC rotor hub knife edge seal. The modifications caused the knife edge seal on the rear HPC rotor hub to experience high-cycle fatigue and failure. This condition, if not addressed, could result in failure of one or more engines, loss of thrust control, and loss of the airplane.

Related Service Information

We reviewed Pratt & Whitney Alert Service Bulletin (ASB) PW1000G-C-72-00-0099-00A-930A-D, Issue No. 002, dated March 15, 2018. The ASB describes procedures for removing production modifications to the diffuser case air seal assembly, HPT 2nd-stage vane assembly, and the HPT 2nd-stage borescope stator vane assembly, beginning with ESN P770450, which resulted in an unanticipated increase in stress at the rear HPC rotor hub knife edge seal.

FAA's Determination

We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

Proposed AD Requirements

This proposed AD would require removing from service and replacing the diffuser case air seal assembly, P/N 30G4993-01; the HPT 2nd-stage vane assembly, P/N 30G7572; and the HPT 2nd-stage borescope stator vane assembly, P/N 30G7672, with parts eligible for installation.

Interim Action

We consider this proposed AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, we might consider additional rulemaking.

Costs of Compliance

We estimate that this proposed AD affects 16 engines installed on airplanes of U.S. registry.

We estimate 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.

We are 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 is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to engines, propellers, and associated appliances to the Manager, Engine and Propeller Standards Branch, Policy and Innovation Division.

Regulatory Findings

We 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) Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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 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.

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

International Aero Engines: Docket No. FAA-2018-0404; Product Identifier 2018-NE-15-AD.

(a) Comments Due Date

We must receive comments by July 26, 2018.

(b) Affected ADs

None.

(c) Applicability

This AD applies to International Aero Engines (IAE) PW1133G-JM, PW1133GA-JM, PW1130G-JM, PW1127G-JM, PW1127GA-JM, PW1127G1-JM, PW1124G-JM, PW1124G1-JM, and PW1122G-JM turbofan engines with engine serial numbers (ESNs) P770450 through P770614.

(d) Subject

Joint Aircraft System Component (JASC) Code 7230, Turbine Engine Compressor Section.

(e) Unsafe Condition

This AD was prompted by reports of in-flight engine shutdowns and aborted take-offs that were the result of a failed knife edge seal on ESNs P770450 through P770614. We are issuing this AD to prevent failure of the rear high-pressure compressor rotor hub knife edge seal. The unsafe condition, if not addressed, could result in failure of one or more engines, loss of thrust control, and loss of the airplane.

(f) Compliance

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

(g) Required Actions

At the next engine shop visit after the effective date of this AD, do the following:

(1) Remove from service the diffuser case air seal assembly, part number (P/N) 30G4993-01, and replace with a part eligible for installation.

(2) Remove from service the high-pressure turbine (HPT) 2nd-stage vane assembly, P/N 30G7572, and replace with a part eligible for installation.

(3) Remove from service HPT 2nd-stage borescope stator vane assembly, P/N 30G7672, and replace with a part eligible for installation.

(h) Definition

For the purpose of this AD, an “engine shop visit” is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges (lettered flanges). The separation of engine flanges solely for the purpose of transportation of the engine without subsequent engine maintenance does not constitute an engine shop visit.

(i) Alternative Methods of Compliance (AMOCs)

(1) The Manager, ECO 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 certification office, send it to the attention of the person identified in paragraph (j)(1) of this AD. You may email your request to: ANE-AD-AMOC@faa.gov.

(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) Related Information

(1) For more information about this AD, contact Kevin M. Clark, Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-238-7088; fax: 781-238-7199; email: kevin.m.clark@faa.gov.

(2) For service information identified in this AD, contact International Aero Engines, 400 Main Street, East Hartford, CT 06118; phone: 800-565-0140; email: help24@pw.utc.com; internet: http://fleetcare.pw.utc.com. You may view this referenced service information at the FAA, Engine and Propeller Standards Branch, 1200 District Avenue, Burlington, MA 01803. For information on the availability of this material at the FAA, call 781-238-7759.