2018-24944. Airworthiness Directives; Pratt & Whitney Division (PW) 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 certain Pratt & Whitney Division (PW) PW4158 turbofan engines. This proposed AD was prompted by several reports of high cycle fatigue (HCF) cracks found in the fuel nozzle supply manifold. This proposed AD would require replacement of the affected fuel nozzles and fuel nozzle manifold supply assemblies with parts eligible for installation. This proposed AD would also require installation of new brackets and clamps on the fuel supply manifold assemblies. We are proposing this AD to address the unsafe condition on these products.

DATES:

We must receive comments on this proposed AD by January 3, 2019.

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: [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 Pratt & Whitney, 400 Main Street, East Hartford, CT 06108; phone: [phone]; fax: [phone]. 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-2018-0924; 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 address for Docket Operations (phone: [phone]) is listed above. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Scott Hopper, Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: [phone]; fax: [phone]; email: [e-mail].

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-2018-0924; Product Identifier 2018-NE-34-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

We received several reports of HCF cracks found in the fuel nozzle supply manifold tube at the braze joint interface on PW PW4158 turbofan engines identified with suffix-3 on the Engine Data Plate, and equipped with the Talon IIB combustor chamber. The root cause of the cracks in the braze joint was attributed to thermal mechanical fatigue due to high thermal gradients on engines equipped with the Talon IIB combustor chamber. This condition, if not addressed, could result in engine fire, damage to the engine, and damage to the airplane.

Related Service Information Under 1 CFR Part 51

We reviewed PW Service Bulletin (SB) PW4ENG 73-224, dated November 8, 2017. The SB describes procedures for replacing the fuel nozzle supply manifold assemblies with parts eligible for installation, and installing new brackets and clamps on the fuel nozzle supply manifolds. 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 the ADDRESSES section.

Other Related Service Information

We reviewed PW SB PW4ENG 73-223, dated February 5, 2018. This SB describes procedures for replacing the fuel nozzles and fuel nozzle support assemblies with parts eligible for installation.

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 replacing the affected fuel nozzles and fuel nozzle manifold supply assemblies with parts eligible for installation. This proposed AD would also require installation of new brackets and clamps on the fuel supply manifold assemblies.

Costs of Compliance

We estimate that this proposed AD affects 114 engines installed on airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Remove and replace (24) fuel nozzles	48 work-hours × $85 per hour = $4,080	$423,471.12	$427,551.12	$48,740,827.68
Replace fuel supply manifold tubes and install new clamps and brackets	16 work-hours × $85 per hour = $1,360	77,158.97	78,518.97	8,951,162.58

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.

§ 39.13

[Amended]

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

Pratt & Whitney Division: Docket No. FAA-2018-0924; Product Identifier 2018-NE-34-AD.

(a) Comments Due Date

We must receive comments by January 3, 2019.

(b) Affected ADs

None.

(c) Applicability

This AD applies to Pratt & Whitney Division (PW) PW4158 turbofan engines designated by a -3 on the Engine Data Plate and with Talon II outer combustion chamber assembly, part number (P/N) 51J228, installed.

(d) Subject

Joint Aircraft System Component (JASC) Code 7310, Engine Fuel Distribution.

(e) Unsafe Condition

This AD was prompted by several reports of high cycle fatigue (HCF) cracks found in the fuel nozzle supply manifold tube at the braze joint interface. We are issuing this AD to prevent failure of the fuel nozzles. The unsafe condition, if not addressed, could result in engine fire, damage to the engine, and damage to the airplane.

(f) Compliance

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

(g) Required Actions

No later than, the next engine shop visit after the effective date of this AD, do the following:

(1) Remove the 24 fuel nozzles, part number (P/N) 51J344, and replace with P/N 51J397.

(2) Replace the fuel nozzle manifold supply assemblies and install new brackets and clamps on the fuel supply manifolds in accordance with the “For Engines Installed on Aircraft” or “For Engines Not Installed on Aircraft” sections, as applicable, of the Accomplishment Instructions in PW Service Bulletin (SB) PW4ENG 73-224, dated November 8, 2017.

(h) Definitions

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 case flanges, except for the following situations, which do not constitute an engine shop visit:

(1) Separation of engine flanges solely for the purposes of transportation of the engine without subsequent maintenance.

(2) Separation of engine flanges solely for the purposes of replacing the fan or propulsor without subsequent maintenance.

(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. 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 local flight standards district office/certificate holding district office.

(j) Related Information

(1) For more information about this AD, contact Scott Hopper, Aerospace Engineer, ECO Branch, FAA, Engine and Propeller Standards Branch, 1200 District Avenue, Burlington, MA 01803; phone: [phone]; fax: [phone]; email: [e-mail].

(2) For PW service information identified in this AD, contact Pratt & Whitney, 400 Main St., East Hartford, CT 06108; phone: [phone]; fax: [phone]. 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.

Issued in Burlington, Massachusetts, on November 9, 2018.

Karen M. Grant,

Acting Manager, Engine and Propeller Standards Branch, Aircraft Certification Service.