87 FR 146 pgs. 46906-46908 - Airworthiness Directives; General Electric Company Turbofan Engines
Type: PRORULEVolume: 87Number: 146Pages: 46906 - 46908
Pages: 46906, 46907, 46908Docket number: [Docket No. FAA-2022-0977; Project Identifier AD-2022-00419-E]
FR document: [FR Doc. 2022-16011 Filed 7-29-22; 8:45 am]
Agency: Transportation Department
Sub Agency: Federal Aviation Administration
Official PDF Version: PDF Version
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2022-0977; Project Identifier AD-2022-00419-E]
RIN 2120-AA64
Airworthiness Directives; General Electric Company Turbofan Engines
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 General Electric Company (GE) CF34-8C and CF34-8E model turbofan engines. This proposed AD was prompted by a report of a crack found on the low-pressure turbine (LPT) stage 5 disk at the forward arm area. This proposed AD would require the removal of the affected LPT stage 5 disk and replacement with a part eligible for installation. 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 15, 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 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 General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 552-3272; email: aviation.fleetsupport@ge.com; website: www.ge.com. You may view this service information at the Airworthiness Products Section, Operational Safety Branch, FAA, 1200 District Avenue, Burlington, MA 01803. For information on the availability of this material at the FAA, call (817) 222-5110.
Examining the AD Docket
[top] You may examine the AD docket at www.regulations.gov by searching for
FOR FURTHER INFORMATION CONTACT:
Scott Stevenson, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: (781) 238-7132; email: Scott.M.Stevenson@faa.gov .
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-2022-0977; Project Identifier AD-2022-00419-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 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 www.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 Scott Stevenson, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803. 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 received a report of a crack found on an LPT stage 5 disk at the forward arm area. The manufacturer's analysis revealed that the crack was due to high-vibratory stress caused by a bladed disk mode that resulted in the initiation of multiple high cycle fatigue (HCF) cracks that connected, resulting in a long circumferential crack. As a result of its analysis, the manufacturer published service information that specifies procedures for the removal of the affected LPT stage 5 disk, part number (P/N) 4117T14P02, and replacement with an LPT stage 5 disk, P/N 4117T14P03. The replacement LPT stage 5 disk, P/N 4117T14P03, has a modified geometry (thicker forward arm) that will improve the HCF capability and reduce the likelihood of a crack. This condition, if not addressed, could result in failure of the LPT stage 5 disk, loss of engine thrust control, and reduced control 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.
Related Service Information
The FAA reviewed GE CF34-8C Service Bulletin (SB) 72-0352 R00, dated September 20, 2021, and GE CF34-8E SB 72-0240 R00, dated September 20, 2021. These SBs, differentiated by engine model, describe procedures for removing and replacing the affected LPT stage 5 disk, P/N 4117T14P02, with a new LPT stage 5 disk, P/N 4117T14P03.
Proposed AD Requirements in This NPRM
This proposed AD would require the removal of the affected LPT stage 5 disk and replacement with a part eligible for installation.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 112 engines installed on airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed AD:
| Action | Labor cost | Parts cost | Cost per product | Cost on U.S. operators |
|---|---|---|---|---|
| Remove and replace the LPT stage 5 disk | 2 work-hours × $85 per hour = $170 | $30,500 (pro-rated) | $30,670 | $3,435,040 |
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,
[top] (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:
General Electric Company: Docket No. FAA-2022-0977; Project Identifier AD-2022-00419-E.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive (AD) by September 15, 2022.
(b) Affected ADs
None.
(c) Applicability
This AD applies to General Electric Company CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5A2, CF34-8C5A3, CF34-8C5B1, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 model turbofan engines with an installed low-pressure turbine (LPT) stage 5 disk, part number (P/N) 4117T14P02.
(d) Subject
Joint Aircraft System Component (JASC) Code 7250, Turbine Section.
(e) Unsafe Condition
This AD was prompted by a report of a crack found on the LPT stage 5 disk at the forward arm area. The FAA is issuing this AD to prevent failure of the LPT stage 5 disk. The unsafe condition, if not addressed, could result in loss of engine thrust control and reduced control of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Required Actions
During the next piece-part exposure after the affected LPT stage 5 disk accumulates 8,000 cycles since new (CSN), remove the affected LPT stage 5 disk and replace with a part eligible for installation.
(h) Installation Prohibition
Do not install an affected LPT stage 5 disk with 8,000 CSN or more into the LPT module of the engine.
(i) Definitions
(1) For the purpose of this AD, a "part eligible for installation" is an LPT stage 5 disk, P/N 4117T14P03, or later approved P/N.
(2) For the purpose of this AD, "piece-part exposure" is when the LPT module is separated from the engine and the LPT stage 5 blades are removed from the LPT stage 5 disk.
(j) 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 (k) of this AD and email 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.
(k) Related Information
For more information about this AD, contact Scott Stevenson, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: (781) 238-7132; email: Scott.M.Stevenson@faa.gov .
Issued on July 21, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft Certification Service.
[FR Doc. 2022-16011 Filed 7-29-22; 8:45 am]
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