87 FR 118 pgs. 36781-36783 - Airworthiness Directives; General Electric Company Turboshaft Engines
Type: PRORULEVolume: 87Number: 118Pages: 36781 - 36783
Pages: 36781, 36782, 36783Docket number: [Docket No. FAA-2022-0690; Project Identifier AD-2021-01360-E]
FR document: [FR Doc. 2022-13154 Filed 6-17-22; 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-2022-0690; Project Identifier AD-2021-01360-E]
RIN 2120-AA64
Airworthiness Directives; General Electric Company Turboshaft 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 all General Electric Company (GE) CT7-8A model turboshaft engines. This proposed AD was prompted by the manufacturer revising the airworthiness limitations section (ALS) of the existing engine maintenance manual (EMM) to incorporate reduced life limits for certain stage 1 turbine aft cooling plates, stage 2 turbine forward cooling plates, turbine interstage seals, and stage 4 turbine disks. This proposed AD would require revising the ALS of the existing EMM and the operator's existing approved maintenance or inspection program, as applicable, to incorporate reduced life limits for these parts. 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 August 5, 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 https://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@ae.ge.com; website: https://www.ge.com. You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 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
You may examine the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2022-0690; 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.
FOR FURTHER INFORMATION CONTACT:
Sungmo Cho, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: (781) 238-7241; email: Sungmo.D.Cho@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-2022-0690; Project Identifier AD-2021-01360-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 https://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
[top] 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
Background
The FAA was notified that the manufacturer revised the ALS of the existing EMM to incorporate reduced life limits for certain stage 1 turbine aft cooling plates, stage 2 turbine forward cooling plates, turbine interstage seals, and stage 4 turbine disks (life-limited parts) installed on CT7-8A model turboshaft engines. Additionally, the manufacturer published service information that introduced the reduced life limits. The life limits were reduced by the manufacturer as the result of an analysis of the life management models for these parts. This condition, if not addressed, could result in uncontained part release, damage to the engine, damage to the helicopter, and possible loss of control of the helicopter.
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 CT7-8 Service Bulletin 72-0062, Revision 01, dated December 22, 2021. This service information provides the reduced life limits for certain life-limited parts.
Proposed AD Requirements in This NPRM
This proposed AD would require revising the ALS of the applicable GE CT7-8 EMM and the operator's existing approved maintenance or inspection program, as applicable, to incorporate reduced life limits for certain life-limited parts.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 126 engines installed on helicopters 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 |
|---|---|---|---|---|
| Revise ALS of EMM and the operator's existing approved maintenance or inspection program | 1 work-hour × $85 per hour = $85 | $0 | $85 | $10,710 |
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.
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-2022-0690; Project Identifier AD-2021-01360-E.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive (AD) by August 5, 2022.
(b) Affected ADs
None.
(c) Applicability
This AD applies to General Electric Company CT7-8A model turboshaft engines.
(d) Subject
Joint Aircraft System Component (JASC) Code 7240, Turbine Engine Combustion Section; 7250, Turbine Section.
(e) Unsafe Condition
This AD was prompted by the manufacturer revising the airworthiness limitations section (ALS) of the existing engine maintenance manual (EMM) to incorporate reduced life limits for certain stage 1 turbine aft cooling plates, stage 2 turbine forward cooling plates, turbine interstage seals, and stage 4 turbine disks. The FAA is issuing this AD to prevent failure of the stage 1 turbine aft cooling plates, stage 2 turbine forward cooling plates, turbine interstage seals, and stage 4 turbine disks. The unsafe condition, if not addressed, could result in uncontained part release, damage to the engine, damage to the helicopter, and possible loss of control of the helicopter.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Required Actions
(1) Within 90 days after the effective date of this AD, revise the ALS of the existing GE CT7-8 Turboshaft EMM and the operator's existing approved maintenance or inspection program, as applicable, by incorporating the following reduced life limits:
[top] (i) For stage 1 turbine aft cooling plate, part number (P/N) 6064T09P02, change the life
(ii) For stage 2 turbine forward cooling plate, P/N 4106T80P01, change the life limit cycles from 8,000 CSN to 7,200 CSN;
(iii) For turbine interstage seal, P/N 4111T86P03, change the life limit cycles from 29,200 CSN to 19,000 CSN; and
(iv) For stage 4 turbine disk, P/N 6068T32P04, change the life limit cycles from 24,100 CSN to 12,100 CSN.
(2) After performing the actions required by paragraph (g)(1) of this AD, except as provided in paragraph (h) of this AD, no alternative life limits may be approved.
(h) 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 (i) 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.
(i) Related Information
For more information about this AD, contact Sungmo Cho, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: (781) 238-7241; email: Sungmo.D.Cho@faa.gov.
Issued on June 14, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft Certification Service.
[FR Doc. 2022-13154 Filed 6-17-22; 8:45 am]
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