Airworthiness Directives; General Electric Company Turboshaft Engines

[Federal Register Volume 87, Number 170 (Friday, September 2, 2022)]
[Rules and Regulations]
[Pages 54130-54131]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-18961]



[[Page 54130]]

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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; 
Amendment 39-22167; AD 2022-18-16]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Turboshaft 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
General Electric Company (GE) CT7-8A model turboshaft engines. 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. This AD requires 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 issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective October 7, 2022.

ADDRESSES: AD Docket: You may examine the AD docket at 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 final rule, any 
comments received, and other information. The address for Docket 
Operations is U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue 
SE, Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Sungmo Cho, Aviation Safety Engineer, 
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 
(781) 238-7241; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to all GE CT7-8A model 
turboshaft engines. The NPRM published in the Federal Register on June 
21, 2022 (87 FR 36781). The NPRM was prompted by the manufacturer 
revising 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. In the NPRM, the FAA proposed to 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. The FAA is issuing 
this AD to address the unsafe condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received one comment, from Air Line Pilots Association, 
International (ALPA). ALPA supported the NPRM without change.

Conclusion

    The FAA reviewed the relevant data, considered the comment 
received, and determined that air safety requires adopting the AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes, this 
AD is adopted as proposed in the NPRM.

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.

Costs of Compliance

    The FAA estimates that this AD affects 126 engines installed on 
helicopters of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Revise ALS of EMM and the operator's    1 work-hour x $85 per                 $0             $85         $10,710
 existing approved maintenance or        hour = $85.
 inspection program.
----------------------------------------------------------------------------------------------------------------

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

    This AD will not have federalism implications under Executive Order 
13132. This AD will 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 that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities

[[Page 54131]]

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 Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2022-18-16 General Electric Company: Amendment 39-22167; Docket No. 
FAA-2022-0690; Project Identifier AD-2021-01360-E.

(a) Effective Date

    This airworthiness directive (AD) is effective October 7, 2022.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) 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:
    (i) For stage 1 turbine aft cooling plate, part number (P/N) 
6064T09P02, change the life limit cycles from 6,600 cycles since new 
(CSN) to 4,900 CSN;
    (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: [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.

(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: [email protected].

(j) Material Incorporated by Reference

    None.

    Issued on August 29, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2022-18961 Filed 9-1-22; 8:45 am]
BILLING CODE 4910-13-P

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