DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2022-0690; Project Identifier AD-2021-01360-E]
Airworthiness Directives; General Electric Company Turboshaft
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to adopt a new airworthiness directive
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
ADDRESSES: You may send comments, using the procedures found in
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
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: firstname.lastname@example.org; 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.
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
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 Sungmo Cho, 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.
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.
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:
|Revise ALS of EMM and the operator's
existing approved maintenance or inspection program
x $85 per hour
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.
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
(1) Is not a ``significant regulatory action'' under Executive
(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
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.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness