DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2022-1314; Project Identifier AD-2021-00811-E;
Amendment 39-22579; AD 2023-21-07]
Airworthiness Directives; General Electric Company Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2018-03-13
for certain General Electric Company (GE) Model CT7-5A2, CT7-5A3, CT7-
7A, CT7-7A1, CT7-9B, CT7-9B1, CT7-9B2, CT7-9C, and CT7-9C3 engines. AD
2018-03-13 required initial and repetitive visual inspections and
fluorescent penetrant inspections (FPIs) of the main propeller shaft.
This AD was prompted by an in-flight failure of a main propeller shaft
on a GE Model CT7-9B engine, resulting in the loss of the propeller.
This AD requires initial and repetitive visual inspections, FPIs, and
ultrasonic inspections (USIs) of the main propeller shaft. Depending on
the results of these inspections, this AD requires replacement of the
main propeller shaft. As an optional terminating action to these
inspections, this AD requires revising the airworthiness limitations
section (ALS) of the existing maintenance manual (MM) and the
operator's existing approved maintenance program or inspection program,
as applicable, to incorporate incorporating the tasks and reduced
inspection thresholds for the main propeller shaft. The FAA is issuing
this AD to address the unsafe condition on these products.
DATES: This AD is effective December 11, 2023.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of December 11,
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2022-1314; 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.
Material Incorporated by Reference:
For GE service information identified in this final rule,
contact General Electric Company, 1 Neumann Way, Cincinnati, OH 45215;
phone: (513) 552-3272; email: firstname.lastname@example.org; website:
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. It is
also available at regulations.gov under Docket No. FAA-2022-1314.
FOR FURTHER INFORMATION CONTACT: Sungmo Cho, Aviation Safety Engineer,
FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (781) 238-
7241; email: Sungmo.D.Cho@faa.gov.
The FAA issued a supplemental notice of proposed rulemaking (SNPRM)
to amend 14 CFR part 39 to supersede AD 2018-03-13, Amendment 39-19186
(83 FR 6125, February 13, 2018) (AD 2018-03-13). AD 2018-03-13 applied
to certain GE Model CT7-5A2, CT7-5A3, CT7-7A, CT7-7A1, CT7-9B, CT7-9B1,
CT7-9B2, CT7-9C and CT7-9C3 engines. The SNPRM published in the Federal
Register on July 11, 2023 (88 FR 44068). The SNPRM was prompted by a
comment from GE Aerospace on the notice of proposed rulemaking (NPRM).
GE Aerospace stated that certain engine models were included in
incorrect Figures within the Required Actions paragraph of the NPRM,
which would attribute inaccurate inspection thresholds to those engine
models. Therefore, the FAA issued the SNPRM with a revision to Figures
1 and 2 to include the correct engine models. The FAA also updated the
affected engine models listed in paragraphs (g)(1) and (g)(2) of the
SNPRM to correspond with the corrected engine models referenced in
Figures 1 and 2.
In the SNPRM, the FAA proposed to require initial and repetitive
visual inspections, FPIs, and USIs of the main propeller shaft.
Depending on the results of these inspections, the SNPRM proposed to
require replacing the main propeller shaft. As an optional terminating
action to these inspections, the SNPRM proposed to require revising the
ALS of the existing MM and the operator's existing approved maintenance
program or inspection program, as applicable, to incorporate the tasks
and reduced inspection thresholds for the main propeller shaft. The FAA
is issuing this AD to address the unsafe condition on these products.
Discussion of Final Airworthiness Directive
The FAA received comments from one commenter, GE Aerospace. The
following presents the comment received on the SNPRM and the FAA's
response to that comment.
Request To Remove Typographical Error From SNPRM
GE noted that there is a typological [typographical] error in the
``Proposed AD Requirements in This SNPRM'' paragraph of the SNPRM in
which the words ``at least'' are repeated in succession.
The FAA agrees, however, the ``Proposed AD Requirements in This
SNPRM'' paragraph is not included in this Final Rule. The FAA did not
change this AD as a result of this comment.
The FAA reviewed the relevant data, considered any comments
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 and any
other changes described previously, this AD is adopted as proposed in
the SNPRM. None of the changes will increase the economic burden on any
Related Service Information Under 1 CFR Part 51
The FAA reviewed GE Service Bulletin (SB) CT7-TP 72-0541 R01, dated
November 18, 2021 (GE SB CT7-TP 72-0541). This service information
specifies procedures for performing initial and repetitive visual
inspections, FPIs, and USIs of the main propeller shaft.
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.
Costs of Compliance
The FAA estimates that this AD affects 176 engines installed on
airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:
|Visually inspect, FPI, and USI
the main propeller shaft
||2 work-hours x $85 per hour
The FAA estimates the following costs
to perform the optional
terminating action or to do any necessary replacement that would be
required based on the results of the inspections. The agency has no way
of determining the number of operators that will perform the optional
terminating action or engines that might need this replacement:
|Replace the main propeller shaft
||8 work-hours x $85 per hour =
|Revise the ALS of the MM
||1 work-hour 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 has determined that 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
(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 under the criteria
of the Regulatory Flexibility Act.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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:
a. Removing Airworthiness Directive 2018-03-13, Amendment 39-19186 (83
FR 6125, February 13, 2018); and
b. Adding the following new airworthiness directive: