
[Federal Register Volume 88, Number 213 (Monday, November 6, 2023)]
[Rules and Regulations]
[Pages 76117-76122]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-24386]


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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]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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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, 
2023.

ADDRESSES: 
    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: ge.com">aviation.fleetsupport@ae.ge.com; website: 
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. 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: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    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

Comments

    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.

Conclusion

    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 
operator.

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.

[[Page 76118]]

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:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Visually inspect, FPI, and USI the      2 work-hours x $85 per                $0            $170         $29,920
 main propeller shaft.                   hour = $170.
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    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:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace the main propeller shaft..............  8 work-hours x $85 per hour =            $48,360         $49,040
                                                 $680.
Revise the ALS of the MM......................  1 work-hour x $85 per hour = $85               0              85
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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 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 
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 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:
0
a. Removing Airworthiness Directive 2018-03-13, Amendment 39-19186 (83 
FR 6125, February 13, 2018); and
0
b. Adding the following new airworthiness directive:

2023-21-07 General Electric Company: Amendment 39-22579; Docket No. 
FAA-2022-1314; Project Identifier AD-2021-00811-E.

(a) Effective Date

    This airworthiness directive (AD) is effective December 11, 
2023.

(b) Affected ADs

    This AD replaces AD 2018-03-13, Amendment 39-19186 (83 FR 6125, 
February 13, 2018).

(c) Applicability

    This AD applies to 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.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7210, Turbine Engine 
Reduction Gear.

(e) Unsafe Condition

    This AD was prompted by an in-flight failure of a main propeller 
shaft on a GE Model CT7-9B model engine, resulting in the loss of 
the propeller. The FAA is issuing this AD to prevent failure of the 
main propeller shaft. The unsafe condition, if not addressed, could 
cause in-flight loss of the propeller, loss of engine thrust 
control, and damage to the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    (1) For affected CT7-5A2, CT7-5A3, CT7-9B, CT7-9B1, and CT7-9B2 
model engines, using the compliance times specified in Figure 1 to 
paragraph (g)(1) of this AD, perform initial and repetitive visual 
inspections, fluorescent penetrant inspections (FPIs), and 
ultrasonic inspections (USIs) of the main propeller shaft.
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[GRAPHIC] [TIFF OMITTED] TR06NO23.056

    (2) For affected CT7-7A, CT7-7A1, CT7-9C, and CT7-9C3 model 
engines, using the compliance times specified in Figure 2 to 
paragraph (g)(2) of this AD, perform initial and repetitive visual 
inspections, FPIs, and USIs of the main propeller shaft.
[GRAPHIC] [TIFF OMITTED] TR06NO23.057

    (3) Perform the visual inspections, FPIs, and USIs required by 
paragraphs (g)(1) and (2) of this AD as follows:
    (i) Prior to performance of the inspections, clean the main 
propeller shaft flange using the Accomplishment Instructions, 
paragraph 3.B., of GE Service Bulletin (SB) CT7-TP 72-0541 R01, 
dated November 18, 2021 (GE SB CT7-TP 72-0541).

[[Page 76120]]

    (ii) Visually inspect the main propeller shaft for wear, 
corrosion, and cracking using the Accomplishment Instructions, 
paragraph 3.C.(1), of GE SB CT7-TP 72-0541.
    (iii) Spot-FPI the area on the main propeller shaft flange face 
using the Accomplishment Instructions, paragraph 3.C.(2)(a), of GE 
SB CT7-TP 72-0541.
    (iv) USI the two dowel pin holes of the main propeller shaft 
using the Accomplishment Instructions, paragraph 3.C.(3)(a), of GE 
SB CT7-TP 72-0541.
    (4) If a crack or rejectable indication is found during the 
initial and repetitive visual inspections, FPIs, or USIs required by 
paragraphs (g)(1) through (3) of this AD, before further flight, 
remove the main propeller shaft from service and replace it with a 
part eligible for installation.
    (5) For all affected engines, if the main propeller shaft CSN is 
unknown, use the propeller gearbox (PGB) CSN. If the PGB CSN is 
unknown, assume the inspection threshold is exceeded.

(h) Optional Terminating Action

    Accomplishing the actions in paragraphs (h)(1) through (4) of 
this AD, as applicable by engine model, constitutes terminating 
action for the inspections required by paragraphs (g)(1) through (3) 
of this AD.
    (1) For affected CT7-5A2, CT7-5A3, CT7-7A, and CT7-7A1 model 
engines, revise the airworthiness limitations section (ALS) of the 
existing maintenance manual (MM) and the operator's existing 
approved maintenance program or inspection program, as applicable, 
by incorporating the information in Figure 3 to paragraph (h)(1) of 
this AD.
[GRAPHIC] [TIFF OMITTED] TR06NO23.058

    (2) For affected CT7-9B, CT7-9B1, CT7-9B2, CT7-9C, and CT7-9C3 
model engines, revise the ALS of the existing MM and the operator's 
existing approved maintenance program or inspection program, as 
applicable, by incorporating the information in Figure 4 to 
paragraph (h)(2) of this AD.

[[Page 76121]]

[GRAPHIC] [TIFF OMITTED] TR06NO23.059

    (3) Thereafter, except as provided in paragraph (k) of this AD, 
no alternative inspection times or intervals may be approved for 
this main propeller shaft.
    (4) The optional terminating actions in paragraphs (h)(1) and 
(2) of this AD may be performed by the owner/operator (pilot) 
holding at least a private pilot certificate and must be entered 
into the aircraft records showing compliance with this AD in 
accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The record must 
be maintained as required by 14 CFR 91.417, 121.380, or 135.439.

(i) Definition

    For the purpose of this AD, a ``part eligible for installation'' 
is a main propeller shaft that has been inspected in accordance with 
paragraphs (g)(1) or (2), and (3) of this AD, and there was no crack 
or rejectable indication.

(j) Credit for Previous Actions

    You may take credit for the initial visual inspection, FPI, and 
USI required by paragraphs (g)(1) through (3) of this AD if you 
performed these initial inspections before the effective date of 
this AD in accordance with GE SB CT7-TP 72-0541 R00, dated September 
9, 2021.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, AIR-520 Continued Operational Safety 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 AIR-520 Continued 
Operational Safety Branch, send it to the attention of the person 
identified in paragraph (l) of this AD and email it 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.

(l) Additional Information

    For more information about this AD, contact Sungmo Cho, Aviation 
Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; 
phone: (781) 238-7241; email: [email protected].

[[Page 76122]]

(m) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) General Electric Company (GE) Service Bulletin CT7-TP 72-
0541 R01, dated November 18, 2021.
    (ii) [Reserved]
    (3) For GE service information identified in this AD, contact 
General Electric Company, 1 Neumann Way, Cincinnati, OH 45215; 
phone: (513) 552-3272; email: ge.com">aviation.fleetsupport@ae.ge.com; 
website: ge.com.
    (4) You may view this service information at 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.
    (5) You may view this material at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on October 20, 2023.
Ross Landes,
Deputy Director for Regulatory Operations, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2023-24386 Filed 11-3-23; 8:45 am]
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