[Federal Register Volume 88, Number 65 (Wednesday, April 5, 2023)]
[Rules and Regulations]
[Pages 20059-20062]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-07003]



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 Rules and Regulations
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  Federal Register / Vol. 88, No. 65 / Wednesday, April 5, 2023 / Rules 
and Regulations  

[[Page 20059]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-1405; Project Identifier AD-2022-01070-E; 
Amendment 39-22374; AD 2023-05-05]
RIN 2120-AA64


Airworthiness Directives; CFM International, S.A. Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2021-10-09 
for certain CFM International, S.A. (CFM) CFM56-5B and CFM56-7B model 
turbofan engines with a certain high-pressure turbine (HPT) inner 
stationary seal installed. AD 2021-10-09 required removal, inspection, 
and replacement of the affected HPT inner stationary seal and, 
depending on the findings, replacement of the rotating air HPT front 
seal, HPT rotor blades, and No. 3 ball bearing. This AD was prompted by 
cracks found in the rotating air HPT front seal. After the FAA issued 
AD 2021-10-09, the manufacturer notified the FAA that the service 
information incorrectly lists the year of certain honeycomb repairs and 
that affected HPT inner stationary seals could potentially be installed 
on CFM CFM56-5C model turbofan engines. This AD requires removal, 
inspection, and replacement of the affected HPT inner stationary seal 
and, depending on the findings, replacement of the rotating air HPT 
front seal, HPT rotor blades, and No. 3 ball bearing. This AD also 
revises the applicability to add CFM CFM56-5C model turbofan engines. 
The FAA is issuing this AD to address the unsafe condition on these 
products.

DATES: This AD is effective May 10, 2023.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of May 10, 2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov by 
searching for and locating Docket No. FAA-2022-1405; 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 CFM service information identified in this final rule, 
contact CFM International Inc., Aviation Operations Center, 1 Neumann 
Way, M/D Room 285, Cincinnati, OH 45125; phone: (877) 432-3272; email: 
[email protected].
     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 by searching for and locating Docket 
No. FAA-2022-1405.

FOR FURTHER INFORMATION CONTACT: Kevin Clark, Aviation Safety Engineer, 
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 
(781) 238-7088; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2021-10-09, Amendment 39-21542 (86 FR 
27264, May 20, 2021) (AD 2021-10-09). AD 2021-10-09 applied to certain 
CFM CFM56-5B and CFM56-7B model turbofan engines with an HPT inner 
stationary seal, part number 1808M56G01, installed. The NPRM published 
in the Federal Register on December 1, 2022 (87 FR 73683). The NPRM was 
prompted by cracks found in the rotating air HPT front seal. After the 
FAA issued AD 2021-10-09, the manufacturer notified the FAA that the 
service information referenced in AD 2021-10-09 incorrectly listed the 
year of certain honeycomb repairs. Additionally, the manufacturer 
notified the FAA that affected HPT inner stationary seals could 
potentially be installed on CFM CFM56-5C model turbofan engines. In the 
NPRM, the FAA proposed to require removal, inspection, and replacement 
of the affected HPT inner stationary seal and, depending on the 
findings, replacement of the rotating air HPT front seal, HPT rotor 
blades, and No. 3 ball bearing. In the NPRM, the FAA also proposed to 
revise the applicability to add CFM CFM56-5C model turbofan engines.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from three commenters. The commenters 
were Air Line Pilots Association, International (ALPA), American 
Airlines (AA), and The Boeing Company (Boeing). The following presents 
the comments received on the NPRM and the FAA's response to each 
comment.

Support for the AD

    ALPA and Boeing supported the NPRM without change.

Request To Specify Service Bulletins and Revision Numbers

    AA requested that the FAA specify service bulletins and their 
respective revision numbers throughout this AD. AA stated that 
paragraph (c), Applicability, references the service bulletins as 
follows, CFM Service Bulletin (SB) CFM56-5B S/B 72-0952, Revision 02, 
dated August 10, 2022 (CFM SB CFM56-5B S/B 72-0952); CFM SB CFM56-5C S/
B 72-0796, Revision 02, dated August 10, 2022 (CFM SB CFM56-5C S/B 72-
0796); CFM SB CFM56-7B S/B 72-1054, Revision 02, dated August 10, 2022 
(CFM SB CFM56-7B S/B 72-1054). AA noted that the SB format within the 
parentheses abridges the complete description of the service bulletins 
and is used in proposed paragraphs (g)(2), (h)(2)(i), and (2)(ii). AA 
reasoned that this SB format could be interpreted as the original 
(basic) service bulletin, which provides outdated accomplishment 
instructions and could contribute to errors during the accomplishment 
of this AD.
    The FAA established a shorthand notation in paragraph (c), 
Applicability,

[[Page 20060]]

of the NPRM for each service bulletin, which contained the full 
citation, including the manufacturer name, SB number, revision number, 
and date, followed by the shorthand notation. The FAA then used the 
established shorthand notation to reference the service bulletins in 
paragraphs (g)(2), (h)(2)(i), and (2)(ii), as applicable, of the NPRM. 
Avoiding the use of the shorthand notation and including the revision 
numbers and dates for each SB reference is unnecessary, as the 
referenced service information is defined in both the preamble and the 
AD body. The FAA did not change this AD as a result of this comment.

Request To Revise Paragraph (c) of This AD

    AA requested that the FAA revise paragraph (c), Applicability, of 
this AD to include the following, ``This AD does not apply to affected 
CFM56-5B and CFM56-7B model turbofan engines with the affected HPT 
inner stationary seal installed if the seal has been repaired as 
specified in CFM56 Engine Shop Manual (ESM), 72-41-03, REPAIR 003 after 
December 31, 2012 and prior to the effective date, June 24, 2021, of 
FAA AD 2021-10-09.'' AA reasoned that this language was part of AD 
2021-10-09, paragraph (c), Applicability. The exclusion of this text 
from the final rule would make the population of HPT inner stationary 
seals, within the previously identified time frame, applicable to the 
proposed AD.
    In response to this comment, the FAA has revised paragraph (c), 
Applicability, of this AD to include: ``This AD does not apply to 
affected CFM CFM56-5B, CFM56-5C, and CFM56-7B model turbofan engines 
with the affected HPT inner stationary seal installed if the seal has 
been repaired as specified in CFM56-5B ESM, 72-41-03, REPAIR 003; 
CFM56-5C ESM, 72-41-03, REPAIR 003; or CFM56-7B ESM, 72-41-03, REPAIR 
003, after December 31, 2012.''

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 NPRM. None of the changes will increase the economic burden on 
any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed the following service information:
     CFM SB CFM56-5C S/B 72-0796, Revision 02, dated August 10, 
2022.
     CFM SB CFM56-5B S/B 72-0952, Revision 02, dated August 10, 
2022.
     CFM SB CFM56-7B S/B 72-1054, Revision 02, dated August 10, 
2022.
    This service information, differentiated by engine model, specifies 
procedures for inspecting the HPT inner stationary seal honeycomb. 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 210 engines installed on 
airplanes of U.S. registry. Operators have the option to replace or 
repair the affected HPT inner stationary seal. The parts cost includes 
the estimated costs for replacement with a repaired HPT inner 
stationary seal.
    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
----------------------------------------------------------------------------------------------------------------
Replace HPT inner stationary seal.....  1 work-hour x $85 per             $7,910          $7,995      $1,678,950
                                         hour = $85.
Inspect HPT inner stationary seal.....  1 work-hour x $85 per                  0              85          17,850
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
inspection. The agency has no way of determining the number of engines 
that might need these replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace rotating air HPT front seal........  1 work-hour x $85 per hour = $85...        $344,600        $344,685
Replace HPT rotor blades (pair)............  1 work-hour x $85 per hour = $85...          31,000          31,085
Replace No. 3 ball bearing.................  1 work-hour x $85 per hour = $85...          30,000          30,085
----------------------------------------------------------------------------------------------------------------

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:

[[Page 20061]]

    (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 2021-10-09, Amendment 39-21542 (86 
FR 27264, May 20, 2021); and
0
b. Adding the following new airworthiness directive:

2023-05-05 CFM International, S.A.: Amendment 39-22374; Docket No. 
FAA-2022-1405; Project Identifier AD-2022-01070-E.

(a) Effective Date

    This airworthiness directive (AD) is effective May 10, 2023.

(b) Affected ADs

    This AD replaces AD 2021-10-09, Amendment 39-21542 (86 FR 27264, 
May 20, 2021) (AD 2021-10-09).

(c) Applicability

    This AD applies to CFM International, S.A. (CFM) model turbofan 
engines identified in Table 1 to paragraph (c) of this AD with an 
installed high-pressure turbine (HPT) inner stationary seal, part 
number (P/N) 1808M56G01, that has a serial number (S/N) listed in 
Table 1 of CFM Service Bulletin (SB) CFM56-5B S/B 72-0952, Revision 
02, dated August 10, 2022 (CFM SB CFM56-5B S/B 72-0952); Table 1 of 
CFM SB CFM56-5C S/B 72-0796, Revision 02, dated August 10, 2022 (CFM 
SB CFM56-5C S/B 72-0796); or Table 1 of CFM SB CFM56-7B S/B 72-1054, 
Revision 02, dated August 10, 2022 (CFM SB CFM56-7B S/B 72-1054). 
This AD does not apply to affected CFM CFM56-5B, CFM56-5C, and 
CFM56-7B model turbofan engines with the affected HPT inner 
stationary seal installed if the seal has been repaired as specified 
in CFM56-5B Engine Shop Manual (ESM), 72-41-03, REPAIR 003; CFM56-5C 
ESM, 72-41-03, REPAIR 003; or CFM56-7B ESM, 72-41-03, REPAIR 003, 
after December 31, 2012.

          Table 1 to Paragraph (c)--CFM Model Turbofan Engines
------------------------------------------------------------------------
             Make                                Model
------------------------------------------------------------------------
CFM..........................  CFM56-5B1, CFM56-5B1/2P, CFM56-5B1/3,
                                CFM56-5B1/P, CFM56-5B2, CFM56-5B2/2P,
                                CFM56-5B2/3, CFM56-5B2/P, CFM56-5B3/2P,
                                CFM56-5B3/2P1, CFM56-5B3/3, CFM56-5B3/
                                3B1, CFM56-5B3/P, CFM56-5B3/P1, CFM56-
                                5B4, CFM56-5B4/2P, CFM56-5B4/2P1, CFM56-
                                5B4/3, CFM56-5B4/3B1, CFM56-5B4/P, CFM56-
                                5B4/P1, CFM56-5B5, CFM56-5B5/3, CFM56-
                                5B5/P, CFM56-5B6, CFM56-5B6/2P, CFM56-
                                5B6/3, CFM56-5B6/P, CFM56-5B7, CFM56-5B7/
                                3, CFM56-5B7/P, CFM56-5B8/3, CFM56-5B8/
                                P, CFM56-5B9/2P, CFM56-5B9/3, CFM56-5B9/
                                P.
CFM..........................  CFM56-5C2, CFM56-5C2/4, CFM56-5C2/F,
                                CFM56-5C2/F4, CFM56-5C2/G, CFM56-5C2/G4,
                                CFM56-5C2/P, CFM56-5C3/F, CFM56-5C3/F4,
                                CFM56-5C3/G, CFM56-5C3/G4, CFM56-5C3/P,
                                CFM56-5C4, CFM56-5C4/1, CFM56-5C4/1P,
                                CFM56-5C4/P.
CFM..........................  CFM56-7B20, CFM56-7B20/2, CFM56-7B20/3,
                                CFM56-7B20E, CFM56-7B22, CFM56-7B22/2,
                                CFM56-7B22/3, CFM56-7B22/3B1, CFM56-7B22/
                                B1, CFM56-7B22E, CFM56-7B22E/B1, CFM56-
                                7B24, CFM56-7B24/2, CFM56-7B24/3, CFM56-
                                7B24/3B1, CFM56-7B24/B1, CFM56-7B24E,
                                CFM56-7B24E/B1, CFM56-7B26, CFM56-7B26/
                                2, CFM56-7B26/3, CFM56-7B26/3B1, CFM56-
                                7B26/3B2, CFM56-7B26/3B2F, CFM56-7B26/
                                3F, CFM56-7B26/B1, CFM56-7B26/B2, CFM56-
                                7B26E, CFM56-7B26E/B1, CFM56-7B26E/B2,
                                CFM56-7B26E/B2F, CFM56-7B26E/F, CFM56-
                                7B27, CFM56-7B27/2, CFM56-7B27/3, CFM56-
                                7B27/3B1, CFM56-7B27/3B1F, CFM56-7B27/
                                3B3, CFM56-7B27/3F, CFM56-7B27/B1, CFM56-
                                B27/B3, CFM56-7B27A, CFM56-7B27A/3,
                                CFM56-7B27AE, CFM56-7B27E, CFM56-7B27E/
                                B1, CFM56-7B27E/B1F, CFM56-7B27E/B3,
                                CFM56-7B27E/F.
------------------------------------------------------------------------

(d) Subject

    Joint Aircraft System Component (JASC) Code 7230, Turbine Engine 
Compressor Section.

(e) Unsafe Condition

    This AD was prompted by cracks found in the rotating air HPT 
front seal. The FAA is issuing this AD to prevent failure of the HPT 
inner stationary seal and the rotating air HPT front seal. The 
unsafe condition, if not addressed, could result in uncontained 
release of the rotating air HPT front seal, damage to the engine, 
and damage to the airplane.

(f) Compliance

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

(g) Required Actions

    (1) At the next engine shop visit after the effective date of 
this AD, remove the affected HPT inner stationary seal and replace 
with an HPT inner stationary seal that is eligible for installation.
    (2) After removing the affected HPT inner stationary seal 
required by paragraph (g)(1) of this AD, inspect the removed HPT 
inner stationary seal for honeycomb separation in accordance with 
the Accomplishment Instructions, paragraph 3.C.(1), of CFM SB CFM56-
5B S/B 72-0952; CFM SB CFM56-5C S/B 72-0796; or CFM SB CFM56-7B S/B 
72-1054, as applicable by engine model.
    (3) If honeycomb separation is found during the inspection 
required by paragraph (g)(2) of this AD, before further flight:
    (i) Remove the rotating air HPT front seal from service and 
replace with a rotating air HPT front seal that is eligible for 
installation.
    (ii) Remove the HPT rotor blades and replace with HPT rotor 
blades eligible for installation.
    (iii) Remove the No. 3 ball bearing from service and replace 
with a No. 3 ball bearing eligible for installation.

(h) Definitions

    (1) For the purpose of this AD, an ``engine shop visit'' is the 
induction of an engine into the shop for maintenance involving the 
separation of pairs of major mating engine case flanges, except for 
the following situations, which do not constitute an engine shop 
visit.
    (i) Separation of engine flanges solely for the purpose of 
transportation of the engine without subsequent maintenance.
    (ii) Separation of engine flanges solely for the purpose of 
replacing the fan or propulsor without subsequent maintenance.

[[Page 20062]]

    (2) For the purpose of this AD, an ``HPT inner stationary seal 
that is eligible for installation'' is an HPT inner stationary seal:
    (i) That is not listed in Table 1 of CFM SB CFM56-5B S/B 72-
0952; Table 1 of CFM SB CFM56-5C S/B 72-0796; or Table 1 CFM SB 
CFM56-7B S/B 72-1054; or
    (ii) With a P/N 1808M56G01 and an S/N listed in Table 1 of CFM 
SB CFM56-5B S/B 72-0952; Table 1 of CFM SB CFM56-5C S/B 72-0796; or 
Table 1 of CFM SB CFM56-7B S/B 72-1054, that has been repaired as 
specified in CFM56-5B ESM, 72-41-03, REPAIR 003; CFM56-5C ESM, 72-
41-03, REPAIR 003; or CFM56-7B ESM, 72-41-03, REPAIR 003, as 
applicable by engine model, after December 31, 2012.
    (3) For the purpose of this AD, a ``rotating air HPT front seal 
that is eligible for installation'' is any rotating air HPT front 
seal that was not removed from service as a result of the inspection 
of the HPT inner stationary seal required by paragraph (g)(2) of 
this AD in which there was a finding of honeycomb separation.
    (4) For the purpose of this AD, ``HPT rotor blades eligible for 
installation'' are new HPT rotor blades with zero flight hours since 
new or HPT rotor blades that have been inspected and returned to a 
serviceable condition using FAA-approved maintenance procedures.
    (5) For the purpose of this AD, a ``No. 3 ball bearing eligible 
for installation'' is any No. 3 ball bearing that was not removed 
from service as a result of the inspection of the HPT inner 
stationary seal required by paragraph (g)(2) of this AD in which 
there was a finding of honeycomb separation.

(i) Credit for Previous Actions

    You may take credit for the actions specified in paragraphs 
(g)(1) through (3) of this AD, if you performed those actions before 
the effective date of this AD using CFM SB CFM56-5B S/B 72-0952, 
Revision 01, dated January 15, 2020, CFM SB CFM56-7B S/B 72-1054, 
Revision 01, dated January 15, 2020, or CFM SB CFM56-5C S/B 72-0796 
Revision 01, dated January 15, 2020.

(j) 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 (k) 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.
    (3) AMOCs approved for AD 2021-10-09 (86 FR 27264, May 20, 2021) 
are approved as AMOCs for the corresponding provisions of this AD.

(k) Related Information

    For more information about this AD, contact Kevin Clark, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781) 238-7088; email: 
[email protected].

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference 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) CFM Service Bulletin CFM56-5C S/B 72-0796, Revision 02, 
dated August 10, 2022.
    (ii) CFM Service Bulletin CFM56-5B S/B 72-0952, Revision 02, 
dated August 10, 2022.
    (iii) CFM Service Bulletin CFM56-7B S/B 72-1054, Revision 02, 
dated August 10, 2022.
    (3) For CFM service information identified in this AD, contact 
CFM International Inc., Aviation Operations Center, 1 Neumann Way, 
M/D Room 285, Cincinnati, OH 45125; phone: (877) 432-3272; email: 
[email protected].
    (4) 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on March 5, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-07003 Filed 4-4-23; 8:45 am]
BILLING CODE 4910-13-P


