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

[Federal Register Volume 86, Number 161 (Tuesday, August 24, 2021)]
[Rules and Regulations]
[Pages 47215-47217]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-18165]



[[Page 47215]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0597; Project Identifier 2019-NE-05-AD; Amendment 
39-21670; AD 2021-16-08]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2019-12-05 
for certain CFM International S.A. (CFM) CFM56-5B, CFM56-5C, and CFM56-
7B model turbofan engines with a certain rotating air high-pressure 
turbine (HPT) front seal. AD 2019-12-05 required replacement of the 
affected rotating air HPT front seal with a part eligible for 
installation. This AD was prompted by cracks found in the rotating air 
HPT front seal. This AD requires replacement of affected rotating air 
HPT front seals installed on CFM CFM56-5B, CFM56-5C, and CFM56-7B model 
turbofan engines that have fewer cycles since being reconfigured than 
the engines affected by AD 2019-12-05. This AD also requires CFM56-5B 
or CFM56-7B model turbofan engines with a reconfigured rotating air HPT 
front seal that was previously operated in a CFM56-5C model turbofan 
engine to follow the removal requirements for the CFM56-5C model 
turbofan engine. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective September 28, 2021.

ADDRESSES: For service information identified in this final rule, 
contact CFM International, S.A., 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 (781) 238-7759. It is 
also available at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2019-0597.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2019-0597; 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: Christopher McGuire, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7120; fax: (781) 238-7199; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2019-12-05, Amendment 39-19660 (84 FR 
28717, June 20, 2019), (AD 2019-12-05). AD 2019-12-05 applied to all 
CFM CFM56-5B, CFM56-5C, and CFM56-7B model turbofan engines with a 
certain rotating air HPT front seal. AD 2019-12-05 required replacement 
of the affected rotating air HPT front seal with a part eligible for 
installation. The actions required by AD 2019-12-05 were interim and 
only addressed the highest risk engines with an affected rotating air 
HPT front seal that have a specified number of cycles since being 
reconfigured.
    The NPRM published in the Federal Register on October 23, 2019 (84 
FR 56709). AD 2019-12-05 was prompted by cracks found in the rotating 
air HPT front seal. In the NPRM, the FAA proposed to retain the 
requirements of AD 2019-12-05 and extend those requirements to engines 
that have fewer cycles since being reconfigured.
    After the NPRM was issued, CFM revised its service information that 
provides instructions for replacing the affected rotating air HPT front 
seal. In addition, the revised service information addresses CFM56-5B 
or CFM56-7B model turbofan engines with a reconfigured rotating air HPT 
front seal that was previously operated in a CFM56-5C model turbofan 
engine, and specifies that those engines follow the removal limits 
established for CFM56-5C model turbofan engines. In addition, the FAA 
determined changes to the proposed AD were necessary based on comments 
received on the NPRM.
    Accordingly, the FAA issued a supplemental notice of proposed 
rulemaking (SNPRM), which published in the Federal Register on March 
23, 2021 (86 FR 15436). In the SNPRM, the FAA proposed to retain the 
requirements of AD 2019-12-05 and expand the applicability to require 
the replacement of affected rotating air HPT front seals installed on 
CFM CFM56-5B, CFM56-5C, and CFM56-7B model turbofan engines that have 
fewer cycles since being reconfigured than the engines affected by AD 
2019-12-05. In the SNPRM, the FAA also proposed to require that CFM56-
5B and CFM56-7B model turbofan engines with a reconfigured rotating air 
HPT front seal that was previously operated in a CFM56-5C model 
turbofan engine follow the removal requirements of the CFM56-5C model 
turbofan engine. 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 on the SNPRM. The 
commenter was The Boeing Company (Boeing). Boeing supported the 
proposed AD without change.

Conclusion

    The FAA reviewed the relevant data, considered the 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. This AD is adopted as proposed in the 
SNPRM.

Related Service Information

    The FAA reviewed CFM Service Bulletin (SB) CFM56-5B S/B 72-1074, 
Revision 02, dated November 6, 2019; CFM SB CFM56-5C S/B 72-0794, 
Revision 02, dated November 6, 2019; and CFM SB CFM56-7B S/B 72-1042, 
Revision 02, dated November 6, 2019. CFM SB CFM56-5B S/B 72-1074, 
Revision 02, contains procedures for replacing the affected rotating 
air HPT front seal on CFM CFM56-5B model turbofan engines. CFM SB 
CFM56-5C S/B 72-0794, Revision 02, contains procedures for replacing 
the affected rotating air HPT front seal on CFM CFM56-5C model turbofan 
engines. CFM SB CFM56-7B S/B 72-1042, Revision 02, contains procedures 
for replacing the affected rotating air HPT front seal on CFM CFM56-7B 
model turbofan engines.

Costs of Compliance

    The FAA estimates that this AD affects 4 engines installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

[[Page 47216]]



                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Replace the rotating air HPT front      1 work-hour x $85 per           $344,600        $344,685      $1,378,740
 seal.                                   hour = $85.
----------------------------------------------------------------------------------------------------------------

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 2019-12-05, Amendment 39-19660 (84 
FR 28717, June 20, 2019); and
0
b. Adding the following new airworthiness directive:

2021-16-08 CFM International, S.A.: Amendment 39-21670; Docket No. 
FAA-2019-0597; Project Identifier 2019-NE-05-AD.

(a) Effective Date

    This airworthiness directive (AD) is effective September 28, 
2021.

(b) Affected ADs

    This AD replaces AD 2019-12-05, Amendment 39-19660 (84 FR 28717, 
June 20, 2019).

(c) Applicability

    This AD applies to:
    (1) CFM International, S.A. (CFM) CFM56-5B1, -5B2, -5B4, -5B5, -
5B6, -5B7, -5B1/P, -5B2/P, -5B3/P, -5B4/P, -5B5/P, -5B6/P, -5B7/P, -
5B8/P, -5B9/P, -5B3/P1, -5B4/P1, -5B1/2P, -5B2/2P, -5B3/2P, -5B4/2P, 
-5B6/2P, -5B9/2P, -5B3/2P1, -5B4/2P1, -7B20, -7B22, -7B24, -7B26, -
7B27, -7B22/B1, -7B24/B1, -7B26/B1, -7B26/B2, -7B27/B1, -7B27/B3, -
7B20/2, -7B22/2, -7B24/2, -7B26/2, -7B27/2, -7B27A model turbofan 
engines with a:
    (i) Rotating air high-pressure turbine (HPT) front seal:
    (A) With part number (P/N) 1795M36P01 or P/N 1795M36P02 and 
serial numbers (S/Ns) GWNDN949 through GWNSE969 or S/Ns GWN000CE 
through GWN0990L, not including S/Ns GWN08ND7, GWN0923A, GWN0971E, 
GWN098A1, GWN098W6, GWN098W8, GWN098WA, and GWN0990G, installed, and
    (B) That has been removed from the original HPT disk and re-
assembled to a different HPT disk.
    (ii) [Reserved]
    (2) CFM CFM56-5C2, -5C2/4, -5C2/F, -5C2/F4, -5C2/G, -5C2/G4, -
5C2/P, -5C3/F, -5C3/F4, -5C3/G, -5C3/G4, -5C3/P, -5C4, -5C4/1, -5C4/
P, -5C4/1P model turbofan engines with a:
    (i) Rotating air HPT front seal:
    (A) With P/N 1795M36P01 or P/N 1795M36P02 and S/Ns GWNDN949 
through GWNSE969 or S/Ns GWN000CE through GWN0990L, not including S/
Ns GWN08ND7, GWN0923A, GWN0971E, GWN098A1, GWN098W6, GWN098W8, 
GWN098WA, and GWN0990G, installed, and
    (B) That has been removed from the original HPT disk and re-
assembled to a different HPT disk.
    (ii) [Reserved]

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
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 
rotating air HPT front seal. The unsafe condition, if not addressed, 
could result in the 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) For all affected CFM CFM56-5B and CFM56-7B model turbofan 
engines:
    (i) If, on July 5, 2019 (the effective date of AD 2019-12-05), 
the rotating air HPT front seal has 7,000 cycles or greater since 
being reconfigured, remove the part from service within 50 cycles 
after July 5, 2019 (the effective date of AD 2019-12-05), or before 
further flight, whichever occurs later, and replace with a part 
eligible for installation.
    (ii) If, on July 5, 2019 (the effective date of AD 2019-12-05), 
the rotating air HPT front seal has between 6,001 and 6,999 cycles, 
inclusive, since being reconfigured, remove the part from service 
within 500 cycles after July 5, 2019 (the effective date of AD 2019-
12-05), but not to exceed 7,050 cycles since being reconfigured, or 
before further flight, whichever occurs later, and replace with a 
part eligible for installation.
    (iii) For all remaining CFM56-5B and CFM56-7B model turbofan 
engines, remove the rotating air HPT front seal from service before 
accumulating 6,500 cycles since being reconfigured, or within 50 
cycles after the effective date of this AD, whichever occurs later.
    (2) For all affected CFM CFM56-5C model turbofan engines:
    (i) If, on July 5, 2019 (the effective date of AD 2019-12-05), 
the rotating air HPT front seal has 4,250 cycles or greater since 
being reconfigured, remove the part from service within 25 cycles 
after July 5, 2019 (the effective date of AD 2019-12-05), within 
1,500 cycles since the last fluorescent penetrant inspection (FPI) 
of the rotating air HPT front seal, or before further flight after 
the effective date of this AD, whichever occurs later, and replace 
with a part eligible for installation.

[[Page 47217]]

    (ii) If, on July 5, 2019 (the effective date of AD 2019-12-05), 
the rotating air HPT front seal has between 3,751 and 4,249 cycles, 
inclusive, since being reconfigured, remove the part from service 
within 250 cycles after July 5, 2019 (the effective date of AD 2019-
12-05), before accumulating 4,275 cycles since being reconfigured, 
within 1,500 cycles since the last FPI of the rotating air HPT front 
seal, or before further flight after the effective date of this AD, 
whichever occurs later, and replace with a part eligible for 
installation.
    (iii) For all remaining CFM CFM56-5C model turbofan engines, 
remove the rotating air HPT front seal from service before 
accumulating 4,000 cycles since being reconfigured, or within 50 
cycles after the effective date of this AD, whichever occurs later.
    (3) For CFM56-5B or CFM56-7B model turbofan engines with an 
affected rotating air HPT front seal that has been operated in a 
CFM56-5C model turbofan engine since being reconfigured, remove the 
rotating air HPT front seal from service using the cycle limits in 
paragraph (g)(2) of this AD.

(h) Definition

    For the purpose of this AD, ``reconfigured'' occurs when a 
rotating air HPT front seal has been removed from the original HPT 
disk and re-assembled to a different HPT disk.

(i) Installation Prohibition

    After the effective date of this AD, do not assemble any 
rotating air HPT front seal with greater than 0 cycles since new, 
having a S/N listed in paragraph (c) of this AD onto a HPT disk 
unless it is the same S/N HPT disk on which it has previously been 
assembled.

(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 Related Information. You may email your request 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.

(k) Related Information

    For more information about this AD, contact Christopher McGuire, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781) 238-7120; fax: (781) 238-7199; 
email: [email protected].

(l) Material Incorporated by Reference

    None.

    Issued on July 29, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-18165 Filed 8-23-21; 8:45 am]
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