(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 al-
ready 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 rotat-
ing air HPT front seal has 7,000 cycles or greater since being recon-
figured, 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 installa-
tion.
(ii) If, on July 5, 2019 (the effective date of AD 2019-12-05), the rotat-
ing 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, re-
move the rotating air HPT front seal from service before accumulat-
ing 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 rotat-
ing 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.
(ii) If, on July 5, 2019 (the effective date of AD 2019-12-05), the rotat-
ing 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 ro-
tating 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: ANE-AD-AMOC@faa.gov.
(2) Before using any approved AMOC, notify your appropriate principal in-
spector, 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, Avia-
tion Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burling-
ton, MA 01803; phone: (781) 238-7120; fax: (781) 238-7199; email:
Chris.McGuire@faa.gov.
(l) MATERIAL INCORPORATED BY REFERENCE
None.
Issued on July 29, 2021. Lance T. Gant, Director, Compliance & Airworthi-
ness Division, Aircraft Certification Service.
FOR FURTHER INFORMATION CONTACT: Christopher McGuire, Aviation Safety Eng-
ineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone:
(781) 238-7120; fax: (781) 238-7199; email: Chris.McGuire@faa.gov.
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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:
fleetsupport@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 (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:
Chris.McGuire@faa.gov.
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:
Estimated Costs
| Action |
Labor cost |
Parts cost |
Cost per product |
Cost on U.S. operators |
| Replace the rotating air HPT
front seal |
1 work-hour x $85 per . hour
= $85 |
$344,600 |
$344,685 |
$1,378,740 |
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
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 2019-12-05, Amendment 39-19660 (84
FR 28717, June 20, 2019); and
b. Adding the following new airworthiness directive:
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