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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2022-1405; Project Identifier AD-2022-01070-E]
RIN 2120-AA64
Airworthiness Directives; CFM International, S.A. Turbofan
Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede Airworthiness Directive
(AD)
2021-10-09, which applies to all 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 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.
Since the FAA issued AD 2021-10-09, the manufacturer notified the FAA
that the service information incorrectly lists 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. This proposed AD would 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.
This proposed AD would also revise the applicability to add CFM CFM56-
5C model turbofan engines. The FAA is proposing this AD to address the
unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by January
17,
2023.
ADDRESSES: You may send comments, using the procedures found in
14 CFR
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to regulations.gov. Follow
the instructions for submitting comments.
Fax: (202) 493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
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 NPRM, any comments
received, and other information. The street address for Docket
Operations is listed above.
Material Incorporated by Reference:
For CFM service information identified in this NPRM,
contact CFM International Inc., Aviation Operations Center, 1 Neumann
Way, M/D Room 285, Cincinnati, OH 45125; phone: (877) 432-3272; email:
aviation.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 (817) 222-5110.
FOR FURTHER INFORMATION CONTACT: Kevin Clark, Aviation Safety Engineer,
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone:
(781) 238-7088; email: kevin.m.clark@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include ``Docket No. FAA-2022-1405; Project Identifier
AD-2022-01070-E'' at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
the proposal because of those comments.
Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
regulations.gov, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this NPRM.
Confidential Business Information
CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as ``PROPIN.'' The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to Kevin
Clark, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803. Any commentary that the FAA receives which is not
specifically designated as CBI will be placed in the public docket for
this rulemaking.
Background
The FAA issued AD 2021-10-09, Amendment 39-21542 (86 FR 27264, May
20, 2021) (AD 2021-10-09), for all CFM CFM56-5B and CFM56-7B model
turbofan engines with an HPT inner stationary seal, part number (P/N)
1808M56G01, installed. AD 2021-10-09 was prompted by cracks found in
the rotating air HPT front seal. After investigation, CFM determined
that the HPT inner stationary seal, P/N 1808M56G01, may not have
received the correct braze heat treat cycle at the time of the
honeycomb replacement. As a result, the affected HPT inner stationary
seal may have a condition that could lead to a localized separation
of the replaced honeycomb, which may reduce the life of the rotating
air HPT front seal. AD 2021-10-09 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. The agency issued AD 2021-10-09 to
prevent failure of the HPT inner stationary seal and the rotating air
HPT front seal, which could result in uncontained release of the
rotating air HPT front seal, damage to the engine, and damage to the
airplane.
Actions Since AD 2021-10-09 Was Issued
Since the FAA issued AD 2021-10-09, the manufacturer notified the
FAA that the service information, which is incorporated by reference,
incorrectly lists the year of certain honeycomb repairs. The
manufacturer subsequently published revised service information that
establishes a single date for the honeycomb repairs. Additionally, the
manufacturer notified the FAA that affected HPT inner stationary seals
could be installed on CFM CFM56-5C model turbofan engines. The FAA,
therefore, determined that the unsafe condition is likely to exist or
develop on CFM CFM56-5C model turbofan engines with an affected HPT
inner stationary seal installed.
FAA's Determination
The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop on other
products of the same type design.
Related Service Information Under 1 CFR Part 51
The FAA reviewed the following service information:
CFM Service Bulletin (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 ADDRESSES.
Proposed AD Requirements in This NPRM
This proposed AD would retain none of the requirements of AD 2021-
10-09. This proposed AD would 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. This proposed AD would also revise the
applicability to add CFM CFM56-5C model turbofan engines.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 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 proposed
AD:
Estimated Costs
|
Action
|
Labor cost
|
Parts cost
|
Cost per
product
|
Cost on
U.S. operators
|
| Replace HPT inner stationary
seal |
1 work-hour x $85 per hour =
$85 |
$7,910
|
$7,995
|
$1,678,950
|
| Inspect HPT inner stationary
seal |
1 work-hour x $85 per hour =
$85 |
0
|
85
|
17,850
|
The FAA estimates the following costs
to do any necessary
replacements that would be required based on the results of the
proposed inspection. The agency has no way of determining the number of
engines that might need these replacements:
On-Condition Costs
|
Action
|
Labor cost
|
Parts cost
|
Cost per
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 determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 the proposed
regulation:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Would not affect intrastate aviation in Alaska, and
(3) Would 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 Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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 2021-10-09, Amendment 39-21542 (86
FR 27264, May 20, 2021); and
b. Adding the following new airworthiness directive:
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