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

[Federal Register Volume 86, Number 84 (Tuesday, May 4, 2021)]
[Rules and Regulations]
[Pages 23599-23602]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-09507]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0346; Project Identifier AD-2021-00465-E; 
Amendment 39-21539; AD 2021-10-06]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain CFM International, S.A. (CFM) LEAP-1B model turbofan engines. 
This AD was prompted by multiple reports of pressure sub-system (PSS) 
unit faults due to pressure transducer corrosion following extended 
storage periods. For an engine in service, this AD requires checks for 
engine maintenance messages related to the pressure transducer and, 
depending on the results of the check, replacement of the PSS unit 
before further flight. The AD requires this repetitive check for faults 
prior to each flight until the PSS has accumulated at least 15 hours of 
electrical power. For an engine not in service, this AD requires 
applying electrical power to the PSS unit before further flight. The 
FAA is issuing this AD to address the unsafe condition on these 
products.

DATES: This AD is effective May 10, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of May 10, 
2021.
    The FAA must receive comments on this AD by June 18, 2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
    <bullet> Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
    <bullet> Fax: (202) 493-2251.
    <bullet> 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.
    <bullet> Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    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; fax: (877) 432-
3329; 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-2021-0346.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0346; 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 street address for the 
Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Mehdi Lamnyi, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7743; fax: (781) 238-7199; email: 
[email protected].

[[Page 23600]]


SUPPLEMENTARY INFORMATION:

Background

    In April 2021, the FAA received a report from CFM, the engine 
manufacturer, of numerous instances of PSS unit faults. The 
manufacturer reported these faults have been occurring since October 
2020 and are a result of pressure transducer corrosion following 
extended storage periods. The manufacturer's investigation found that 
certain PSS units, identified by serial number, have been exposed to 
conditions that make pressure transducers in these units susceptible to 
an increased rate of faults. These conditions are moisture ingress from 
long-term on-wing storage, coupled with certain manufacturing processes 
of the affected pressure transducers. Together these conditions can 
cause corrosion and subsequent electrical shorting of the pins in the 
pressure transducer. This short can result in transmittal of erroneous 
pressure sensor signals to the electronic engine control. Erroneous 
pressure input from the pressure transducers in the PSS unit has the 
potential to prevent engine control from meeting thrust demand, thereby 
resulting in the loss of engine thrust control. Further, the engine 
manufacturer found that if transmission of erroneous pressure sensor 
signals were to occur, it would occur within the first 15 hours of 
electrical power to the PSS unit after the extended storage period is 
completed. Therefore, the manufacturer recommended that, for engines 
with fewer than 15 hours of electrical power applied to the PSS unit 
within the past 90 days, operators either perform a check for engine 
maintenance messages related to the pressure transducer prior to each 
flight or apply electrical power to the PSS unit until the PSS unit has 
accumulated 15 hours or more of electrical power. The FAA is mandating 
these recommendations in this AD.
    This condition, if not addressed, could result in loss of engine 
thrust control and reduced control of the airplane. The FAA is issuing 
this AD to address the unsafe condition on these products.

FAA's Determination

    The FAA is issuing this AD because the agency has determined the 
unsafe condition described previously is likely to exist or develop in 
other products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed CFM Service Bulletin (SB) LEAP-1B-73-00-0038-01A-
930A-D, Issue 002-00, dated 2021-04-25, excluding FADEC Alliance SB 
LEAP-1B/73-012, Issue 001, dated 2021-04-23 (which is attached to the 
CFM SB). This SB identifies PSS units with susceptible pressure 
transducers. This SB also specifies procedures for checking the engine 
maintenance messages related to the pressure transducer and applying 
electrical power to the PSS unit. 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.

AD Requirements

    For an engine in service, this AD requires checks for engine 
maintenance messages related to the pressure transducer and, depending 
on the results of the checks, replacement of the PSS unit before 
further flight. This AD requires this repetitive check for faults prior 
to each flight until the PSS unit has accumulated at least 15 hours of 
electrical power. For an engine not in service, this AD requires 
applying electrical power to the PSS unit prior to returning the engine 
to service.

Interim Action

    The FAA considers this AD to be an interim action. This unsafe 
condition is still under investigation by the manufacturer and, 
depending on the results of that investigation, the FAA may consider 
further rulemaking action.

Justification for Immediate Adoption and Determination of the Effective 
Date

    Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5 
U.S.C. 551 et seq.) authorizes agencies to dispense with notice and 
comment procedures for rules when the agency, for ``good cause,'' finds 
that those procedures are ``impracticable, unnecessary, or contrary to 
the public interest.'' Under this section, an agency, upon finding good 
cause, may issue a final rule without providing notice and seeking 
comment prior to issuance. Further, section 553(d) of the APA 
authorizes agencies to make rules effective in less than thirty days, 
upon a finding of good cause.
    An unsafe condition exists that requires the immediate adoption of 
this AD without providing an opportunity for public comments prior to 
adoption. The FAA has found that the risk to the flying public 
justifies foregoing notice and comment prior to adoption of this rule. 
As previously noted, there have been numerous instances of PSS units 
faulting in the last few months. These PSS unit failures can impact the 
capability of the engine control to meet commanded thrust and may lead 
to a loss of engine thrust control and reduced control of the airplane. 
Therefore, the risk created by this unsafe condition requires prompt 
action, and the FAA is mandating the compliance time for the required 
action as before further flight. Accordingly, notice and opportunity 
for prior public comment are impracticable and contrary to the public 
interest pursuant to 5 U.S.C. 553(b)(3)(B).
    In addition, the FAA finds that good cause exists pursuant to 5 
U.S.C. 553(d) for making this amendment effective in less than 30 days, 
for the same reasons the FAA found good cause to forego notice and 
comment. Because of the need for operators to begin the required checks 
prior to each flight or application of electrical power to the PSS 
unit, the FAA has made this AD effective 5 days after the date of 
publication.

Comments Invited

    The FAA invites you to send any written data, views, or arguments 
about this final rule. Send your comments to an address listed under 
ADDRESSES. Include ``Docket No. FAA-2021-0346 and Project Identifier 
AD-2021- 00465-E'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the final rule, 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 
this final rule 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 
https://www.regulations.gov, including any personal information you 
provide. The agency will also post a report summarizing each 
substantive verbal contact received about this final rule.

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 AD 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 AD, 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

[[Page 23601]]

will treat such marked submissions as confidential under the FOIA, and 
they will not be placed in the public docket of this AD. Submissions 
containing CBI should be sent to Mehdi Lamnyi, 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.

Regulatory Flexibility Act

    The requirements of the Regulatory Flexibility Act (RFA) do not 
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt 
a rule without prior notice and comment. Because FAA has determined 
that it has good cause to adopt this rule without prior notice and 
comment, RFA analysis is not required.

Costs of Compliance

    The FAA estimates that this AD affects 158 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
----------------------------------------------------------------------------------------------------------------
Check for engine maintenance messages.  0.5 work-hours x $85 per              $0          $42.50          $6,715
                                         hour = $42.50.
Apply electrical power to PSS unit....  15 work-hours x $85 per                0           1,275         201,450
                                         hour = $1,275.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacement that would be required based on the results of the check 
for engine maintenance messages related to the pressure transducer. The 
agency has no way of determining the number of aircraft that might need 
this replacement:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace PSS unit..............................  1 work-hour x $85 per hour = $85        $159,657        $159,742
----------------------------------------------------------------------------------------------------------------

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

    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, and
    (2) Will not affect intrastate aviation in Alaska.

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 adding the following new airworthiness 
directive:

2021-10-06 CFM International, S.A.: Amendment 39-21539; Docket No. 
FAA-2021-0346; Project Identifier AD-2021-00465-E.

(a) Effective Date

    This airworthiness directive (AD) is effective May 10, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to CFM International S.A. (CFM) LEAP-1B21, -
1B23, -1B25, -1B27, -1B28, -1B28B1, -1B28B2, -1B28B3, -1B28B2C, -
1B28BBJ1, and -1B28BBJ2 model turbofan engines with a pressure sub-
system (PSS) unit with a serial number (S/N) listed in Additional 
Information, Paragraph 6.A. Table 1 of CFM Service Bulletin (SB) 
LEAP-1B-73-00-0038-01A-930A-D, Issue 002-00, dated 2021-04-25 (SB 
LEAP-1B-73-0038), installed.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7600, Engine 
Controls.

(e) Unsafe Condition

    This AD was prompted by multiple reports of PSS unit faults due 
to pressure transducer corrosion following extended storage periods. 
The FAA is issuing this AD to prevent erroneous pressure sensor 
signals that can impact engine thrust control. The unsafe condition, 
if not addressed, could result in loss of engine thrust control and 
reduced control of the airplane.

(f) Compliance

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

(g) Required Actions

    (1) For an engine in service on the effective date of this AD 
that has accumulated fewer than 15 hours of electrical power applied 
to the PSS unit within the past 90 days, perform one of the 
following actions:
    (i) Prior to each flight, perform a check for the engine 
maintenance messages listed in the Accomplishment Instructions, 
paragraph

[[Page 23602]]

5.B.(2)(a)2, of SB LEAP-1B-73-0038, related to the pressure 
transducer, until the PSS unit has accumulated 15 hours or more of 
electrical power within the previous 90 days; or
    (ii) Before further flight, apply electrical power to the PSS 
unit in accordance with the Accomplishment Instructions, paragraph 
5.A.(3)(a)1, of SB LEAP-1B-73-0038, until the PSS unit has 
accumulated 15 hours or more of electrical power within the past 90 
days.
    (2) For an engine in service on the effective date of this AD 
that has accumulated 15 hours or more of electrical power applied to 
the PSS unit within the previous 90 days, within 5 flight cycles of 
the effective date of this AD, perform a one-time check for the 
maintenance messages listed in the Accomplishment Instructions, 
paragraph 5.B.(2)(a)2, of SB LEAP-1B-73-0038, related to the 
pressure transducer.
    (3) For an engine not in service on the effective date of this 
AD that has accumulated fewer than 15 hours of electrical power 
applied to the PSS unit within the past 90 days, before further 
flight, apply electrical power to the PSS unit in accordance with 
the Accomplishment Instructions, paragraph 5.A.(3)(a)1, of SB LEAP-
1B-73-0038, until the PSS unit has accumulated 15 hours or more of 
electrical power within the previous 90 days.
    (4) For an engine not in service on the effective date of this 
AD that has accumulated 15 hours or more of electrical power applied 
to the PSS unit within the previous 90 days, before further flight, 
perform a check for the engine maintenance messages using the 
Accomplishment Instructions, paragraphs 5.A.(3)(b)1 through 5, of SB 
LEAP-1B-73-0038, related to the pressure transducer.
    (5) After accumulating 15 hours of electrical power on the PSS 
unit as required by paragraph (g)(1)(ii) or (g)(3) of this AD, 
before further flight, perform a check for the engine maintenance 
messages using the Accomplishment Instructions, paragraphs 
5.A.(3)(b)1 through 5, of SB LEAP-1B-73-0038, related to the 
pressure transducer.
    (6) If any engine maintenance messages are found by the checks 
required by paragraph (g)(1)(i), (2), (4), or (5) of this AD, before 
further flight, replace the PSS unit with a PSS unit eligible for 
installation.

(h) Definitions

    (1) For the purpose of this AD, an ``in service'' engine is any 
of the following:
    (i) An engine installed on an airplane that was delivered prior 
to November 18, 2020, that, as of the effective date of this AD, has 
completed the Operational Readiness Flight in accordance with 
paragraph (m) of FAA AD 2020-24-02 (85 FR 74560, November 20, 2020); 
or
    (ii) An engine installed on an airplane delivered after November 
18, 2020.
    (2) For the purpose of this AD, hours of electrical power on the 
PSS unit is the total amount of time that voltage was applied to the 
PSS unit either on-wing or on a bench in segments of no less than 15 
minutes. If the voltage-time is not available, use the run time of 
the engine on which the PSS unit is installed.
    (3) For the purpose of this AD, a ``PSS unit eligible for 
installation'' is any of the following:
    (i) A PSS unit that is cleared in accordance with the criteria 
in the Accomplishment Instructions, paragraph 5.B.(3), of SB LEAP-
1B-73-0038; or
    (ii) A PSS unit with an S/N not listed in Additional 
Information, Paragraph 6.A. Table 1 of SB LEAP-1B-73-0038.

(i) Installation Prohibition

    After the effective date of this AD, do not install on any 
engine a PSS unit unless it is a PSS unit eligible for installation 
as defined in paragraph (h)(3) of this AD.

(j) Credit for Previous Actions

    You may take credit for the actions required by paragraphs 
(g)(1)(ii) and (g)(2) through (6) of this AD if you performed these 
actions before the effective date of this AD using CFM SB LEAP-1B-
73-00-0038-01A-930A-D, Issue 001, dated 2021-04-23.

(k) Special Flight Permit

    A special flight permit may be issued in accordance with 14 CFR 
21.197 and 21.199 to operate the airplane for up to 5 flight cycles 
prior to accomplishing paragraph (g)(3) of this AD provided engine 
maintenance messages are checked prior to each flight using the 
Accomplishment Instructions, paragraphs 5.A.(3)(b)1-5, of SB LEAP-1B 
73-0038, and no engine maintenance messages listed in the 
Accomplishment Instructions, paragraph 5.A.(3)(b)5, of SB LEAP-1B-
73-0038, are detected. For all other requirements, special flight 
permits are prohibited.

(l) 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.

(m) Related Information

    For more information about this AD, contact Mehdi Lamnyi, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781) 238-7743; fax: (781) 238-7199; 
email: [email protected].

(n) 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) CFM Service Bulletin (SB) LEAP-1B-73-00-0038-01A-930A-D, 
Issue 002-00, dated 2021-04-25, excluding FADEC Alliance SB LEAP-1B/
73-012, Issue 001, dated 2021-04-23 (which is attached to this CFM 
SB).
    (ii) [Reserved]
    (3) For CFM International, S.A. service information identified 
in this AD, contact CFM International, S.A., Aviation Operations 
Center, 1 Neumann Way, M/D Room 285, Cincinnati, OH 45125; phone: 
(877) 432-3272; fax: (877) 432-3329; email: 
[email protected].
    (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 (781) 238-7759.
    (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: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on April 28, 2021.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2021-09507 Filed 4-30-21; 4:15 pm]
BILLING CODE 4910-13-P

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