Document ID: FAA-2023-1650-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2023-08-10T04:00Z

[Federal Register Volume 88, Number 153 (Thursday, August 10, 2023)]
[Rules and Regulations]
[Pages 54223-54225]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-17197]

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 Rules and Regulations
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  Federal Register / Vol. 88, No. 153 / Thursday, August 10, 2023 / 
Rules and Regulations  

[[Page 54223]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1650; Project Identifier AD-2023-00795-T; 
Amendment 39-22517; AD 2023-15-05]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
The Boeing Company Model 737 airplanes equipped with CFM International, 
S.A. (CFM) Model LEAP-1B series turbofan engines. This AD was prompted 
by a report indicating that use of engine anti-ice (EAI) in dry air for 
more than five minutes during certain environmental and operational 
conditions can cause overheating of the engine inlet inner barrel 
beyond the material design limit, resulting in failure of the engine 
inlet inner barrel and severe engine inlet cowl damage. This AD 
requires revising the existing airplane flight manual (AFM) to limit 
the use of EAI in certain conditions and revising the operator's 
existing minimum equipment list to prohibit dispatch under a certain 
item. The FAA is issuing this AD to address the unsafe condition on 
these products.

DATES: This AD is effective August 25, 2023.
    The FAA must receive comments on this AD by September 25, 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-2023-1650; 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 Docket 
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: James Laubaugh, Aviation Safety 
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3622; email: [email protected].

SUPPLEMENTARY INFORMATION: 

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-2023-1650 and Project Identifier AD-
2023-00795-T 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 
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 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 James 
Laubaugh, Aviation Safety Engineer, FAA, 2200 South 216th St., Des 
Moines, WA 98198; phone: 206-231-3622; email: [email protected]. 
Any commentary that the FAA receives that is not specifically 
designated as CBI will be placed in the public docket for this 
rulemaking.

Background

    The FAA has received a report in June 2023 indicating that flight 
testing and analysis revealed that the use of EAI in dry air for more 
than five minutes during certain combinations of altitude, total air 
temperature, and N1 settings can result in engine inlet cowl 
temperatures exceeding design limits when not in visible moisture. 
Excessive heat buildup can cause overheat of the engine inlet inner 
barrel beyond the material design limit, resulting in failure of the 
engine inlet inner barrel and severe engine inlet cowl damage. There 
have been no reports of in-service failures of the engine inlet inner 
barrel to date.
    This condition as previously described, if not addressed, could 
result in departure of the inlet and potential fan cowl failure and 
departure from the airplane. The departure of the inlet may cause 
fuselage and/or window damage, potentially resulting in decompression 
and hazard to window-seated passengers aft of the wing and/or impact 
damage to the wing, flight control surfaces, and/or empennage, which 
could result in loss of control of the airplane. Inlet loss also causes 
significantly increased aerodynamic drag and asymmetric lift due to 
wing blanking, which risks fuel exhaustion on certain flights, 
resulting in a forced off-airport landing and injury to passengers. The 
FAA is issuing this AD to address the unsafe condition on these 
products.

[[Page 54224]]

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.

AD Requirements

    This AD requires revising the existing AFM to limit the use of 
engine anti-ice in certain conditions. This AD also requires revising 
the operator's existing minimum equipment list (MEL) to prohibit 
dispatch under Master Minimum Equipment List (MMEL) Item 30-21-01B (EAI 
valve locked open). Further analysis of this item is necessary to 
determine whether continued use will cause failure of the engine inlet 
inner barrel.

Compliance With AFM Revision

    Section 91.9 prohibits any person from operating a civil aircraft 
without complying with the operating limitations specified in the AFM. 
FAA regulations also require operators to furnish pilots with any 
changes to the AFM (14 CFR 121.137) and pilots in command to be 
familiar with the AFM (14 CFR 91.505).

MMEL Revision

    This AD refers to Item 30-21-01B (Engine (Cowl) Anti-Ice Valves), 
Boeing 737 MAX (B-737-7/-8/-8200/-9) MMEL, Revision 5, dated June 3, 
2022; this item is also included in an operator's FAA-approved minimum 
equipment list (MEL). This AD prohibits dispatch or release of the 
airplane under conditions currently allowed by that item in the MMEL. 
The FAA plans to revise the MMEL to remove that item in a future 
revision; operators would then be required to also remove that item 
from their existing FAA-approved MEL.

Interim Action

    The FAA considers this AD to be an interim action. The manufacturer 
is currently developing a modification that will address the unsafe 
condition identified in this AD. Once this modification is developed, 
approved, and available, the FAA might consider additional rulemaking.

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 forgoing notice and comment prior to adoption of this rule 
because operating EAI in dry air for more than five minutes during 
certain environmental and operational conditions can cause overheating 
of the engine inlet inner barrel beyond the material design limit, 
resulting in failure of the engine inlet inner barrel and severe engine 
inlet cowl damage. If not addressed, this could result in departure of 
the inlet and potential fan cowl failure and departure from the 
airplane. The departure of the inlet may cause fuselage and/or window 
damage, potentially resulting in decompression and hazard to window-
seated passengers aft of the wing and/or impact damage to the wing, 
flight control surfaces, and/or empennage, which could result in loss 
of control of the airplane. Further, inlet loss causes significantly 
increased aerodynamic drag and asymmetric lift due to wing blanking, 
which risks fuel exhaustion on certain flights, resulting in a forced 
off-airport landing and injury to passengers. 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 forgo notice and 
comment.

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 the FAA has determined 
that it has good cause to adopt this rule without notice and comment, 
RFA analysis is not required.

Costs of Compliance

    The FAA estimates that this AD affects 402 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
----------------------------------------------------------------------------------------------------------------
AFM/MEL revision....................  1 work-hour x $85 per                $0              $85          $34,170
                                       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

    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.

[[Page 54225]]

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:

2023-15-05 The Boeing Company: Amendment 39-22517; Docket No. FAA-
2023-1650; Project Identifier AD-2023-00795-T.

(a) Effective Date

    This airworthiness directive (AD) is effective August 25, 2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737 airplanes 
equipped with CFM International, S.A. (CFM) Model LEAP-1B series 
turbofan engines, certificated in any category.

(d) Subject

    Air Transport Association (ATA) of America Code 30, Ice and Rain 
Protection; 71, Powerplant.

(e) Unsafe Condition

    This AD was prompted by a report indicating that use of engine 
anti-ice (EAI) in dry air for more than five minutes during certain 
environmental and operational conditions can cause overheating of 
the engine inlet inner barrel beyond the material design limit, 
resulting in failure of the engine inlet inner barrel and severe 
engine inlet cowl damage. The FAA is issuing this AD to address use 
of EAI in certain environmental and operational conditions. The 
unsafe condition, if not addressed, could result in departure of the 
inlet and potential fan cowl failure and departure from the 
airplane. The departure of the inlet may cause fuselage and/or 
window damage, potentially resulting in decompression and hazard to 
window-seated passengers aft of the wing and/or impact damage to the 
wing, flight control surfaces, and/or empennage, which could result 
in loss of control of the airplane. Inlet loss also causes 
significantly increased aerodynamic drag and asymmetric lift due to 
wing blanking, which risks fuel exhaustion on certain flights, 
resulting in a forced off-airport landing and injury to passengers.

(f) Compliance

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

(g) Airplane Flight Manual (AFM) Revision

    Within 15 days after the effective date of this AD: Revise the 
Limitations Section of the existing AFM to include the information 
specified in figure 1 to paragraph (g) of this AD. This may be done 
by inserting a copy of figure 1 to paragraph (g) of this AD into the 
existing AFM.
[GRAPHIC] [TIFF OMITTED] TR10AU23.010

(h) Minimum Equipment List (MEL) Revision

    Within 15 days after the effective date of this AD or upon 
completion of the AFM revision required by paragraph (g) of this AD, 
whichever occurs first: Revise the operator's existing FAA-approved 
MEL to prohibit dispatch under the MEL item corresponding with 
Master Minimum Equipment List (MMEL) Item 30-21-01B (Engine (Cowl) 
Anti-Ice Valves).

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, AIR-520, Continued Operational Safety 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 
responsible Flight Standards 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 (j) 
of this AD. Information may be emailed to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the responsible Flight Standards Office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by The Boeing Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, AIR-
520, Continued Operational Safety Branch, FAA, to make those 
findings. To be approved, the repair method, modification deviation, 
or alteration deviation must meet the certification basis of the 
airplane, and the approval must specifically refer to this AD.

(j) Related Information

    For more information about this AD, contact James Laubaugh, 
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 
98198; phone: 206-231-3622; email: [email protected].

(k) Material Incorporated by Reference

    None.

    Issued on July 31, 2023.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-17197 Filed 8-7-23; 4:15 pm]
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