[Federal Register Volume 89, Number 145 (Monday, July 29, 2024)]
[Proposed Rules]
[Pages 60836-60838]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-16474]


 ========================================================================
 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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 

  Federal Register / Vol. 89, No. 145 / Monday, July 29, 2024 / 
Proposed Rules  

[[Page 60836]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-1897; Project Identifier AD-2023-00774-T]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain The Boeing Company Model 737-300 and -400 series airplanes. 
This proposed AD was prompted by a report that flight control rigging 
tolerances could result in spoiler deflection not reaching the minimal 
level required to engage the cruise thrust split monitor (MONFD) used 
by the autothrottle (A/T) system. This proposed AD would require 
changing certain wire bundles, installing a new housing assembly, 
removing the mechanical aileron force limiter (MAFL), doing an 
inspection or records check to determine if certain flight control 
computers (FCCs) are installed, and applicable on-condition actions. 
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 September 
12, 2024.

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 under 
Docket No. FAA-2024-1897; 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 material identified in this NPRM, contact Boeing 
Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 
2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; 
telephone 562-797-1717; website myboeingfleet.com.
     You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th Street, 
Des Moines, WA. For information on the availability of this material at 
the FAA, call 206-231-3195. It is also available at regulations.gov by 
searching for and locating Docket No. FAA-2024-1897.

FOR FURTHER INFORMATION CONTACT: Eric Igama, Aviation Safety Engineer, 
FAA, 2200 South 216th Street, Des Moines, WA 98198; telephone 562-627-
5388; email [email protected].

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-2024-1897; Project Identifier 
AD-2023-00774-T'' 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 
this 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 Eric 
Igama, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des 
Moines, WA 98198; telephone 562-627-5388; 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 indicating that flight control 
rigging tolerances could result in spoiler deflection not reaching the 
minimal level required to engage the MONFD used by the A/T system. The 
manufacturer reported that the rigging procedure for Boeing Model 737-
300 and -400 series airplanes equipped with a MAFL allows for rigging 
of the autopilot roll authority limit to a minimum of 15 degrees 
control wheel. However, this control wheel position could result in the 
spoiler deflection not reaching the 2.5 degree A/T MONFD activation 
point, which could prevent the A/T MONFD from engaging. This condition, 
if not addressed, could lead to significant throttle split, leading to 
asymmetric thrust and the subsequent lack of autothrottle 
disengagement, which could result in an uncommanded roll and consequent 
loss of control of the airplane, and reduced ability of the flightcrew 
to maintain the safe flight and landing of the airplane.

[[Page 60837]]

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.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 737-22A1399 RB, 
dated April 13, 2023. This material specifies procedures for changing 
certain wire bundles, installing a new housing assembly, removing the 
MAFL, doing an inspection or records check to determine if certain FCCs 
are installed (FCCs that have an electronic aileron limiter (EAL) 
revision), and applicable on-condition actions. On-condition actions 
include installing new FCCs or re-installing kept FCCs (the 
installation includes doing specified tests and applicable corrective 
actions until the tests are passed).
    This material 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 require accomplishing the actions specified 
in the material already described, except for any differences 
identified as exceptions in the regulatory text of this proposed AD. 
For information on the procedures and compliance times, see this 
material at regulations.gov under Docket No. FAA-2024-1897.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 110 airplanes of U.S. registry. The FAA estimates the following 
costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                    Labor cost         Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Wire bundle change, MAFL          Up to 10 work-hours              $0   Up to $850.........  Up to $93,500.
 removal, housing assembly         x $85 per hour =
 installation, and inspection/     up to $850.
 records review.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary on-
condition actions that would be required based on the results of the 
proposed inspection/records review. The agency has no way of 
determining the number of aircraft that might need these on-condition 
actions:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Installation of FCCs.........................  2 work-hours x $85 per hour =            $7,250           $7,420
                                                $170.
----------------------------------------------------------------------------------------------------------------

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 this 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

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:

The Boeing Company: Docket No. FAA-2024-1897; Project Identifier AD-
2023-00774-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 12, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-300 and -400 
series airplanes, certificated in any category, as identified in

[[Page 60838]]

Boeing Alert Requirements Bulletin 737-22A1399 RB, dated April 13, 
2023.

(d) Subject

    Air Transport Association (ATA) of America Code 27, Flight 
controls.

(e) Unsafe Condition

    This AD was prompted by a report that flight control rigging 
tolerances could result in spoiler deflection not reaching the 
minimal level required to engage the cruise thrust split monitor 
(MONFD) used by the autothrottle (A/T) system. The FAA is issuing 
this AD to address failure of the spoiler deflection to engage the 
MONFD. The unsafe condition, if not addressed, could lead to 
significant throttle split, leading to asymmetric thrust and the 
subsequent lack of autothrottle disengagement, which could result in 
an uncommanded roll and consequent loss of control of the airplane, 
and reduced ability of the flightcrew to maintain the safe flight 
and landing of the airplane.

(f) Compliance

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

(g) Required Actions

    Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 737-22A1399 RB, dated April 13, 2023, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-22A1399 RB, dated April 13, 2023.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-22A1399, dated April 13, 2023, which is referred to in Boeing 
Alert Requirements Bulletin 737-22A1399 RB, dated April 13, 2023.

(h) Exceptions to Requirements Bulletin Specifications

    Where the Compliance Time columns of the table in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 737-
22A1399 RB, dated April 13, 2023, use the phrase ``the original 
issue date of Requirements Bulletin 737-22A1399 RB,'' this AD 
requires using the effective date of this AD.

(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)(1) 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

    (1) For more information about this AD, contact Eric Igama, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: 562-627-5388; email: [email protected].
    (2) Material identified in this AD that is not incorporated by 
reference is available at the address specified in paragraph (k)(3) 
of this AD.

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference of the material listed in this paragraph 
under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this material as applicable to do the actions 
required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Requirements Bulletin 737-22A1399 RB, dated 
April 13, 2023.
    (ii) [Reserved]
    (3) For the material identified in this AD, contact Boeing 
Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 
2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; 
telephone 562-797-1717; website myboeingfleet.com.
    (4) You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th 
Street, Des Moines, WA. For information on the availability of this 
material at the FAA, call 206-231-3195.
    (5) You may view this material at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on July 23, 2024.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-16474 Filed 7-26-24; 8:45 am]
BILLING CODE 4910-13-P