[Federal Register Volume 90, Number 85 (Monday, May 5, 2025)]
[Proposed Rules]
[Pages 18930-18932]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-07724]


========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

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.

========================================================================


Federal Register / Vol. 90, No. 85 / Monday, May 5, 2025 / Proposed 
Rules

[[Page 18930]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-0744; Project Identifier AD-2024-00586-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 757-200 and -300 series airplanes. 
This proposed AD was prompted by cracking found during an inspection on 
an airplane equipped with Aviation Partners Boeing (APB) scimitar 
blended winglets (SBWs). This proposed AD would require performing a 
general visual inspection (GVI) or maintenance records check of certain 
stringers for an approved freeze plug repair, performing a high 
frequency eddy current (HFEC) inspection of the same area for any crack 
common to a certain stringer and a reinforcement strap, 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 June 20, 
2025.

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-2025-0744; 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 Aviation Partners Boeing material identified in this 
proposed AD, contact Aviation Partners Boeing, 2811 South 102nd St., 
Suite 200, Seattle, WA 98168; telephone 206-830-7699; email 
[email protected]; website aviationpartnersboeing.com.
     You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th St., Des 
Moines, WA. For information on the availability of this material at the 
FAA, call 206-231-3195.

FOR FURTHER INFORMATION CONTACT: Sarah Illg, Aviation Safety Engineer, 
FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone: 206-231-3517; 
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 the ADDRESSES section. Include ``Docket No. FAA-2025-0744; 
Project Identifier AD-2024-00586-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 Sarah 
Illg, Aviation Safety Engineer, FAA, 3960 Paramount Boulevard, 
Lakewood, CA 90712; phone: 206-231-3517; 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 a crack on a Model 757-200 
airplanes equipped with APB scimitar blended winglets found during an 
HFEC inspection during accomplishment of a 4C maintenance check. The 
airplane had 22,185 total flight cycles and 106,470 total flight hours. 
The 0.40-inch crack was found on the right wing lower stringer L-8 
vertical web flange at approximately wing station (WS) 401, located at 
a fastener common to the stringer L-8 and a reinforcement strap. The 
blended winglet configuration on Model 757-200 and -300 airplanes is 
similar; therefore, the 757-300 airplanes are also subject to the 
unsafe condition identified in this NPRM. This condition, if not 
addressed, could result in the inability of a principal structural 
element to sustain limit loads, which could adversely affect the 
structural integrity of the airplane.

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.

[[Page 18931]]

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed Aviation Partners Boeing Service Bulletin AP757-
57-012 Revision 1, dated October 17, 2024. This material specifies 
procedures for performing a GVI or maintenance records check of the 
lower stringer L-6 and lower stringer L-8 vertical web flange, between 
WS 397.50 and WS 403 for an approved freeze plug repair; a surface HFEC 
inspection for cracking of the wing lower stringer L-6 and lower 
stringer L-8 vertical web flange, common to the reinforcement strap 
attach fasteners located between WS 397.50 and WS 403.00; and 
applicable on-condition actions. On-condition actions include 
repetitive surface HFEC inspections for cracking, crack length 
measurement, a surface HFEC inspection of the lower stringer L-6 or L-8 
vertical web flange around each of the four fasteners for cracks, crack 
removal, freeze plug repair, and crack repair.
    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 the ADDRESSES section.

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.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 156 airplanes of U.S. registry. 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
----------------------------------------------------------------------------------------------------------------
Left- and Right-wing GVI and     7 work-hours x              $0  Up to $595............  Up to $92,820.
 HFEC Inspection.                 $85 per hour =
                                  $595.
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition actions specified in this proposed AD.

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-2025-0744; Project Identifier AD-
2024-00586-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by June 20, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 757-200 and -300 
series airplanes, certificated in any category, as specified in 
paragraph 1.A.1 of Aviation Partners Boeing Service Bulletin AP757-
57-012, Revision 1, dated October 17, 2024.

(d) Subject

    Air Transport Association (ATA) of America Code 57, Wings.

(e) Unsafe Condition

    This AD was prompted by an operator reporting a crack on a Model 
757-200 airplane equipped with Aviation Partners Boeing (APB) 
scimitar blended winglets (SBWs). The FAA is issuing this AD to 
address the potential for cracking on the right- or left-wing lower 
stringer L-8 or L-6 vertical web flange at a fastener common to the 
reinforcement strap. The unsafe condition, if not addressed, could 
result in the inability of a principal structural element to sustain 
limit loads, which could adversely affect the structural integrity 
of the airplane.

(f) Compliance

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

(g) Required Actions

    Except as specified in paragraphs (h) and (i) of this AD: At the 
applicable times specified in paragraph 1.E., ``Compliance,'' of 
Aviation Partners Boeing Service Bulletin AP757-57-012, Revision 1, 
dated October 17, 2024, do all applicable actions identified as 
``RC'' (required for compliance) in, and in accordance with, the 
Accomplishment Instructions of Aviation Partners Boeing Service 
Bulletin AP757-57-012, Revision 1, dated October 17, 2024.

(h) Exceptions to Service Bulletin Specifications

    (1) Where the Compliance Time columns of the tables in 
``Compliance'' paragraph of

[[Page 18932]]

Aviation Partners Boeing Service Bulletin AP757-57-012, Revision 1, 
dated October 17, 2024, refer to ``the original issue date of this 
Service Bulletin,'' this AD requires using the effective date of 
this AD.
    (2) Where Table 2 and Table 3 of the ``Compliance'' paragraph of 
Aviation Partners Boeing Service Bulletin AP757-57-012, Revision 1, 
dated October 17, 2024, specify Action 1 without a compliance time, 
for this AD, the compliance time is before 9,500 flight cycles after 
the blended winglet installation, within 3,000 flight cycles after 
the effective date of this AD, or within 24 months after the 
effective date of this AD, whichever occurs latest.
    (3) Where Table 5 and Table 6 of the ``Compliance'' paragraph of 
Aviation Partners Boeing Service Bulletin AP757-57-012, Revision 1, 
dated October 17, 2024, specify Action 1 without a compliance time, 
for this AD, the compliance time is before 8,000 flight cycles after 
the blended winglet installation, within 3,000 flight cycles after 
the effective date of this AD, or within 24 months after the 
effective date of this AD, whichever occurs latest.
    (4) Where Table 9 and Table 10 of the ``Compliance'' paragraph 
of Aviation Partners Boeing Service Bulletin AP757-57-012, Revision 
1, dated October 17, 2024, specify Action 1 without a compliance 
time, for this AD, the compliance time is before 9,500 flight cycles 
after the blended winglet installation, within 3,000 flight cycles 
after the effective date of this AD, or within 22 months after the 
effective date of this AD, whichever occurs latest.
    (5) Where Table 12 and Table 13 of the ``Compliance'' paragraph 
of Aviation Partners Boeing Service Bulletin AP757-57-012, Revision 
1, dated October 17, 2024, specify Action 1 without a compliance 
time, for this AD, the compliance time is before 8,000 flight cycles 
after the blended winglet installation, within 3,000 flight cycles 
after the effective date of this AD, or 22 within months after the 
effective date of this AD, whichever occurs latest.
    (6) Where flagnote (b) of Figure 5 and Figure 10 of the 
Accomplishment Instructions of Aviation Partners Boeing Service 
Bulletin AP757-57-012, Revision 1, dated October 17, 2024, specifies 
``If the crack is less than or equal to 0.268 inch, remove the 
crack. Refer to 757-200 SRM 51-10-02 as an accepted procedure. 
Maximum hole diameter 0.80 inch,'' for this AD, replace that text 
with ``If the crack is less than or equal to 0.268 inch, remove the 
crack. Refer to 757-200 SRM 51-10-02 as an accepted procedure. 
Maximum hole diameter 0.80 inch. Do an open-hole HFEC inspection of 
the hole in the stringer in accordance with 757 NDT Manual Part 6, 
51-00-04, 51-00-11, or 51-00-16.''
    (7) Where Condition 2 of Table 6 in the Accomplishment 
Instructions of Aviation partners Boeing Service Bulletin AP757-57-
012, Revision 1, dated October 17, 2024, includes ``remove crack'' 
as part of the actions, the action ``remove crack'' is not required 
by this AD for Condition 2 of Table 6.
    (8) Where Action 2 of Condition 4.2 in Table 3 of the 
Accomplishment Instructions of Aviation Partners Boeing Service 
Bulletin AP757-57-012, Revision 1, dated October 17, 2024, does not 
include a method of compliance for the inspection, for this AD, the 
method of compliance is Figure 3 of the Accomplishment Instructions 
of Aviation Partners Boeing Service Bulletin AP757-57-012, Revision 
1, dated October 17, 2024.
    (9) Where Action 2 of Condition 4.2 in Table 6 of the 
Accomplishment Instructions of Aviation Partners Boeing Service 
Bulletin AP757-57-012, Revision 1, dated October 17, 2024, does not 
include a method of compliance for the inspection, for this AD, the 
method of compliance is Figure 8 of the Accomplishment Instructions 
of Aviation Partners Boeing Service Bulletin AP757-57-012, Revision 
1, dated October 17, 2024.
    (10) Where Aviation Partners Boeing Service Bulletin AP757-57-
012, Revision 1, dated October 17, 2024, specifies contacting 
Aviation Partners Boeing for repair instructions: This AD requires 
repair using a method approved in accordance with the procedures 
specified in paragraph (j) of this AD.

(i) No Report

    Although Aviation Partners Boeing Service Bulletin AP757-57-012, 
Revision 1, dated October 17, 2024, specifies to report existing 
repairs, this AD does not require any report.

(j) 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 (k) 
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) Except as specified by paragraph (g) of this AD: For 
material that contains steps that are labeled as Required for 
Compliance (RC), the provisions of paragraphs (j)(3)(i) and (ii) of 
this AD apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. If a step or substep is labeled ``RC Exempt,'' then the 
RC requirement is removed from that step or substep. An AMOC is 
required for any deviations to RC steps, including substeps and 
identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(k) Related Information

    For more information about this AD, contact Sarah Illg, Aviation 
Safety Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; 
phone: 206-231-3517; email: [email protected].

(l) 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) Aviation Partners Boeing Service Bulletin AP757-57-012, 
Revision 1, dated October 17, 2024.
    (ii) [Reserved]
    (3) For Aviation Partners Boeing material identified in this AD, 
contact Aviation Partners Boeing, 2811 South 102nd St., Suite 200, 
Seattle, WA 98168; telephone 206-830-7699; email 
[email protected]; website aviationpartnersboeing.com.
    (4) You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th St., 
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 April 24, 2025.
Victor Wicklund,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-07724 Filed 5-2-25; 8:45 am]
BILLING CODE 4910-13-P