[4910-13-P]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-1687; Project Identifier AD-2024-00253-T; Amendment 3922771; AD 2024-12-07]
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 The Boeing
Company Model 757-200 airplanes modified by particular supplemental type certificates.
This AD was prompted by reports of cracking in the structure in and around the lavatory
service panel. This AD requires repetitively inspecting the lavatory service panel, access
pan, and attaching structure for cracks; reinforcing the attaching structure; and if
necessary, replacing the access pan or repairing cracked parts. The FAA is issuing this
AD to address the unsafe condition on these products.
DATES: This AD is effective [INSERT DATE 15 DAYS AFTER DATE OF
PUBLICATION IN THE FEDERAL REGISTER].
The Director of the Federal Register approved the incorporation by reference of a
certain publication listed in this AD as of [INSERT DATE 15 DAYS AFTER DATE OF
PUBLICATION IN THE FEDERAL REGISTER].
The FAA must receive comments on this AD by [INSERT DATE 45 DAYS
AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].
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-2024-1687; 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.
Material Incorporated by Reference:
• For Precision Conversions LLC material, contact Precision Conversions LLC,
9800 SW Nimbus Ave, Beaverton, OR 97008; ATTN: Brent VanFossen; phone 503-6013001; email brent.vanfossen@precisionaircraft.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 under Docket No. FAA-2024-1687.
FOR FURTHER INFORMATION CONTACT: Joseph Zuklic, Aviation Safety
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone 206-231-3858;
email joseph.r.zuklic@faa.gov.

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 the ADDRESSES section.
Include Docket No. FAA-2024-1687 and Project Identifier AD-2024-00253-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 Joseph Zuklic, Aviation
Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone 206231-3858; email joseph.r.zuklic@faa.gov. 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 several reports of cracking in the structure in and around
the lavatory service panel. The stress concentrations in the lavatory service panel access
pan, the fuselage skin, and the stringer 22 (S-22R) attachment to the service panel are too
high causing fatigue cracking. This condition, if not addressed, could result in an in-flight
depressurization of the airplane, and reduced structural integrity of the aircraft. 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 Material under 1 CFR Part 51
The FAA reviewed Precision Conversions LLC Service Bulletin PC-75753A0005, Revision 2, dated May 7, 2024. This material specifies procedures for a
detailed visual and eddy current inspection of the lavatory service panel, access pan, and
attaching structure for cracks. In addition, this material specifies procedures for
reinforcing the attaching structure including the following repetitive inspections for
cracks: repetitive detailed visual inspections of access pan corners; internal lowfrequency eddy current (LFEC) inspections of the external skin around all fastener holes
common to the access pan; and internal high-frequency eddy current (HFEC) or external
LFEC inspections of the doubler-to-skin fastener holes, skin trim area, and lavatory
service panel cover plate fastener holes. Corrective actions specified in this material
include replacing the access pan and obtaining and following repair instructions, if
necessary. 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.
AD Requirements
This AD requires accomplishing the actions specified in the material already
described, except as discussed under “Differences Between this AD and the Referenced
Material,” and except for any differences identified as exceptions in the regulatory text of
this AD.
Difference Between this AD and the Referenced Material
Precision Conversions Service Bulletin PC-757-53A0005, Revision 2, dated
May 7, 2024, allows repetitive inspections as an option if no crack is found during the
detailed visual inspection of the lavatory service panel, access pan fastener holes, S-22R
stringer, and external skin (Condition 2, Option 1). However, the FAA received
numerous reports of cracking in the structure in and around the lavatory service panel,
necessitating reinforcement of the area within 2,000 flight cycles. Long-term inspections
may not provide the degree of safety necessary for the affected fleet; thus, this AD does
not allow for this inspection to be repeated and instead requires installing the
reinforcement within 2,000 flight cycles after the initial inspection.
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 fatigue cracking in the lavatory service panel, the fuselage
skin, and/or stringer 22 could result in an in-flight depressurization of the airplane and
reduced structural integrity of the aircraft. Several affected airplanes have already
exceeded the flight cycle inspection threshold. In addition, the FAA received numerous
reports of cracking in the structure in and around the lavatory service panel, supporting
an increased likelihood of a decompression event on aircraft that are not reinforced.
Because of the urgency of the unsafe condition, affected airplanes must be inspected
within the grace period (3 months) allowed after the effective date of this AD.
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).
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 13 airplanes of U.S. registry. The FAA
estimates the following costs to comply with this AD:
Estimated costs
Parts cost

Cost per
product

Cost on U.S.
operators

Inspection

8 work-hours X $85
per hour = $680 per
inspection cycle

$0

$680 per
inspection
cycle

$8,840 per
inspection
cycle

Reinforcement
installation

38 work-hours X
$85 per hour =
$3,230

$3,910

$7,140

$92,820

Action

Labor cost

The FAA estimates the following costs to do any replacement that would be
required based on the results of the inspection. The FAA has no way of determining the
number of aircraft that might need this replacement:
On-condition costs
Action

Labor cost

Parts cost

Cost per product

Service pan
replacement

10 work-hours X $85
per hour = $850

$250

$1,100

The FAA has received no definitive data on which to base the cost estimates for
the on-condition repairs specified in this 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
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
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
§ 39.13 [Amended]
2. The FAA amends § 39.13 by adding the following new airworthiness directive:
2024-12-07 The Boeing Company: Amendment 39-22771; Docket No. FAA-20241687; Project Identifier AD-2024-00253-T.
(a) Effective Date
This airworthiness directive (AD) is effective [INSERT DATE 15 DAYS AFTER
DATE OF PUBLICATION IN THE FEDERAL REGISTER].
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company Model 757-200 airplanes, certificated in
any category, modified by supplemental type certificate ST01529SE or ST02278SE.
(d) Subject
Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition
This AD was prompted by reports of cracking in the structure in and around the
lavatory service panel. The FAA is issuing this AD to address cracks in and around the
lavatory service panel. The unsafe condition, if not addressed, could result in an in-flight
depressurization of the airplane and reduced structural integrity of the aircraft.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Requirements
Except as specified in paragraph (h) of this AD: Comply with all required actions
and compliance times specified in, and in accordance with the Accomplishment
Instructions of Precision Conversions Service Bulletin PC-757-53A0005, Revision 2,
dated May 7, 2024.
(h) Exceptions to Service Information Specifications
(1) Where the table in the “Compliance” paragraph of Precision Conversions
Service Bulletin PC-757-53A0005, Revision 2, dated May 7, 2024, refers to the original
issue date of this service bulletin, this AD requires using the effective date of this AD.
(2) Where the table in the “Compliance” paragraph of Precision Conversions
Service Bulletin PC-757-53A0005, Revision 2, dated May 7, 2024, specifies in Condition
2 Option 1 to repetitively inspect if no cracks are found, this AD does not allow repetitive
inspections and requires installing reinforcement within 2,000 flight cycles after the
initial inspection in accordance with Paragraph III, Part 3, Reinforcement, of Precision
Conversions Service Bulletin PC-757-53A0005, Revision 2, dated May 7, 2024.
(3) Where Precision Conversions Service Bulletin PC-757-53A0005, Revision 2,
dated May 7, 2024, specifies contacting Precision Engineering for instructions when
specific conditions are found, this AD requires complying with those instructions by

using a method approved in accordance with the procedures specified in paragraph (i) of
this AD.
(i) Alternative Methods of Compliance (AMOCs)
(1) The Manager, West Certification 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: AMOC@faa.gov.
(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.
(4) Except as required by paragraph (h) of this AD: For material that contains
steps that are labeled as Required for Compliance (RC), the provisions of paragraphs
(i)(4)(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.
(j) Related Information
For more information about this AD, contact Joseph Zuklic, Aviation Safety
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone 206-231-3858;
email joseph.r.zuklic@faa.gov.
(k) 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 material as applicable to do the actions required by this AD,
unless the AD specifies otherwise.
(i) Precision Conversions Service Bulletin PC-757-53A0005, Revision 2, dated
May 7, 2024.
(ii) [Reserved]
(3) For Precision Conversions LLC material, contact Precision Conversions LLC,
9800 SW Nimbus Ave, Beaverton, OR 97008; ATTN: Brent VanFossen; phone
503-601-3001; email brent.vanfossen@precisionaircraft.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
fr.inspection@nara.gov.
Issued on June 11, 2024.

Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2024-13936 Filed: 6/21/2024 11:15 am; Publication Date: 6/26/2024]