[4910-13-P]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2023-2003; Project Identifier AD-2022-01620-T; Amendment 3922750; AD 2024-10-05]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD) for certain The
Boeing Company Model 757 airplanes. This AD was prompted by reports of operators
finding frequent and severe damage to the blowout vent grilles throughout the lower lobe
cargo compartment. This AD requires repetitive detailed inspections of certain
decompression panels and pressure equalization valves, as applicable, in the forward and
aft lower lobe cargo compartments for damage, and applicable on-condition actions. For
certain airplanes, this AD also requires installation of decompression panels with billet
grilles. For other certain airplanes, this AD also requires replacement of a certain soft
bulkhead with a rigid bulkhead. For certain other airplanes, this AD requires installation
of doublers to a certain bulkhead assembly panel. The FAA is issuing this AD to address
the unsafe condition on these products.
DATES: This AD is effective [INSERT DATE 35 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 35 DAYS AFTER DATE OF
PUBLICATION IN THE FEDERAL REGISTER].

ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA2023-2003; 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 address for Docket Operations is U.S.
Department of Transportation, Docket Operations, M-30, West Building Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
Material Incorporated by Reference:
• For service information, 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 service information 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. It is also
available at regulations.gov under Docket No. FAA-2023-2003.
FOR FURTHER INFORMATION CONTACT: Katherine Venegas, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone: 562-6275353; email: Katherine.Venegas@faa.gov.
SUPPLEMENTARY INFORMATION:
Background
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 by adding an AD that would apply to certain The Boeing Company Model 757
airplanes. The NPRM published in the Federal Register on October 26, 2023 (88 FR
73543). The NPRM was prompted by reports of operators finding frequent and severe
damage to the blowout vent grilles throughout the lower lobe cargo compartment. In the
NPRM, the FAA proposed to require repetitive detailed inspections of certain

decompression panels and pressure equalization valves, as applicable, in the forward and
aft lower lobe cargo compartments for damage, and applicable on-condition actions. For
certain airplanes, the FAA proposed to require replacement of a certain soft bulkhead
with a rigid bulkhead. For certain other airplanes, the FAA proposed to require
installation of doublers to a certain bulkhead assembly panel. The FAA is issuing this AD
to address damage to the blowout vent grilles in the forward and aft lower lobe cargo
compartments that could lead to latent failure of the decompression panels and pressure
equalization valves. This latent failure, in combination with a fire, could make the cargo
fire protection, detection, suppression, and containment system ineffective. Also, this
latent failure, in combination with rapid decompression of the airplane, could prevent
activation of the station (STA) 1640 decompression panels, which could damage the STA
1640 floor beam and cause loss of hydraulic systems components and flight control and
damage to the auxiliary power unit (APU) fuel line. This unsafe condition, if not
addressed, could result in the inability of the flightcrew to maintain safe flight and
landing.
Discussion of Final Airworthiness Directive
Comments
The FAA received a comment from Air Line Pilots Association, International
who supported the NPRM without change. The FAA received additional comments from
Airlines for America (A4A), Aviation Partners Boeing, Boeing, Delta Air Lines,
European Air Transport Leipzig GmbH, FedEx Express, United Airlines, and United
Parcel Service (UPS) Airlines. The following presents the comments received on the
NPRM and the FAA’s response to each comment.

Effect of Winglets on Accomplishment of the Proposed Actions
Aviation Partners Boeing stated that the installation of winglets per Supplemental
Type Certificate (STC) ST01518SE does not affect the accomplishment of the
manufacturer’s service instructions.
The FAA agrees with the commenter that STC ST01518SE does not affect the
accomplishment of the manufacturer’s service instructions. Therefore, the installation of
STC ST01518SE does not affect the ability to accomplish the actions required by this
AD. The FAA has not changed this AD in this regard.
Request to Correct Typographical Error
Boeing requested that the word “grill” be replaced with “grille” throughout the
NPRM. Boeing stated grille is consistent with the service information and is the accurate
spelling, which means a screen of metal bars or wires placed in front of something as
protection or to allow ventilation.
The FAA agrees with the change and has revised this final rule accordingly.
Request to Clarify the Service History, Unsafe Condition, and Required Actions
Boeing requested the NPRM be revised to clarify the service history, unsafe
condition, and required actions. Regarding the service history, Boeing clarified that
reported damage was not limited to the STA 1640 soft bulkhead lining only; operators
reported finding damage on the decompression panels throughout the lower lobe cargo
compartment. Boeing also clarified that undetected damage in combination with a cargo
compartment fire or rapid depressurization could prevent continued safe flight and
landing. Boeing stated that damaged lower lobe decompression panels can diminish the
capabilities of the cargo fire protection, detection, suppression, and containment system.
Boeing further stated failure of a decompression panel at STA 1640 in combination with
a decompression event could cause damage to the bulkhead components including
hydraulic systems, flight control functions, and the APU fuel line. Regarding the required

actions, Boeing clarified that required actions include, at a minimum, repetitive
inspections of lower lobe decompression panels, installation of protective grilles, and for
certain airplanes installation of a rigid bulkhead. Boeing is requesting these changes to
improve accuracy and consistency with the service information.
The FAA agrees to clarify the service history, required actions, and unsafe
condition in this final rule: The FAA revised the Summary, Background, and Unsafe
Condition paragraphs of this final rule to clarify that operators found frequent and severe
damage to the blowout vent grilles throughout the lower lobe cargo compartment. The
FAA also revised the Background and Unsafe Condition paragraphs of this final rule to
clarify that failure of a STA 1640 decompression panel in combination with rapid
decompression of the airplane could also cause damage APU fuel line. Further, the FAA
revised the Summary and Related Service Information Under 1 CFR Part 51 paragraphs
to clarify that this final rule requires, for certain airplanes, installation of decompression
panels with billet grilles on the bulkheads and sidewalls of the forward and aft lower lobe
cargo compartments and installation of decompression panels on the ceilings of the
forward and aft lower lobe cargo compartments. In the NPRM, the FAA included the cost
of installing the decompression panels with the inspection cost. Therefore, the FAA has
revised the estimated costs in this final rule by breaking out those costs as separate line
items.
Request to Exclude Cargo/Freighter Airplanes from the NPRM
A4A, FedEx Express, and UPS Airlines requested that cargo/freighter airplanes
be excluded from the applicability of the NPRM. The commenters stated cargo operators
experience different in-service issues than passenger operators because cargo operators
have lower flight hour and flight cycle utilization rates and generally ship smaller and
lighter packages in the lower cargo area. The commenters also stated they possess
historical data and operational experience that support excluding cargo/freighter

airplanes. A4A stated its affected members (Delta Air Lines, FedEx Express, United
Airlines, and UPS Airlines) have recorded and documented only insignificant damage to
the subject area. Specifically, FedEx reviewed the maintenance data of its Boeing Model
757 fleet over a 15-year period and stated it did not find a single report of a malfunction
or damage that would diminish the capabilities of the forward and aft cargo fire
protection, detection, suppression, or containment system. UPS Airlines also reviewed its
Boeing Model 757 fleet records since 1987 and found 26 grille replacements across all
300 locations. The commenters added that Boeing fleet team digest 757-FTD-25-19003
stated the following: “At this time no incidents have been reported on a latent failure to a
decompression panel failing to open or having diminished performance during a rapid
decompression event. There have also been no reports of a dislodged decompression
panel resulting in diminished functionality of the fire containment, detection or
suppression systems.”
UPS Airlines stated the risk assessment of the unsafe condition included impacts
to fire suppression in the lower cargo components, which does not affect its fleet of
Boeing Model 757-200PF airplanes because that airplane model was certified with
Class E cargo compartments without fire suppression. For this reason, UPS Airlines
concluded that damage to the protective grilles on its freighter airplanes (Group 6 in the
service information) will not have the same impact as damage to passenger airplanes.
UPS Airlines further stated its freighter airplanes do not have decompression panels at
the STA 1640 bulkhead and do not require reinforcement according to the service
information. UPS Airlines therefore concluded any risk associated with damage to the
STA 1640 floor beam and adjacent flight controls and hydraulic systems would not affect
its fleet.
The FAA does not agree to exclude cargo/freighter airplanes from the
applicability of this AD. The FAA acknowledges cargo operators have different

in-service issues than passenger operators, and that cargo operators may have lower
utilization rates and different cargo contents. However, the manufacturer evaluated all
type design configurations including passenger, freighter, and converted freighter
airplanes, and the data available indicated similar damage for containerized cargo and
bulk cargo. Sufficient data was not submitted by the commenters to substantiate that
excluding cargo airplanes would provide an acceptable level of safety. However, under
the provisions of paragraph (i) of this AD, the FAA will consider requests for approval of
alternative actions and compliance times if sufficient data are submitted to substantiate
that the change would provide an acceptable level of safety.
Request to Require Repetitive Inspection Instead of Modification
A4A, FedEx Express, and UPS Airlines requested that a repetitive inspection
program be implemented for cargo/freighter airplanes instead of the proposed
modification (i.e., replacement of protective grilles with new billet grilles) if these
airplanes are not excluded from the applicability of the NPRM. A4A also made the same
request for passenger-carrying airplanes. United Airlines and Delta Air Lines similarly
requested the NPRM be revised to require only initial and repetitive inspections in lieu of
modification. As justification, United Airlines stated they have communicated with other
affected operators who have indicated similar operating experience of limited or no
damage that would indicate decompression valve failure, and their concern that parts will
not be available to accomplish the modification within the proposed compliance time.
Delta Air Lines stated repetitive inspections in lieu of modification would allow operators
the necessary flexibility to obtain the required materials and would continue to ensure the
integrity of the decompression panels and valves to address the safety concern.
A4A stated that automatic removal of certain existing grilles would be a burden
on operators without additional safety benefits. A4A justified a repetitive inspection
program over modification because an inspection program would allow all operators to

use their existing maintenance programs to identify any potential damage and repair prior
to flight. In addition, FedEx Express stated its employees who load/unload cargo perform
pre- and post-flight checks of the lower cargo decks, and that any damage found would
be repaired prior to flight. FedEx Express also stated, as part of its maintenance program,
a visual inspection of the panels is performed every 7 days. FedEx stated that the service
information underestimates the number of work-hours required to perform the
modification. FedEx also noted the modification would cost over $14.7 million, and that
does not include the cost to replace/repair damaged panels. United Airlines stated the
modification would cost $1.8 million, which does not include the cost of removing
airplanes from service.
UPS Airlines objected to the proposed replacement of existing protective grilles
with a new billet grille regardless of inspection findings, due to the historical data and
documentation of insignificant damage found (as discussed previously). The commenter
concluded, if no damage is found during the proposed inspections, then the grilles are
structurally and functionally acceptable for operating conditions as certified. In addition,
the commenter stated general visual zonal inspections during maintenance program
checks, coupled with pre- and post-flight inspections, will adequately address any
protective grille damage on an attrition basis. The commenter stated replacement of
undamaged grilles is an unnecessary burden on operator resources and provides no
operational or safety benefits, especially for the Boeing Model 757-200PF.
The FAA does not agree to allow implementation of a repetitive inspection
program for cargo- or passenger-carrying airplanes instead of the modification. The FAA
considered more frequent and repetitive inspections and evaluated an interval of
750 flight hours. However, the FAA considered this interval to be an unacceptable
burden to operators. The FAA determined that those inspections would be intrusive and
could cause further damage. The installation of protective grilles with the billet design is

necessary to address the unsafe condition. There is not sufficient data to substantiate that
repetitive inspections alone would provide an acceptable level of safety. However, under
the provisions of paragraph (i) of this AD, the FAA will consider requests for approval of
alternative actions and compliance times if sufficient data are submitted to substantiate
that the change would provide an acceptable level of safety.
Regarding the comments on the costs, the FAA acknowledges the commenters’
concerns about the cost of the modification. The manufacturer provided its best estimate
of the number of work hours necessary to do the required actions. Additionally, the FAA
notes that the cost analysis in AD rulemaking actions typically includes only the costs
associated with complying with the AD, which does not include indirect or incidental
costs such as down-time and loss of revenue or the time necessary for planning or other
administrative actions. Those incidental or indirect costs might vary significantly among
operators.
Request to Extend the Compliance Time for Passenger Airplanes
A4A requested the NPRM be revised to extend the compliance time for the initial
inspection of the decompression panels and modification to 36-48 months for passengercarrying airplanes if the FAA finds a repetitive inspection program unacceptable. United
Airlines also requested the compliance time for the modification be extended to 36-48
months. Delta Air Lines requested the compliance time for the initial inspection and
modification be extended to within 9,000 flight hours or 36 months after the effective
date of the AD. The commenters stated an extension would give the supplier sufficient
time to provide the needed parts to operators and allow operators to accomplish the
requirements of the proposed AD within their normal maintenance schedule during a
heavy maintenance visit, reducing impact to their operations.
The FAA does not agree to extend the compliance time for passenger-carrying
airplanes. In developing an appropriate compliance time for this action, the FAA

considered the recommendations of the manufacturer, the urgency associated with the
subject unsafe condition, the availability of required parts, and the practical aspect of
accomplishing the required modification within a period of time that corresponds to the
normal scheduled maintenance for most affected operators. In consideration of these
items, as well as the reports of damage to grilles and panels, the FAA determined that the
initial compliance time of 5,425 flight hours or 16 months, whichever occurs first, will
ensure an acceptable level of safety. Under the provisions of paragraph (i) of this AD, the
FAA will consider requests for approval of an extension of the compliance time if
sufficient data are submitted to substantiate that new compliance time would provide an
acceptable level of safety.
Request to Extend the Compliance Time for Certain Cargo Airplanes
UPS Airlines requested the NPRM be revised to extend the compliance time for
the initial inspection of the decompression panels to within 9,000 flight hours or
36 months after the effective date of the AD, whichever occurs first, for Boeing Model
757-200PF airplanes (Group 6 in the service information), if the FAA finds a repetitive
inspection program unacceptable. The commenter noted that the service information
states damage could be caused by repeated loading and unloading of the compartments.
The commenter stated cargo operators fly significantly less hours and cycles than
passenger aircraft resulting in a proportional decrease in risk associated with damage to
the decompression panels, and that the commenter’s affected fleet of Boeing Model
757-200PF airplanes currently averages 943 flight hours and 576 flight cycles per year.
Based on this data, the commenter concluded it would take about 69 months for its fleet
to reach the proposed initial inspection threshold of 5,425 flight hours, and that the
proposed flight hour limits are not proportional to the proposed calendar times. The
commenter also noted that the proposed repetitive inspection increases to 9,000 flight
hours (114 months based on its fleet utilization) or 26 months, whichever occurs first.

The commenter stated that, if a repetitive interval of 26 months is adequate to ensure
continued airworthiness, then an initial compliance of 16 months is overly conservative
for a fleet that has been operating for more than 35 years without a decompression panel
failure because of damage.
The FAA agrees to extend the compliance time to within 9,000 flight hours or
36 months after the effective date of this AD, whichever occurs first, for Boeing Model
757-200PF airplanes only. The FAA acknowledges cargo operators have different inservice issues than passenger operators, and cargo operators may have lower utilization
rates. Considering that cargo operators fly less hours and cycles than passenger aircraft,
the FAA has determined the equivalent flight hour and calendar compliance time can be
extended to 9,000 flight hours and 36 months for cargo/freighter operators and still
ensure an acceptable level of safety. Therefore, the FAA has added an exception to
paragraph (h) of this AD to revise the compliance time to within 9,000 flight hours or
within 36 months after the effective date of this AD, whichever occurs first, for Group 6
airplanes.
Request to Extend the Compliance Time to 36-48 Months for All Cargo Airplanes
A4A, FedEx Express, and European Air Transport Leipzig GmbH, on behalf of
DHL Express, requested the NPRM be revised to extend the initial compliance time.
FedEx Express requested the compliance time for the initial inspection of the
decompression panels and modification be extended to 36-48 months for cargo/freight
airplanes if the FAA finds a repetitive inspection program unacceptable. European Air
Transport Leipzig GmbH, on behalf of DHL Express, requested the 16-month
compliance time be extended to 48 months (and the respective 16,275 flight hours) from
the effective of the AD. The commenters stated an extension would give the supplier
sufficient time to provide the needed parts to operators and allow operators to accomplish

the requirements of the proposed AD within their normal maintenance schedule during a
heavy maintenance visit, reducing impact to their operations.
The FAA partially agrees. The FAA does not agree to extend the initial
compliance time to 48 months for cargo/freight airplanes, but the FAA agrees to extend
the compliance time to 36 months. For the reasons discussed previously, the FAA has
added exceptions to paragraph (h) of this AD to extend the compliance time to within
9,000 flight hours or within 36 months after the effective date of this AD, whichever
occurs first, for Groups 1, 2, and 4 airplanes that have been converted from a passenger to
freighter configuration in accordance with VT Mobile Aerospace Engineering (MAE)
Inc. STC ST04242AT or STC ST03562AT or Precision Conversions LLC STC
ST01529SE, and for Group 6 airplanes. Under the provisions of paragraph (i) of this AD,
the FAA will consider requests for approval of an extension of the compliance time if
sufficient data are submitted to substantiate that new compliance time would provide an
acceptable level of safety.
Request to Revise Corrective Action
UPS Airlines requested the FAA revise the NPRM to allow operators the option
of installing either serviceable protective grilles or billet grilles. UPS Airlines objected to
the proposed replacement of existing protective grilles with a new billet grille regardless
of inspection findings, due to the historical data and documentation of insignificant
damage found (as discussed previously). The commenter concluded, if no damage is
found during the proposed inspections, then the grilles are structurally and functionally
acceptable for operating conditions as certified. In addition, the commenter stated that the
supplier does not have the necessary billet grilles in stock to support inspection of two of
its Model 757-200PF airplanes, and the parts supplier has not provided a completion date
for the remaining parts. Based on this, the commenter believes supplier cannot adequately

support the parts needed for the affected worldwide fleet to meet the proposed
compliance time.
The FAA does not agree to allow the installation of serviceable protective grilles
instead of billet grilles. The FAA acknowledges freighter configuration airplanes are
constructed and operated differently than passenger configuration, and that their contents
also differ. However, the FAA has determined that the installation of protective grilles
with the billet design is necessary to address the unsafe condition. There is not sufficient
data to substantiate that the installation of a serviceable protective grille would correct the
unsafe condition. The FAA notes that, as discussed previously, the compliance time for
cargo operators to accomplish the initial inspections and replacements has been extended
in this final rule. Additionally, under the provisions of paragraph (i) of this AD, the FAA
will consider requests for approval of alternative actions and compliance times if
sufficient data are submitted to substantiate that the change would provide an acceptable
level of safety.
Request to Add Additional Requirement for Group 3 Airplanes
Delta Air Lines requested that an exception be added to the NPRM requiring
installation of decompression panels with billet grilles on the bulkheads and sidewall of
the forward and aft lower lobe cargo compartments of Group 3 airplanes before further
flight. The commenter compared the actions in table 4, condition 8, for Group 3 airplanes
and table 6, condition 12, for Group 5 airplanes, and noted table 6 requires installation of
decompression panels with billet grilles but table 4 does not. The commenter believes the
installation should be required for both airplane groups.
The FAA does not agree to revise this final rule. Group 3 airplanes are Boeing
Model 757-300 airplanes that already have decompression panels with billet grilles
installed per type design.

Request to Revise Part Marking Requirement
Delta Air Lines requested that an exception be added to the NPRM stating, where
certain figures require parts to be marked with the service bulletin number, part marking
is only required if not previously marked. The commenter believes the figures that
require part marking apply to the initial and repetitive actions. Based on this, the
commenter stated the parts would need to be marked every time, even if they were
previously marked.
The FAA does not agree to revise this final rule. The figures that specify marking
the part with the service bulletin number are only listed as a method of compliance for the
installation of panels with billet grilles. Those figures are not listed as a method of
compliance for the repetitive actions.
Conclusion
The FAA reviewed the relevant data, considered any comments received, and
determined that air safety requires adopting this AD as proposed. Accordingly, the FAA
is issuing this AD to address the unsafe condition on these products. Except for minor
editorial changes, and any other changes described previously, this AD is adopted as
proposed in the NPRM. None of the changes will increase the economic burden on any
operator.
Related Service Information under 1 CFR Part 51
The FAA reviewed Boeing Alert Requirements Bulletin 757-25A0319 RB, dated
March 24, 2023. This service information specifies procedures for repetitive detailed
inspections of certain bulkhead (including STA 1640), sidewall, ceiling, and E5 EE rack
decompression panels, and pressure equalization valves on certain airplanes, in the
forward and aft lower lobe cargo compartments for damage; and applicable on-condition
actions. On-condition actions include repair or replacement of any damaged
decompression panels or pressure equalization valves. For certain airplanes, the service

information specifies procedures for installing decompression panels with billet grilles on
the bulkheads and sidewalls of the forward and aft lower lobe cargo compartments and
installing decompression panels on the ceilings of the forward and aft lower lobe cargo
compartments, as applicable. For other certain airplanes, this service information also
specifies procedures for replacing the soft bulkhead at STA 1640 with a rigid bulkhead
having decompression panels with billet grilles. For certain other airplanes, this service
information specifies procedures for installing doublers to the bulkhead assembly panel at
STA 1640.
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 the
ADDRESSES section.
Costs of Compliance
The FAA estimates that this AD affects 489 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

Up to 9 work-hours
X $85 per hour =
$765 per inspection
cycle

$0

Up to $765
per
inspection
cycle

Up to
$374,085 per
inspection
cycle

Installation of
decompression
panels (465
airplanes)

Up to 12 work-hours
X $85 per hour =
$1,020

Up to
$22,460

Up to
$23,480

Up to
$10,918,200

Replacement of
soft bulkhead
(100 airplanes)

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

$108,240

$109,090

$10,909,000

Installation of
doublers
(7 airplanes)

2 work-hours X $85
per hour = $170

$1,760

$1,930

$13,510

Action

Labor cost

Detailed
Inspection

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

Labor cost

Parts cost

Cost per product

Repair

12 work-hours X $85
per hour = $1,020

$54,120

$55,140

Replacement

12 work-hour X $85
per hour = $1,020

$108,240

$109,260

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,
(2) Will not affect intrastate aviation in Alaska, and
(3) Will 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 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:
2024-10-05 The Boeing Company: Amendment 39-22750; Docket No. FAA-20232003; Project Identifier AD-2022-01620-T.
(a) Effective Date
This airworthiness directive (AD) is effective [INSERT DATE 35 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, -200PF, -200CB, and
-300 series airplanes, certificated in any category, as identified in Boeing Alert
Requirements Bulletin 757-25A0319 RB, dated March 24, 2023.

(d) Subject
Air Transport Association (ATA) of America Code 25, Equipment/Furnishings.
(e) Unsafe Condition
This AD was prompted by reports that operators have found, on multiple aircraft,
frequent and severe damage to the blowout vent grilles throughout the lower lobe cargo
compartment. The FAA is issuing this AD to address damage to the blowout vent grilles
in the forward and aft lower lobe cargo compartments that could lead to latent failure of
the decompression panels and pressure equalization valves. This latent failure, in
combination with a fire, could make the cargo fire protection, detection, suppression, and
containment system ineffective. Also, this latent failure, in combination with rapid
decompression of the airplane, could prevent activation of the station (STA) 1640
decompression panels, which could damage the STA 1640 floor beam and cause loss of
hydraulic systems components and flight control and damage to the auxiliary power unit
(APU) fuel line. This unsafe condition, if not addressed, could result in the inability of
the flightcrew to maintain safe flight and landing.
(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 757-25A0319 RB,
dated March 24, 2023, do all applicable actions identified in, and in accordance with, the
Accomplishment Instructions of Boeing Alert Requirements Bulletin 757-25A0319 RB,
dated March 24, 2023.
Note 1 to paragraph (g): Guidance for accomplishing the actions required by this
AD can be found in Boeing Alert Service Bulletin 757-25A0319, dated March 24, 2023,

which is referred to in Boeing Alert Requirements Bulletin 757-25A0319 RB, dated
March 24, 2023.
(h) Exceptions to Service Information Specifications
(1) For all airplanes: Where the Compliance Time columns of the tables in the
“Compliance” paragraph of Boeing Alert Requirements Bulletin 757-25A0319 RB, dated
March 24, 2023, refer to the original issue date of Requirements Bulletin
757-25A0319 RB, this AD requires using the effective date of this AD.
(2) For Groups 1, 2, and 4 airplanes identified in Boeing Alert Requirements
Bulletin 757-25A0319 RB, dated March 24, 2023, that have been converted from a
passenger to freighter configuration in accordance with VT Mobile Aerospace
Engineering (MAE) Inc. Supplemental Type Certificate (STC) ST04242AT or STC
ST03562AT or Precision Conversions LLC STC ST01529SE: Where the Compliance
Time columns of tables 1, 2, 3, and 5 in the “Compliance” paragraph of Boeing Alert
Requirements Bulletin 757-25A0319 RB, dated March 24, 2023, specify “Within 5,425
Flight Hours” and “Within 16 months,” this AD requires replacing that text with “Within
9,000 Flight Hours” and “Within 36 months,” respectively.
(3) For Group 6 airplanes identified in Boeing Alert Requirements Bulletin
757-25A0319 RB, dated March 24, 2023: Where the Compliance Time column of table 7
in the “Compliance” paragraph of Boeing Alert Requirements Bulletin 757-25A0319 RB,
dated March 24, 2023, specifies “Within 5,425 Flight Hours” and “Within 16 months,”
this AD requires replacing that text with “Within 9,000 Flight Hours” and “Within
36 months,” respectively.
(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:
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.
(j) Related Information
(1) For more information about this AD, contact Katherine Venegas, Aviation
Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone:
562-627-5353; email: Katherine.Venegas@faa.gov.
(2) Service information 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
(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) Boeing Alert Requirements Bulletin 757-25A0319 RB, dated March 24, 2023.
(ii) [Reserved]
(3) For service information, 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 service information 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
fr.inspection@nara.gov.
Issued on May 23, 2024.

Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2024-13014 Filed: 6/13/2024 8:45 am; Publication Date: 6/14/2024]