Airworthiness Directives; The Boeing Company Airplanes, 50513-50518 [2024-13014]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 89, Number 116 (Friday, June 14, 2024)]
[Rules and Regulations]
[Pages 50513-50518]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-13014]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-2003; Project Identifier AD-2022-01620-T; 
Amendment 39-22750; AD 2024-10-05]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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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 July 19, 2024.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of July 19, 
2024.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-2003; 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: 
562-627-5353; email: [email protected].

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

[[Page 50514]]

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

[[Page 50515]]

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 passenger-carrying 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

[[Page 50516]]

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 in-service 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.

[[Page 50517]]

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
----------------------------------------------------------------------------------------------------------------
                                                                                                  Cost on U.S.
            Action                  Labor cost            Parts cost          Cost per product      operators
----------------------------------------------------------------------------------------------------------------
Detailed Inspection...........  Up to 9 work-      $0......................  Up to $765 per     Up to $374,085
                                 hours x $85 per                              inspection cycle.  per inspection
                                 hour = $765 per                                                 cycle.
                                 inspection cycle.
Installation of decompression   Up to 12 work-     Up to 22,460............  Up to 23,480.....  Up to
 panels (465 airplanes).         hours x $85 per                                                 10,918,200.
                                 hour = $1,020.
Replacement of soft bulkhead    10 work-hours x    108,240.................  109,090..........  $10,909,000.
 (100 airplanes).                $85 per hour =
                                 $850.
Installation of doublers (7     2 work-hours x     1,760...................  1,930............  13,510.
 airplanes).                     $85 per hour =
                                 $170.
----------------------------------------------------------------------------------------------------------------

    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
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
Repair.....................................  12 work-hours x $85 per hour =              $54,120         $55,140
                                              $1,020.
Replacement................................  12 work-hour x $85 per hour =               108,240         109,260
                                              $1,020.
----------------------------------------------------------------------------------------------------------------

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

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:

2024-10-05 The Boeing Company: Amendment 39-22750; Docket No.

[[Page 50518]]

FAA-2023-2003; Project Identifier AD-2022-01620-T.

(a) Effective Date

    This airworthiness directive (AD) is effective July 19, 2024.

(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: [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 Katherine 
Venegas, Aviation Safety Engineer, FAA, 2200 South 216th St., Des 
Moines, WA 98198; telephone: 562-627-5353; email: 
[email protected].
    (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 [email protected].

    Issued on May 23, 2024.
Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-13014 Filed 6-13-24; 8:45 am]
BILLING CODE 4910-13-P