[Federal Register Volume 88, Number 58 (Monday, March 27, 2023)]
[Rules and Regulations]
[Pages 18011-18016]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-06075]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-1068; Project Identifier AD-2022-00358-T; 
Amendment 39-22364; AD 2023-04-17]
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 Boeing Model 737-8 and 737-9 airplanes, and certain Model 737-
600, -700, -700C, -800, -900, and -900ER series airplanes. This AD was 
prompted by reports of damage to the auxiliary power unit (APU) fuel 
line shroud located aft of the aft cargo area; investigation revealed 
that the placement of the pressure switch wire clamp assembly and its 
fastener allowed interference of the fastener against the APU fuel line 
shroud. This AD requires inspecting the APU fuel line shroud for 
damage, inspecting the pressure switch wire clamp for correct bolt 
orientation and horizontal distance from the APU fuel line shroud, and 
applicable on-condition actions. The FAA is issuing this AD to address 
the unsafe condition on these products.

DATES: This AD is effective May 1, 2023.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of May 1, 2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2022-1068; 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 identified in this final rule, 
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; internet 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-2022-1068.

FOR FURTHER INFORMATION CONTACT: Chris Baker, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone: 206-231-3552; 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 Boeing Model 
737-8 and 737-9 airplanes, and certain Model 737-600, -700, -700C, -
800, -900, and -900ER series airplanes. The NPRM

[[Page 18012]]

published in the Federal Register on October 5, 2022 (87 FR 60347). The 
NPRM was prompted by reports of damage to the auxiliary power unit 
(APU) fuel line shroud located aft of the aft cargo area; investigation 
revealed that the placement of the pressure switch wire clamp assembly 
and its fastener allowed interference of the fastener against the APU 
fuel line shroud. In the NPRM, the FAA proposed to require inspecting 
the APU fuel line shroud for damage, inspecting the pressure switch 
wire clamp for correct bolt orientation and horizontal distance from 
the APU fuel line shroud, and applicable on-condition actions. The FAA 
is issuing this AD to address interference of the fastener against the 
APU fuel line shroud, possibly resulting in a damaged APU fuel line 
shroud and consequent failure of the APU fuel hose, which could result 
in a flammable fluid leak in an ignition zone.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from The Air Line Pilots Association, 
International (ALPA), who supported the NPRM without change.
    The FAA received a comment from Aviation Partners Boeing (APB), who 
has reviewed the NPRM and determined that the incorporation of STC 
ST00830SE for installation of blended or split scimitar winglets on 
Boeing 737NG airplanes does not affect compliance with the mandated 
actions in the proposed rule. APB supported the NPRM without change.
    The FAA received additional comments from Erick Leon, Delta Air 
Lines (DAL), Southwest Airlines (SWA), Boeing, and American Airlines 
(AAL). The following presents the comments received on the NPRM and the 
FAA's response to each comment.

Request To Update Service Information

    Eric Leon requested that the procedure for installing the wire 
clamp should be updated to prevent the fuel line shroud from being 
damaged. The commenter noted that APU manufacturers should be required 
to make necessary corrections on the installation requirements for APU 
fuel line shroud. Lastly, the commenter stated that it would be 
important to understand what regulations are doing to ensure 
installation requirements meet minimum safety requirements set by the 
FAA.
    The FAA does not agree with the requested change by the commenter. 
As discussed in the NPRM, incorrect installation of the fastener of the 
pressure switch wire clamp allowed interference of the fastener against 
the APU fuel line shroud. This installation activity occurred as part 
of airplane production, and is not an area intended to be covered by 
the APU manufacturer's design or installation instructions. To address 
this issue, the Boeing Alert Requirements Bulletins mandated by this AD 
require an inspection to determine the orientation of the fastener 
installed for the pressure switch wire clamp. If the fastener is not 
installed correctly, it must be reinstalled according to the procedures 
provided by the Boeing Alert Requirements Bulletins. Correct 
installation of the fastener will eliminate the potential of the 
fastener contacting the APU fuel line shroud and prevent occurrences of 
damage to the APU fuel line shroud. Furthermore, the correct 
installation specified in the Boeing Alert Requirements Bulletins 
complies with applicable regulations and therefore meets the minimum 
FAA safety requirements. The FAA has not changed this AD in response to 
this comment.

Request To Include Revisions of Boeing Alert Requirements Bulletins

    DAL, AAL, and Boeing asked to revise the AD to require new 
revisions of service information that Boeing is currently drafting. 
Boeing noted that they are drafting revisions to Boeing Alert 
Requirements Bulletin 737-38A1072 RB, dated February 25, 2022, and 
Boeing Alert Requirements Bulletin 737-38A1073 RB, dated February 25, 
2022, to address the condition of a missing clamp. As an alternative, 
AAL asked the FAA to consider allowing ``later approved revisions'' of 
the service information.
    The FAA acknowledges the commenters' concerns regarding the 
procedures in the service information involving a potential missing 
clamp. In light of the critical nature of the identified unsafe 
condition, the FAA does not consider it appropriate to delay this final 
rule until new service information is available. Revisions of Boeing 
Alert Requirements Bulletins 737-38A1072 RB and 737-38A1073 RB have not 
been submitted to the FAA for review and approval. Therefore, the FAA 
is unable to mandate those revisions as requested. Furthermore, we 
disagree to add a provision to the AD to allow the use of ``later 
approved revisions'' of the Boeing Alert Requirements Bulletins. The 
FAA can only mandate a published document since the mandated document 
becomes part of the AD as it is incorporated by reference. Therefore, 
we are unable to mandate a ``later revision'' that does not exist at 
the time of AD publication. The FAA has not changed this AD in response 
to this comment.

Request To Provide Allowances for On-Wing Repairs of Damage to the APU 
Fuel Line Shroud

    DAL requested to provide allowances for on-wing repairs of damage 
to the APU fuel line shroud. DAL noted that any crack or hole found on 
the APU fuel line shroud or any damage which exposes bare metal on the 
APU fuel line shroud exceeding the blend-out limits requires replacing 
the existing shroud with a new or repaired shroud. DAL explained that 
the action of removing and re-installing the shroud represents a 
significant maintenance burden, estimated at up to 300 labor hours as 
noted in the Costs of Compliance/On-Condition Costs of the NPRM. DAL 
noted that they are aware of on-wing repair actions for similar damage 
on other aircraft models, which would alleviate the need for shroud 
removal, potentially reducing repair labor hours to approximately 20 
labor hours.
    The FAA does not agree with the requested change by DAL. The FAA is 
unable to provide allowances for on-wing repairs of the damaged APU 
fuel line shroud since such repair procedures are not provided in the 
service information mandated by this AD. However, if an alternative 
procedure is available that would provide an acceptable level of 
safety, such a procedure can be requested for FAA approval through the 
provisions of paragraph (i) of this AD. The FAA has not changed this AD 
in response to this comment.

Request Regarding Parts Availability

    DAL's review of parts availability from information on 
MyBoeingFleet Part Page shows zero stock of MPN 346A2201-26 APU Fuel 
Line Shroud as of October 5, 2022, with one part expected to be 
available by June 25, 2023. The subject MPN 346A2201-26 is applicable 
to approximately 100 DAL 737-900ER aircraft. DAL stated lack of 
availability of this part could severely hamper their ability to comply 
with this AD in the time period proposed.
    According to DAL, Boeing has advised DAL that they have what they 
believe to be an adequate number of MPN 346A2201-26 shrouds available, 
however these are under allocation control by Boeing. This condition 
minimizes an operator's ability to effectively plan for proper 
contingencies should a shroud require replacement as the operator will 
have to delay repair actions while awaiting Boeing to release

[[Page 18013]]

and ship the part to the operator potentially delaying aircraft return 
to service. DAL stated that if an AD will mandate this action, parts 
must be available to accomplish the requirements under paragraph (g) of 
the proposed AD.
    The FAA agrees to provide clarification. When the FAA assesses 
unsafe conditions and establishes compliance times for ADs, the agency 
accounts for the practical aspects associated with compliance, 
including parts availability. As indicated by the commenter, the 
manufacturer considers that parts availability will be adequate. 
Similarly, the FAA has not been informed of a potential shortage of 
necessary parts. Therefore, the FAA considers that the compliance time 
of three years is adequate for operators to acquire the necessary parts 
and accomplish the actions required by this AD. The FAA has not changed 
this AD in response to this comment.

Request To Include an Inspection for Clamp Presence as First Action and 
in Figure 2 of Boeing Alert Service Bulletin

    DAL requested to include an inspection for clamp presence as the 
first action rather than current ACTION 1, mandated per paragraph 
(g)(1) of the proposed AD under Boeing Alert Requirements Bulletin 737-
38A1072 RB, dated February 25, 2022. If the clamp is not installed, DAL 
requests a requirement to install the clamp prior to any work being 
performed. DAL also stated that Figure 2, sheet 3 of 4 of Boeing Alert 
Requirements Bulletin 737-38A1072 RB, dated February 25, 2022, should 
have a provision to inspect for the missing clamp prior to any work 
being performed. DAL suggested an additional paragraph be added to 
inspect for the missing clamp. DAL stated that if the final rule 
continues to require accomplishment of the Boeing Alert Requirements 
Bulletin rather than the forthcoming revision, ACTION 1 to establish 
inspection within 3 inches of the clamp cannot be accomplished if clamp 
is not present. Therefore, an inspection for the presence of the clamp 
must be done first. Then, installation of the clamp and the inspection 
included in ACTION 1 can be performed.
    The FAA does not agree with the requested changes by DAL. As stated 
previously, in light of the critical nature of the identified unsafe 
condition, the FAA does not consider it appropriate to delay this final 
rule until new service information is available. In addition, a 
pressure switch wire clamp should be present at the location specified 
in the service information mandated by the AD in order for an airplane 
to conform to the type design. We have not received any reports from 
the manufacturer regarding airplanes delivered with a missing pressure 
switch wire clamp. Also, we have not received any reports regarding the 
potential of the pressure switch wire clamp failing in service. 
Therefore, we consider that the instructions provided in the service 
information are adequate to address the unsafe condition. If an 
operator discovers an airplane with a missing pressure switch wire 
clamp during the accomplishment of the service information, we 
recommend that the operator inform the manufacturer of that condition. 
Operators may also request an Alternative Method of Compliance (AMOC) 
using the provisions in paragraph (i) of this AD if necessary. The FAA 
has not changed this AD in response to this comment.

Request To Clarify an Airplane Maintenance Manual (AMM) Reference

    DAL requested to clarify the AMM reference in Boeing Alert 
Requirements Bulletin 737-38A1072 RB, dated February 25, 2022, Part 2 
for APU Fuel line shroud removal/installation to indicate the MAIN APU 
fuel line shroud. DAL stated the AMM 28-25-05 has two shroud removal 
procedures--MAIN and AFT. In AMM 28-25-05/401, step 1.C notes that the 
APU shroud is divided into 2 parts with the main shroud being the one 
between the center tank and the pressure bulkhead, which is the subject 
of Boeing Alert Requirements Bulletin 737-38A1072 RB, dated February 
25, 2022, and the NPRM.
    The FAA agrees that the AMM reference should be clarified to 
reflect the intent of the AD, which is to replace the Main APU fuel 
line shroud only. However, the procedures in the Boeing Alert Service 
Bulletin (SB) that refer to AMM 28-25-05 are not required for 
compliance with this AD, and therefore those procedures are not 
provided in the Boeing Alert Requirements Bulletin (RB). As stated in 
Note 1 to paragraph (g)(1) and Note 2 to paragraph (g)(2) of this AD, 
the Boeing Alert Service Bulletins (SB) provide guidance for 
accomplishing the actions required by this AD. The FAA has not changed 
this AD in response to this comment.

Request for Additional Instructions in Boeing Alert Requirements 
Bulletin

    DAL stated that Boeing Alert Requirements Bulletin 737-38A1072 RB, 
dated February 25, 2022, Part 3, step 1.a. includes verbiage to ensure 
the damage is smoothed out and should not exceed 2 inches in length. 
DAL suggested an additional paragraph be provided to instruct operators 
to replace the existing shroud should the smoothing process require 
more than 2 inches. For Part 3, step 1.a., DAL stated there is no 
guidance should the smoothing be longer than 2 inches.
    Additionally, DAL stated that Boeing Alert Requirements Bulletin 
737-38A1072 RB, dated February 25, 2022, Part 3, step 1.b. indicates to 
not remove more than 0.018 inches of metal from the wall thickness. For 
Part 3, step 1.b., DAL stated there is no guidance should more than 
0.018 inches of metal be removed.
    The FAA does not agree with the requested changes by DAL. Although 
additional clarification as suggested by the commenter may be 
beneficial to operators, the FAA considers that the specific steps in 
the Requirements Bulletin (RB) are adequate to address the unsafe 
condition. Part 3 of the Service Bulletin (SB) provides one acceptable 
method of compliance. Part 3 of the SB provides an option to repair 
damage to the existing APU fuel line shroud. If the blend surface 
exceeds 2 inches, or if more than 0.018 inch of metal is removed from 
the wall thickness, the conditions required by Part 3 cannot be met, 
and therefore this option should not be taken. In this case, the FAA 
recommends the operator to follow the option provided by Part 2, which 
is to replace the APU fuel line shroud with a new or repaired shroud. 
As we clarified previously, the procedures identified by the commenter 
are not part of the Requirements Bulletin, and therefore are not 
required by this AD. Those procedures are provided in the Service 
Bulletin as guidance for accomplishing the actions required by this AD. 
The FAA has not changed this AD in response to this comment.

Request To Use Serviceable Parts

    SWA stated the ``Action'' column of Table 1 in Boeing Alert 
Requirements Bulletin 737-38A1072 RB, dated February 25, 2022, and 
Boeing Alert Requirements Bulletin 737-38A1073 RB, dated February 25, 
2022, specifies ``Replace existing APU fuel line shroud with new or 
repaired shroud.'' For Condition 1, Condition 2 (Option 2), and 
Condition 3, SWA requested clarification regarding the use of an APU 
fuel line shroud which is not ``new or repaired,'' but is otherwise in 
serviceable condition. We infer SWA requested that the FAA allow an 
option to use serviceable parts.
    The FAA agrees with the requested change by SWA. The service 
instructions should allow for

[[Page 18014]]

serviceable parts, not just ``new or repaired'' shrouds. This AD allows 
the installation of a ``serviceable'' APU fuel line shroud. A 
``serviceable'' APU fuel line shroud is defined as an APU fuel line 
shroud that has been maintained using methods acceptable to the FAA and 
identified by the FAA as airworthy. The FAA has added paragraphs (h)(3) 
and (4) to this AD to include this information.

Request To Clarify the Location of the APU Fuel Line Shroud Damage

    Boeing requested to clarify the location of the APU fuel line 
shroud damage. Boeing proposed to revise paragraph (e) of the NPRM to 
change the statement from: ``This AD was prompted by reports of damage 
to the auxiliary power unit (APU) fuel line shroud located in the aft 
cargo area'' to: ``This AD was prompted by reports of damage to the 
auxiliary power unit (APU) fuel line shroud located aft of the aft 
cargo area.'' This will more precisely describe the location of the APU 
fuel line shroud damage that was found.
    The FAA agrees with the requested change by Boeing because it 
better describes the location of the APU fuel line shroud. The FAA has 
changed the SUMMARY, Background, and paragraph (e) of this AD as 
requested.

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 Bulletins 737-38A1072 RB 
and 737-38A1073 RB, both dated February 25, 2022. This service 
information specifies procedures for a general visual inspection of the 
APU fuel line shroud in the area within 3 inches of the fastener of the 
pressure switch wire clamp for any damage (any crack or hole, any 
damage that exposes bare metal on the APU fuel line shroud, and any 
dent damage found that decreases the outside diameter of the shroud by 
more than 0.031 inch); a detailed inspection of the pressure switch 
wire clamp to determine if the fastener of the pressure switch wire 
clamp is installed with the bolt head on top and the nut on the bottom, 
and that there is a minimum 1.5 inches of horizontal separation between 
the fastener of the pressure switch wire clamp and the APU fuel line 
shroud, and applicable on-condition actions. On-condition actions 
include replacing the existing APU fuel line shroud with a new or 
repaired shroud; repairing any damage to the APU fuel line shroud; 
reinstalling the fastener of the pressure switch wire clamp with the 
bolt head on top and the nut on the bottom; and reinstalling the 
pressure switch wire clamp assembly to make sure there is 1.5 inches 
minimum of horizontal separation between the fastener of the pressure 
switch wire clamp and the APU fuel line shroud. These documents are 
distinct since they apply to different airplane minor models. 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 ADDRESSES.

Costs of Compliance

    The FAA estimates that this AD affects 1,919 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost per       Cost on U.S.
               Action                        Labor cost           Parts cost        product         operators
----------------------------------------------------------------------------------------------------------------
One-time Inspections................  2 work-hours x $85 per               $0             $170         $326,230
                                       hour = $170.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary repairs, 
replacements, or re-installations that would be required based on the 
results of the inspection. The agency has no way of determining the 
number of aircraft that might need these repairs, replacements, or re-
installations:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
              Action                    Labor cost               Parts cost               Cost per product
----------------------------------------------------------------------------------------------------------------
Repair...........................  Up to 3 work-hours x  $0.......................  Up to $255.
                                    $85 per hour = Up
                                    to $255.
Replacement (includes re-          Up to 300 work-hours  Up to $8,158.............  Up to $33,658.
 installation).                     x $85 per hour = Up
                                    to $25,500.
----------------------------------------------------------------------------------------------------------------

    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some or all of the costs of 
this AD may be covered under warranty, thereby reducing the cost impact 
on affected operators.

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.

[[Page 18015]]

    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:

2023-04-17 The Boeing Company: Amendment 39-22364; Docket No. FAA-
2022-1068; Project Identifier AD-2022-00358-T.

(a) Effective Date

    This airworthiness directive (AD) is effective May 1, 2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company airplanes identified in 
paragraphs (c)(1) and (2) of this AD, certificated in any category.
    (1) Model 737-600, -700, -700C, -800, -900, and -900ER series 
airplanes, as identified in Boeing Alert Requirements Bulletin 737-
38A1072 RB, dated February 25, 2022.
    (2) Model 737-8 and 737-9 airplanes, as identified in Boeing 
Alert Requirements Bulletin 737-38A1073 RB, dated February 25, 2022.

(d) Subject

    Air Transport Association (ATA) of America Code 28, Fuel.

(e) Unsafe Condition

    This AD was prompted by reports of damage to the auxiliary power 
unit (APU) fuel line shroud located aft of the aft cargo area; 
investigation revealed that the placement of the pressure switch 
wire clamp assembly and the fastener allowed interference of the 
fastener against the APU fuel line shroud. The FAA is issuing this 
AD to address interference of the fastener against the APU fuel line 
shroud, possibly resulting in a damaged APU fuel line shroud and 
consequent failure of the APU fuel hose, which could result in a 
flammable fluid leak in an ignition zone.

(f) Compliance

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

(g) Required Actions

    (1) For the airplanes identified in paragraph (c)(1) of this AD, 
except as specified by paragraph (h) of this AD: At the applicable 
times specified in the ``Compliance'' paragraph of Boeing Alert 
Requirements Bulletin 737-38A1072 RB, dated February 25, 2022, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-38A1072 RB, dated February 25, 2022.

    Note 1 to paragraph (g)(1): Guidance for accomplishing the 
actions required by this AD can be found in Boeing Alert Service 
Bulletin 737-38A1072, dated February 25, 2022, which is referred to 
in Boeing Alert Requirements Bulletin 737-38A1072 RB, dated February 
25, 2022.

    (2) For the airplanes identified in paragraph (c)(2) of this AD, 
except as specified by paragraph (h) of this AD: At the applicable 
times specified in the ``Compliance'' paragraph of Boeing Alert 
Requirements Bulletin 737-38A1073 RB, dated February 25, 2022, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-38A1073 RB, dated February 25, 2022.

    Note 2 to paragraph (g)(2): Guidance for accomplishing the 
actions required by this AD can be found in Boeing Alert Service 
Bulletin 737-38A1073, dated February 25, 2022, which is referred to 
in Boeing Alert Requirements Bulletin 737-38A1073 RB, dated February 
25, 2022.

(h) Exceptions to Service Information Specifications

    (1) Where the Compliance Time columns of the tables in the 
``Compliance'' paragraphs of Boeing Alert Requirements Bulletin 737-
38A1072 RB, dated February 25, 2022, use the phrase ``the original 
issue date of Requirements Bulletin 737-38A1072 RB,'' this AD 
requires using ``the effective date of this AD.''
    (2) Where the Compliance Time columns of the tables in the 
``Compliance'' paragraphs of Boeing Alert Requirements Bulletin 737-
38A1073 RB, dated February 25, 2022, use the phrase ``the original 
issue date of Requirements Bulletin 737-38A1073 RB,'' this AD 
requires using ``the effective date of this AD.''
    (3) Where the Action column in Table 1 of Boeing Alert 
Requirements Bulletin 737-38A1072 RB, dated February 25, 2022, uses 
the phrase ``Replace existing APU fuel line shroud with new or 
repaired shroud,'' this AD allows the installation of a 
``serviceable'' APU fuel line shroud. A ``serviceable'' APU fuel 
line shroud is defined as an APU fuel line shroud that has been 
maintained using methods acceptable to the FAA and identified by the 
FAA as airworthy.
    (4) Where the Action column in Table 1 of Boeing Alert 
Requirements Bulletin 737-38A1073 RB, dated February 25, 2022, uses 
the phrase ``Replace existing APU fuel line shroud with new or 
repaired shroud,'' this AD allows the installation of a 
``serviceable'' APU fuel line shroud. A ``serviceable'' APU fuel 
line shroud is defined as an APU fuel line shroud that has been 
maintained using methods acceptable to the FAA and identified by the 
FAA as airworthy.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle ACO 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: [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, Seattle 
ACO 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

    For more information about this AD, contact Chris Baker, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3552; 
email: [email protected].

(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 737-38A1072 RB, dated 
February 25, 2022.
    (ii) Boeing Alert Requirements Bulletin 737-38A1073 RB, dated 
February 25, 2022.
    (3) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; telephone 562-797-1717; internet myboeingfleet.com.
    (4) You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th

[[Page 18016]]

St., Des Moines, WA. For information on the availability of this 
material at the FAA, call 206-231-3195.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on February 22, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-06075 Filed 3-24-23; 8:45 am]
BILLING CODE 4910-13-P