[Federal Register Volume 88, Number 102 (Friday, May 26, 2023)]
[Rules and Regulations]
[Pages 34081-34084]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-11305]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-1312; Project Identifier AD-2022-00551-T; 
Amendment 39-22420; AD 2023-08-05]
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 777 airplanes. This AD was prompted by 
reports of cracks found in the pivot bulkhead forward outer chord of a 
certain station. Analysis revealed higher bending stresses across the 
chord than originally assessed. This AD requires repetitive detailed 
and high frequency eddy current (HFEC) inspections of the pivot 
bulkhead forward outer chord of a certain station and longeron fitting 
for cracking and applicable on-condition actions. The FAA is issuing 
this AD to address the unsafe condition on these products.

DATES: This AD is effective June 30, 2023.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of June 30, 
2023.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2022-1312; 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; 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-2022-1312.

FOR FURTHER INFORMATION CONTACT: Luis Cortez-Muniz, Aerospace Engineer, 
Airframe Sections, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone: 206-231-3958; 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 777 airplanes. The NPRM published in the Federal Register 
on December 8, 2022 (87 FR 75179). The NPRM was prompted by reports of 
cracks found in the station (STA) 2370 pivot bulkhead forward outer 
chord. Analysis revealed higher bending stresses across the chord than 
originally assessed. In the NPRM, the FAA proposed to require 
repetitive detailed and HFEC inspections of the STA 2370 pivot bulkhead 
forward outer chord and longeron fitting for cracking and applicable 
on-condition actions. The FAA is issuing this AD to address cracking in 
the STA 2370 pivot bulkhead forward outer chord. Such cracking, if not 
detected and corrected, could result in a severed pivot bulkhead outer 
chord, loss of horizontal stabilizer control, and loss of 
controllability of the airplane.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from Boeing and the Air Line Pilots 
Association, International (ALPA), who supported the NPRM without 
change.
    The FAA received additional comments from three commenters, 
including Air France (AFA), Federal Express (FedEx) and United Airlines 
(UAL). The following presents the comments received on the NPRM and the 
FAA's response to each comment.

Request To Change Estimated and On-Condition Cost Sections

    FedEx requested a change to the Estimated and On-Condition Costs 
tables in the proposed AD. FedEx noted that, based on the estimates in 
Boeing Alert Service Bulletin 777-53A0098, dated April 5, 2022, the 
detailed and HFEC inspections require parts totaling $3,540, as well as 
62 work-hours for replacement for the on-condition requirements. FedEx 
added that the proposed AD states $0 parts cost for detailed and HFEC 
inspections and 7 work-hours for replacement if on-condition 
requirements are met.
    The FAA agrees with revising the parts cost and labor hours because 
the cost estimates provided in the proposed AD inadvertently excluded 
the parts costs for the inspections and the on-condition costs 
inadvertently omitted access and close-up costs. However, the FAA notes 
that the labor hours listed in Boeing Alert Service Bulletin 777-
53A0098, dated April 5, 2022, estimate 28 hours for the detailed and 
open hole HFEC inspection and 38 hours for the replacement (each 
estimate is for one side of the airplane). The FAA has revised the 
Costs of Compliance section of this AD accordingly.

Request To Change Work-Hour Estimates

    AFA suggested that Boeing Alert Service Bulletin 777-53A0098, dated 
April 5, 2022, greatly underestimates the total manpower hours required 
to perform the modification, which could lead to a maintenance program 
disruption if not taken into account by operators. AFA noted in its 
experience performing similar pivot bulkhead inspections and 
modification using similar service information, it took 1,200 work-
hours to complete the modification on both sides of the airplane. AFA 
added that, due to the time indicated to complete these service 
bulletins, resources were not available and the airplane was grounded 
for 3 weeks. AFA noted that it contacted two other operators, who 
confirmed they also spent between 900 and 1,100 hours to complete the 
modification on both sides of the airplane. AFA requested that the 
proposed AD highlight this work-hour discrepancy so operators can plan 
accordingly.
    The FAA acknowledges there may be discrepancies between the 
operator labor hours and the hours listed in Boeing Alert Service 
Bulletin 777-53A0098, dated April 5, 2022. Based on the best data 
available, the manufacturer provided the number of work hours necessary 
to do the required actions.

[[Page 34082]]

This number represents the time necessary to perform only the actions 
actually required by this AD. The FAA recognizes that, in doing the 
actions required by an AD, operators might incur incidental costs in 
addition to the direct costs. The cost analysis in AD rulemaking 
actions, however, typically does not include incidental costs such as 
the time necessary for planning or time necessitated by other 
administrative actions. Those incidental costs, which might vary 
significantly among operators, are almost impossible to calculate. In 
this case, the FAA has no way of knowing how much of the time estimates 
AFA provided are ``incidental'' costs. Further, as previously noted, 
the cost estimates in this AD have been revised to match those 
specified in the service information and are estimates for performing 
those actions on one side of the airplane. Therefore, the FAA has not 
revised this AD regarding this issue.

Request To Change Special Tooling Requirements

    AFA noted that Boeing Alert Service Bulletin 777-53A0098, dated 
April 5, 2022, paragraph 2.E advises no special tooling is needed, 
while paragraph 2.F advises that certain maintenance and overhaul tools 
are required. AFA explained that during similar modification they 
discovered that special big diameter reamers, drill bits and guides are 
required, which led to delays in work being performed because required 
reamers and drill bits were not available. AFA stated that Boeing 
advised that the tooling required is part of standard [maintenance, 
repair, and overhaul] MRO tools. However, AFA indicated these range of 
reamers and drill bit diameters are not common and not part of the 
standard available tools for an MRO. AFA requested that the proposed AD 
be revised to highlight the incomplete tooling information for 
operators to take into account before accomplishing the proposed 
requirements.
    The FAA acknowledges that additional tooling required may not be 
standard available tools for an MRO. However, the FAA has no definitive 
data regarding the standard MRO tools or what additional tools might be 
required. Further, the FAA notes that paragraphs 2.E. and 2.F. in 
Boeing Alert Service Bulletin 777-53A0098, dated April 5, 2022, are 
informational, and not required for compliance with this AD. The FAA 
has not changed this AD regarding this issue.

Request for Detailed Access Instructions

    AFA requested the proposed AD highlight that Chapter 3.B access and 
preparation instructions in Boeing Alert Service Bulletin 777-53A0098, 
dated April 5, 2022, are not detailed enough. AFA claimed a similar 
modification using different service information required removal of 
multiple systems and structural parts to get access to the damaged 
area. This required AFA to develop task cards on a daily basis and at 
mechanics' requests. AFA noted that it spent 300 work-hours after 
modification to restore access and perform tests. AFA stated that the 
additional work was not identified in the bulletin and caused delays 
completing the corresponding AD.
    The FAA acknowledges the commenters concerns, but notes that the 
access instructions are not required for compliance for this AD. 
Further, Boeing, as the design approval holder (DAH), is responsible 
for the development of these instructions. The FAA has no definitive 
guidance to provide access and preparation instructions. The FAA has 
not changed this AD regarding this issue.

Request To Allow Simultaneous Inspections of Both Sides of Aircraft

    UAL requested the proposed AD be revised to allow simultaneous 
inspections of both sides of the aircraft. UAL noted that paragraph 3.B 
of Boeing Alert Requirements Bulletin 777-53A0098 RB, dated April 5, 
2022, states ``Do all actions on one side before you do any action on 
the opposite side.'' UAL stated that it finds the restriction to be 
inconsistent with related service information requiring similar actions 
on other airplanes. UAL claimed that other service information stated 
that removal of structure (for repair or modification) simultaneously 
on both sides of the aircraft was unacceptable, but that removal of 
skin panels (for inspection) simultaneously on both sides of the 
aircraft was acceptable. UAL noted that the repair or replacement work 
is involved and lengthy, with the horizontal stabilizer immobilized and 
internally jacked, likely precluding other maintenance work in the 
area. UAL added that the repair process therefore disrupts the 
maintenance check, forcing the rescheduling of other planned 
maintenance action. UAL explained that inspecting both sides of the 
aircraft early and simultaneously would allow it to know the full scope 
of the project and plan accordingly. UAL noted that it asked Boeing to 
edit the service information to include this allowance, and Boeing 
agreed to incorporate the allowance in a proposed revision. For these 
reasons, UAL requested allowing the detailed and HFEC inspections 
simultaneously on both sides of the aircraft; or simultaneously with 
applicable on-condition actions on the opposite side of the aircraft; 
provided any on-condition repairs or replacements are not performed 
simultaneously on both sides of the aircraft.
    The FAA acknowledges the commenter's concern and the impact on 
maintenance planning. However, UAL has not provided substantiation in 
support of these exceptions. The FAA requires substantiation to support 
that no structural concerns are introduced with the requested 
exceptions and will consider their approval via alternative method of 
compliance (AMOC) request in accordance with paragraph (i) of this AD, 
provided an acceptable level of safety is maintained.

Request To Refer to Revised Service Information

    UAL requested that the FAA revise the proposed AD to refer to 
Revision 1 of Boeing Requirements Bulletin 777-53A0098 RB. UAL noted 
that it received a preliminary copy of the revised requirements 
bulletin for review, and that the revision corrects elements of the 
illustrations, step tables, and fastener code tables in the 
Accomplishment Instructions, including to figures which are Required 
for Compliance (RC). UAL stated that Revision 1 is expected to be 
published later this year, and mandating it would prevent operators 
from having to obtain AMOCs to use the corrected instructions.
    The FAA acknowledges the commenter's request. However, the FAA has 
not reviewed and approved Revision 1 of Boeing Requirements Bulletin 
777-53A0098 RB and notes that UAL did not request any specific changes 
to be able to comply with this AD. Further, the FAA may not refer to 
any document that does not yet exist in an AD. In general terms, the 
FAA is required by Office of the Federal Register (OFR) regulations for 
approval of materials incorporated by reference, as specified in 1 CFR 
51.1(f), to either publish the service document contents as part of the 
actual AD language; or submit the service document to the OFR for 
approval as referenced material, in which case the FAA may only refer 
to such material in the text of an AD. The AD may refer to the service 
document only if the OFR approved it for incorporation by reference. 
See 1 CFR part 51.

[[Page 34083]]

    Given the urgency of the identified unsafe condition, the FAA has 
determined that delaying this AD while the revised service information 
is developed, reviewed, and approved would be inappropriate. However, 
once the revised service information is approved, the FAA may consider 
granting an AMOC to allow the use of the revised service information.

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 777-53A0098 RB, 
dated April 5, 2022. This service information specifies procedures for 
repetitive detailed and HFEC inspections of the STA 2370 pivot bulkhead 
forward outer chord and longeron fitting for cracking and applicable 
on-condition actions. On-condition actions include replacing the pivot 
bulkhead forward outer chord and splice angle; a detailed inspection of 
the upper aft longeron extension fittings at STA 2370 to STA 2380 and 
open hole HFEC inspection of the STA 2370 pivot bulkhead web, aft outer 
chord, upper and lower outer chord, and skin for any crack; and repair.
    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 223 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
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Detailed and HFEC inspections...  10 work-hours x     $3,540 per          $4,390 per          $978,970
                                   $85 per hour =      inspection cycle.   inspection cycle.   inspection cycle.
                                   $850 per
                                   inspection cycle.
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    The FAA estimates the following costs to do any necessary 
replacements or inspections that would be required based on the results 
of the required inspection. The agency has no way of determining the 
number of aircraft that might need these replacements or inspections:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replacement (one side of airplane)............  38 work-hours x $85 per hour =           $37,720         $40,950
                                                 $3,230.
Detailed and open hole HFEC inspections (one    28 work-hours x $85 per hour =                 0           2,380
 side of airplane).                              $2,380.
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    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition repairs specified in this AD.
    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.
    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.

[[Page 34084]]

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2023-08-05 The Boeing Company: Amendment 39-22420; Docket No. FAA-
2022-1312; Project Identifier AD-2022-00551-T.

(a) Effective Date

    This airworthiness directive (AD) is effective June 30, 2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 777-200, -200LR, -
300, -300ER, and 777F airplanes, certificated in any category, as 
identified in Boeing Alert Requirements Bulletin 777-53A0098 RB, 
dated April 5, 2022.

(d) Subject

    Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by reports of cracks found in the station 
(STA) 2370 pivot bulkhead forward outer chord. Analysis revealed 
higher bending stresses across the chord than originally assessed. 
The FAA is issuing this AD to address cracking in the STA 2370 pivot 
bulkhead forward outer chord. Such cracking, if not detected and 
corrected, could result in a severed pivot bulkhead outer chord, 
loss of horizontal stabilizer control, and loss of controllability 
of the airplane.

(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 777-53A0098 RB, dated April 5, 2022, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
777-53A0098 RB, dated April 5, 2022.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
777-53A0098, dated April 5, 2022, which is referred to in Boeing 
Alert Requirements Bulletin 777-53A0098 RB, dated April 5, 2022.

(h) Exceptions to Service Information Specifications

    (1) Where the Compliance Time columns of the tables in the 
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 777-
53A0098 RB, dated April 5, 2022, use the phrase ``the original issue 
date of Requirements Bulletin 777-53A0098 RB,'' this AD requires 
using ``the effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 777-53A0098 RB, 
dated April 5, 2022, specifies contacting Boeing for repair 
instructions: This AD requires doing the repair using a method 
approved in accordance with the procedures specified in paragraph 
(i) of this AD.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, 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)(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, 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

    (1) For more information about this AD, contact Luis Cortez-
Muniz, Aerospace Engineer, Airframe Sections, FAA, Seattle ACO 
Branch, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-
3958; email: [email protected].
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (k)(3) and (4) 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 777-53A0098 RB, dated 
April 5, 2022.
    (ii) [Reserved]
    (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; 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 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 April 18, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-11305 Filed 5-25-23; 8:45 am]
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