Document ID: FAA-2021-0828-0010
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2022-04-25T04:00Z

[Federal Register Volume 87, Number 79 (Monday, April 25, 2022)]
[Rules and Regulations]
[Pages 24267-24270]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-08694]

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 Rules and Regulations
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  Federal Register / Vol. 87, No. 79 / Monday, April 25, 2022 / Rules 
and Regulations  

[[Page 24267]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0828; Project Identifier AD-2021-00303-T; 
Amendment 39-21973; AD 2022-06-07]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2016-09-
01, which applied to certain The Boeing Company Model 777-200 and -300 
series airplanes. AD 2016-09-01 required repetitive inspections for 
cracking of the left- and right-side forward outer chords of the pivot 
bulkhead, and related investigative and corrective actions if 
necessary. AD 2016-09-01 also provided a modification of the pivot 
bulkhead, which terminated the repetitive inspections. This AD was 
prompted by reports of fatigue cracking of the forward outer chord of 
the station (STA) 2370 pivot bulkhead, and the determination that the 
compliance times need to be reduced, post-modification inspections must 
be done, and the inspections areas need to be expanded due to 
additional cracking found prior to the inspection times required by AD 
2016-09-01. This AD retains certain requirements of AD 2016-09-01. This 
AD also requires doing repetitive detailed and high frequency eddy 
current (HFEC) inspections of the longeron fitting, and, for post-
repair and post-modification inspections, the bulkhead assembly 
structure, for any cracking, and doing all applicable on-condition 
actions. The FAA is issuing this AD to address the unsafe condition on 
these products.

DATES: This AD is effective May 31, 2022.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of May 31, 
2022.

ADDRESSES: 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 https://www.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 
https://www.regulations.gov by searching for and locating Docket No. 
FAA-2021-0828.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0828; 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.

FOR FURTHER INFORMATION CONTACT: Luis Cortez-Muniz, Aerospace Engineer, 
Airframe Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: (206) 231-3958; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2016-09-01, Amendment 39-18499 (81 FR 
26109, May 2, 2016) (AD 2016-09-01). AD 2016-09-01 applied to certain 
The Boeing Company Model 777-200 and -300 series airplanes. The NPRM 
published in the Federal Register on October 14, 2021 (86 FR 57078). 
The NPRM was prompted by reports of fatigue cracking of the forward 
outer chord of the STA 2370 pivot bulkhead, and the determination that 
the compliance times need to be reduced, post-modification inspections 
must be done, and the inspections areas need to be expanded due to 
additional cracking found prior to the inspection times required by AD 
2016-09-01. In the NPRM, the FAA proposed to retain certain 
requirements of AD 2016-09-01. The NPRM also proposed to require doing 
repetitive detailed and HFEC inspections of the longeron fitting and, 
for certain airplanes, the bulkhead assembly structure, for any 
cracking and doing all applicable on-condition actions. The FAA is 
issuing this AD to address fatigue cracking of the outer flanges of the 
left and right side forward outer chords of the STA 2370 pivot 
bulkhead, which could result in a severed forward outer chord and 
consequent loss of horizontal stabilizer control.

Discussion of Final Airworthiness Directive

Comments

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

Request To Revise the Compliance Time

    Air France requested that Boeing and the FAA increase the 
inspection threshold to 1,000 flight cycles in the proposed AD. Air 
France stated that the proposed AD specifies that operators accomplish 
the nondestructive testing inspection within 500 flight cycles and that 
this threshold is not compatible in case of findings; this drives an 
operator to ground the airplane for a long period of time if a 
corrective action needs to be accomplished before further flight. Air 
France commented that a minimum of 300 man-hours are required to 
accomplish the corrective actions specified in Boeing Service Bulletin 
777-53-0076 [which is referenced in Boeing Alert Service Bulletin 777-
53A0075, Revision 2, dated February 22, 2021].

[[Page 24268]]

    Air France stated that its request allows operators to plan a C-
check maintenance visit during a time when a repair or the terminating 
action specified in Boeing Service Bulletin 777-53-0076 can be 
performed without disturbing airplane operations.
    The FAA disagrees with the commenter's request. As specified in 
Boeing Alert Service Bulletin 777-53A0075, Revision 2, dated February 
22, 2021, the compliance time of 500 flight cycles is a grace period 
and is only applicable when the airplane exceeds the inspection 
threshold. In addition, in developing an appropriate compliance time, 
the FAA coordinated with the manufacturer to provide a compliance time 
that maintains an acceptable level of safety. However, 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 the change would provide an 
acceptable level of safety. The FAA has not changed this final rule in 
this regard.

Request To Increase Frequency of Testing and Nondestructive Examining 
(NDE) Techniques

    An individual requested that Boeing increase the frequency of its 
testing in addition to exploring additional NDE techniques (e.g., 
ultrasonic testing) for identifying early indication of high cycle 
fatigue. The commenter stated that when looking at probability of 
failure, Boeing has identified at least 32 instances of cracking under 
the current inspection frequency; however, one of the biggest issues 
with the high cyclic fatigue cracking is that it is self-identifying. 
The individual commented that while there are various NDE tools and 
techniques that can be used to identify cracks once they have started 
to propagate, it is incredibly difficult to identify degraded 
conditions prior to fracture propagation. The commenter concluded that 
the probability of a crack developing unnoticed under the current 
inspection frequency should be considered moderate to high.
    While the FAA acknowledges the commenter's concern, this AD already 
incorporates reduced compliance times for the repetitive detailed and 
HFEC inspections, adds new inspection areas for any cracking and also 
adds repetitive post-modification inspections to the previous 
requirements of AD 2016-09-01. The determination of the mitigating 
actions and compliance times were coordinated with the manufacturer and 
determined to provide an appropriate interval of time while maintaining 
an acceptable level of safety. The FAA has not changed this AD in this 
regard.

Request To Clarify Certain Inspection Requirements

    Boeing requested that the SUMMARY section of the NPRM be revised to 
change the words, ``for certain airplanes, the bulkhead assembly 
structure'' to ``for post-repair and post-modification inspections, the 
bulkhead assembly structure.'' Boeing stated that the requested change 
is to clarify that the inspection of the bulkhead assembly structure is 
only required for airplanes that have accomplished the small crack 
repair option using Boeing Alert Service Bulletin 777-53A0075, Revision 
1, dated December 14, 2015, or the modification using Boeing Service 
Bulletin 777-53-0076.
    The FAA agrees that the proposed wording provides clarity and has 
revised the SUMMARY section of this AD accordingly.

Request To Correct Typographical Error

    Boeing requested that the FAA remove the words ``of the'' in the 
first sentence under the ``Proposed AD Requirements in this NPRM'' 
paragraph in the NPRM. Boeing stated that the sentence should be 
revised from ``retain certain of the requirements of AD 2016-09-01,'' 
to ``retain certain requirements of AD 2016-09-01.''
    The FAA acknowledges that ``of the'' in the first sentence under 
the ``Proposed AD Requirements in this NPRM'' paragraph in the NPRM 
should be removed; however, that paragraph is not carried over into 
this final rule.

Request To Revise Exception Language

    Boeing requested that the FAA revise paragraph (h)(1) of the 
proposed AD, which specifies using the effective date of this AD rather 
than the Revision 2 date of the service information, to remove the 
reference to the ``Effectivity'' paragraph and the Condition columns in 
the ``Compliance'' paragraph. Boeing stated that the phrase ``the 
Revision 2 date of this Service Bulletin'' is not used in those 
locations of the service information.
    The FAA agrees with the commenter's request and has revised 
paragraph (h)(1) of this AD accordingly.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. 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 Service Bulletin 777-53A0075, 
Revision 2, dated February 22, 2021. This service information specifies 
procedures for, depending on configuration, doing repetitive detailed 
and HFEC inspections of the STA 2370 pivot bulkhead forward outer chord 
and the longeron fitting for any cracking; doing repetitive post-repair 
inspections of the pivot bulkhead forward outer chord, longeron 
fitting, and bulkhead assembly structure for any cracking; doing 
repetitive post-modification inspections of the pivot bulkhead forward 
outer chord, longeron fitting, and bulkhead assembly structure for any 
cracking; and doing all applicable on-condition actions. On-condition 
actions include modifying the left and right forward outer chords and 
upper splice angles, 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 63 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 and HFEC inspections of   Up to 15 work-hours            $0  Up to $1,275 per      Up to $80,325 per
 the longeron fitting and pivot     x $85 per hour = Up                inspection cycle.     inspection cycle.
 bulkhead forward chord.            to $1,275 per
                                    inspection cycle.

[[Page 24269]]

 
Post-repair inspections..........  Up to 13 work-hours            $0  Up to $1,105 per      Up to $69,615 per
                                    x $85 per hour = Up                inspection cycle.     inspection cycle.
                                    to $1,105 per
                                    inspection cycle.
Post-modification inspections....  18 work-hours x $85            $0  $1,530 per            $96,390 per
                                    per hour = $1,530                  inspection cycle.     inspection cycle.
                                    per inspection
                                    cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
modifications that would be required based on the results of the 
inspection. The FAA has no way of determining the number of aircraft 
that might need this modification:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
              Action                         Labor cost           Parts cost           Cost per product
----------------------------------------------------------------------------------------------------------------
Modification......................  Up to 137 work-hours x $85       $34,086  Up to $45,731.
                                     per hour = Up to $11,645.
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the cost 
estimates for the repairs specified in this AD.
    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, 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.

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by:
0
a. Removing Airworthiness Directive (AD) 2016-09-01, Amendment 39-18499 
(81 FR 26109, May 2, 2016); and
0
b. Adding the following new AD:

2022-06-07 The Boeing Company: Amendment 39-21973; Docket No. FAA-
2021-0828; Project Identifier AD-2021-00303-T.

(a) Effective Date

    This airworthiness directive (AD) is effective May 31, 2022.

(b) Affected ADs

    This AD replaces AD 2016-09-01, Amendment 39-18499 (81 FR 26109, 
May 2, 2016) (AD 2016-09-01).

(c) Applicability

    This AD applies to The Boeing Company Model 777-200 and -300 
series airplanes, certificated in any category, as identified in 
Boeing Alert Service Bulletin 777-53A0075, Revision 2, dated 
February 22, 2021.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of fatigue cracking of the 
forward outer chord of the station (STA) 2370 pivot bulkhead, and 
the determination that the compliance times need to be reduced, 
post-modification inspections must be done, and the inspections 
areas need to be expanded due to additional cracking found prior to 
the inspection times required by AD 2016-09-01. The FAA is issuing 
this AD to address fatigue cracking of the outer flanges of the left 
and right side forward outer chords of the STA 2370 pivot bulkhead, 
which could result in a severed forward outer chord and consequent 
loss of horizontal stabilizer control.

(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 paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin 777-53A0075, Revision 2, dated 
February 22, 2021, do all applicable actions identified as ``RC'' 
(required for compliance) in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Service Bulletin 777-
53A0075, Revision 2, dated February 22, 2021.

[[Page 24270]]

(h) Exceptions to Service Information Specifications

    (1) Where the Compliance Time columns of the tables in the 
``Compliance'' paragraph of Boeing Alert Service Bulletin 777-
53A0075, Revision 2, dated February 22, 2021, use the phrase ``the 
Revision 2 date of this Service Bulletin,'' this AD requires using 
``the effective date of this AD.''
    (2) Where Boeing Alert Service Bulletin 777-53A0075, Revision 2, 
dated February 22, 2021, 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 Related Information. 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.
    (4) Except as specified by paragraph (h) of this AD: For service 
information that contains steps that are labeled as Required for 
Compliance (RC), the provisions of paragraphs (i)(4)(i) and (ii) of 
this AD apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. If a step or substep is labeled ``RC Exempt,'' then the 
RC requirement is removed from that step or substep. An AMOC is 
required for any deviations to RC steps, including substeps and 
identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(j) Related Information

    For more information about this AD, contact Luis Cortez-Muniz, 
Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch, 2200 
South 216th St., Des Moines, WA 98198; phone and fax: (206) 231-
3958; 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 Service Bulletin 777-53A0075, Revision 2, dated 
February 22, 2021.
    (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; internet https://www.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 [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on March 10, 2022.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2022-08694 Filed 4-22-22; 8:45 am]
BILLING CODE 4910-13-P