[Federal Register Volume 84, Number 153 (Thursday, August 8, 2019)]
[Proposed Rules]
[Pages 38889-38892]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-16841]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0603; Product Identifier 2019-NM-087-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain The Boeing Company Model 777-300ER and 777F series 
airplanes. This proposed AD was prompted by an evaluation by the design 
approval holder (DAH) indicating that the fuselage stringers, stringer 
splices, and skin splice straps are subject to widespread fatigue 
damage (WFD). This proposed AD would require repetitive detailed 
inspections of certain stringer splices and skin splice straps for any 
cracks, repetitive high frequency eddy current (HFEC) inspections of 
certain stringers and stringer splices for any cracks, and applicable 
on-condition actions. The agency is proposing this AD to address the 
unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by September 
23, 2019.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.

[[Page 38890]]

     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, 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 referenced service information at the FAA, Transport 
Standards 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 on the internet at http://www.regulations.gov by 
searching for and locating Docket No. FAA-2019-0603.

Examining the AD Docket

    You may examine the AD docket on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2019-
0603; 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 NPRM, the regulatory evaluation, any comments received, and other 
information. The street address for Docket Operations is listed above. 
Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Eric Lin, Aerospace Engineer, Airframe 
Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 
98198; phone and fax: 206-231-3523; email: eric.lin@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2019-0603; 
Product Identifier 2019-NM-087-AD'' at the beginning of your comments. 
The agency specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of this NPRM. The FAA will 
consider all comments received by the closing date and may amend this 
NPRM because of those comments.
    The FAA will post all comments, without change, to http://www.regulations.gov, including any personal information you provide. 
The agency will also post a report summarizing each substantive verbal 
contact received about this proposed AD.

Discussion

    Fatigue damage can occur locally, in small areas or structural 
design details, or globally, in widespread areas. Multiple-site damage 
is widespread damage that occurs in a large structural element such as 
a single rivet line of a lap splice joining two large skin panels. 
Widespread damage can also occur in multiple elements such as adjacent 
frames or stringers. Multiple-site damage and multiple-element damage 
cracks are typically too small initially to be reliably detected with 
normal inspection methods. Without intervention, these cracks will 
grow, and eventually compromise the structural integrity of the 
airplane. This condition is known as WFD. It is associated with general 
degradation of large areas of structure with similar structural details 
and stress levels. As an airplane ages, WFD will likely occur, and will 
certainly occur if the airplane is operated long enough without any 
intervention.
    The FAA's WFD final rule (75 FR 69746, November 15, 2010) became 
effective on January 14, 2011. The WFD rule requires certain actions to 
prevent structural failure due to WFD throughout the operational life 
of certain transport category airplanes that had already been 
certificated by the FAA at the time of that rule's enactment, and all 
transport-category airplanes to be certificated afterward. The rule 
requires that DAHs establish a limit of validity (LOV) of the 
engineering data that support the airplanes' structural maintenance 
program. Operators affected by the WFD rule may not fly an airplane 
beyond its LOV, unless the FAA approves an extended LOV.
    The WFD rule does not require identifying and developing 
maintenance actions if the DAHs can show that such actions are not 
necessary to prevent WFD before the airplane reaches its LOV. Many 
LOVs, however, depend on accomplishment of future maintenance actions. 
As stated in the WFD rule, any maintenance actions necessary to reach 
the LOV will be mandated by airworthiness directives through separate 
rulemaking actions.
    In the context of WFD, this action is necessary to enable DAHs to 
propose LOVs that allow operators the longest operational lives for 
their airplanes, and still ensure that WFD will not occur. This 
approach allows for an implementation strategy that provides 
flexibility to DAHs in determining the timing of service information 
development (with FAA approval), while providing operators with 
certainty regarding the LOV applicable to their airplanes.
    The FAA has received a report indicating that aluminum chips and 
conical burr foreign object debris (FOD), were found on in-production 
model 777-300ER and 777F airplanes in the interfaces beneath stringer 
splices at station (STA) 825+210, STA 655, and STA 1434+189, and the 
circumferential splices at STA 1832. FOD has been found in splices that 
were built using an automated drilling and fastener installation 
process. This automated process is not always sufficient to close gaps 
that can occur as a result of the manufacturing build sequence and 
geometry. This process has also resulted in hole defects at these 
stations. A product acceptance plan has been inadequate in finding 
holes that were out of tolerance. FOD and hole defects can reduce the 
fatigue performance of the splices, and the existing Maintenance 
Planning Data (MPD) inspections do not provide adequate crack detection 
for the reduced fatigue thresholds. This could lead to undetected 
cracking.
    This condition, if not addressed, could result in undetected 
fatigue cracks, which could adversely affect the structural integrity 
of the airplane.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 777-53A0091 RB, 
dated April 8, 2019. The service information describes procedures for 
repetitive detailed inspections of certain stringer splices and skin 
splice straps for any cracks, repetitive HFEC inspections of certain 
stringers and stringer splices for any cracks, and applicable on-
condition actions. On-condition actions include 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 the ADDRESSES section.

FAA's Determination

    The FAA is proposing this AD because the agency evaluated all the 
relevant information and determined the unsafe condition described 
previously is likely to exist or develop in other products of the same 
type design.

Proposed AD Requirements

    This proposed AD would require accomplishment of the actions 
identified in Boeing Alert Requirements Bulletin 777-53A0091 RB, dated 
April 8, 2019, described previously, except for any differences 
identified as exceptions

[[Page 38891]]

in the regulatory text of this proposed AD.
    For information on the procedures and compliance times, see this 
service information at http://www.regulations.gov by searching for and 
locating Docket No. FAA-2019-0603.

Explanation of Requirements Bulletin

    The FAA worked in conjunction with industry, under the 
Airworthiness Directive Implementation Aviation Rulemaking Committee 
(AD ARC), to enhance the AD system. One enhancement is a process for 
annotating which steps in the service information are ``required for 
compliance'' (RC) with an AD. Boeing has implemented this RC concept 
into Boeing service bulletins.
    In an effort to further improve the quality of ADs and AD-related 
Boeing service information, a joint process improvement initiative was 
worked between the FAA and Boeing. The initiative resulted in the 
development of a new process in which the service information more 
clearly identifies the actions needed to address the unsafe condition 
in the ``Accomplishment Instructions.'' The new process results in a 
Boeing Requirements Bulletin, which contains only the actions needed to 
address the unsafe condition (i.e., only the RC actions).

Costs of Compliance

    The FAA estimates that this proposed AD affects 12 airplanes of 
U.S. registry. The agency estimates the following costs to comply with 
this proposed AD:

                                      Estimated Costs for Required Actions
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                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
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Detailed and HFEC Inspections....  Up to 79 work-hours              $0  Up to $6,715 per     Up to $80,580 per
                                    x $85 per hour =                     inspection cycle.    inspection cycle.
                                    Up to $6,715 per
                                    inspection cycle.
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    The FAA has have received no definitive data that would enable us 
to provide cost estimates for the on-condition actions specified in 
this proposed AD.
    According to the manufacturer, some or all of the costs of this 
proposed AD may be covered under warranty, thereby reducing the cost 
impact on affected individuals. The FAA does not control warranty 
coverage for affected individuals. As a result, the agency has included 
all known costs in its cost estimate.

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.
    This proposed AD is issued in accordance with authority delegated 
by the Executive Director, Aircraft Certification Service, as 
authorized by FAA Order 8000.51C. In accordance with that order, 
issuance of ADs is normally a function of the Compliance and 
Airworthiness Division, but during this transition period, the 
Executive Director has delegated the authority to issue ADs applicable 
to transport category airplanes and associated appliances to the 
Director of the System Oversight Division.

Regulatory Findings

    The FAA determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 this proposed 
regulation:
    (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 Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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 (AD):

The Boeing Company: Docket No. FAA-2019-0603; Product Identifier 
2019-NM-087-AD.

(a) Comments Due Date

    The FAA must receive comments by September 23, 2019.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 777-300ER and 777F 
series airplanes, certificated in any category, as identified in 
Boeing Alert Requirements Bulletin 777-53A0091 RB, dated April 8, 
2019.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by an evaluation by the design approval 
holder (DAH) indicating that the fuselage stringers, stringer 
splices, and skin splice straps are subject to widespread fatigue 
damage (WFD). The FAA is issuing this AD to address undetected 
fatigue cracks, which could adversely affect the structural 
integrity of the airplane.

(f) Compliance

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

[[Page 38892]]

(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 777-53A0091 RB, dated April 8, 2019, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
777-53A0091 RB, dated April 8, 2019.

    Note 1 to paragraph (g):  Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
777-53A0091, dated April 8, 2019, which is referred to in Boeing 
Alert Requirements Bulletin 777-53A0091 RB, dated April 8, 2019.

(h) Exceptions to Service Information Specifications

    (1) For purposes of determining compliance with the requirements 
of this AD: Where Boeing Alert Requirements Bulletin 777-53A0091 RB, 
dated April 8, 2019, uses the phrase ``the original issue date of 
Requirements Bulletin 777-53A0091 RB'' or ``the original issue date 
of this service bulletin,'' this AD requires using ``the effective 
date of this AD,'' except where Boeing Alert Requirements Bulletin 
777-53A0091 RB, dated April 8, 2019, uses the phrase ``the original 
issue date of this service bulletin'' in a note or flag note.
    (2) Where Boeing Alert Requirements Bulletin 777-53A0091 RB, 
dated April 8, 2019, specifies contacting Boeing for repair 
instructions: This AD requires doing the repair before further 
flight 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 local Flight Standards District 
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: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district 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 Eric Lin, 
Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch, 2200 
South 216th St., Des Moines, WA 98198; phone and fax: 206-231-3523; 
email: eric.lin@faa.gov.
    (2) 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. You may view this referenced service 
information at the FAA, Transport Standards Branch, 2200 South 216th 
St., Des Moines, WA. For information on the availability of this 
material at the FAA, call 206-231-3195.

    Issued in Des Moines, Washington, on July 26, 2019.
Dionne Palermo,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2019-16841 Filed 8-7-19; 8:45 am]
 BILLING CODE 4910-13-P


