[Federal Register Volume 83, Number 200 (Tuesday, October 16, 2018)]
[Proposed Rules]
[Pages 52173-52176]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-22278]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0900; Product Identifier 2018-NM-101-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and 
-500 series airplanes. This proposed AD was prompted by reports of 
cracking in the frame web, frame integral inboard chord, and fail-safe 
chord on multiple airplanes in multiple locations below the passenger 
floor, in addition to an evaluation by the design approval holder (DAH) 
indicating that certain fuselage frame splices are subject to 
widespread fatigue damage (WFD). This proposed AD would require 
repetitive inspections of certain fuselage upper frames, side frames, 
fail-safe chords, inboard chords, frame webs, and stringers; an 
inspection for the presence of repairs in certain inspections zones and 
open tooling holes; and applicable on-condition actions. We are 
proposing this AD to address the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by November 30, 
2018.

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.
     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-2018-0900.

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-2018-
0900; or in person at the Docket Management Facility 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 the Docket Office (phone: 
800-647-5527) is in the ADDRESSES section. Comments will be available 
in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Lu Lu, Aerospace Engineer, Airframe 
Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 
98198; phone and fax: 206-231-3525; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite 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-2018-0900; 
Product Identifier 2018-NM-101-AD'' at the beginning of your comments. 
We specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this NPRM. We will consider all 
comments received by the closing date and may amend this NPRM because 
of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

[[Page 52174]]

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 existing transport category airplanes and all of these 
airplanes that will be certificated in the future. For existing and 
future airplanes subject to the WFD rule, the rule requires that DAHs 
establish a limit of validity (LOV) of the engineering data that 
support the structural maintenance program. Operators affected by the 
WFD rule may not fly an airplane beyond its LOV, unless an extended LOV 
is approved.
    The WFD rule (75 FR 69746, November 15, 2010) 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 the LOV. Many LOVs, however, do 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.
    We have received a report indicating that cracking is being found 
in the frame web, frame integral inboard chord, and fail-safe chord on 
multiple frame locations, below the passenger floor, on multiple Model 
737-100, -200, -200C, -300, -400 and -500 series airplanes. In 
addition, the fuselage frame splices from station (STA) 380 to STA 520 
and STA 727A to STA 907 between stringers S-13 and S-14, are subject to 
WFD. This condition, if not addressed, could result in the cracks 
growing large enough to sever frames. Continued operation with multiple 
adjacent severed frames or a combination of a severed frame adjacent to 
fuselage skin cracks in chem-milled pockets could result in a loss of 
structural integrity or uncontrolled decompression.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-53A1360, dated June 
21, 2018. The service information describes procedures for repetitive 
inspections of certain fuselage upper frames, side frames, fail-safe 
chords, inboard chords, frame webs, and stringers; an inspection for 
the presence of repairs in certain inspections zones and open tooling 
holes; and applicable on-condition actions. 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

    We are proposing this AD because we 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 as ``RC'' (required for compliance) in the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1360, dated June 
21, 2018, described previously, except for any differences identified 
as exceptions in the regulatory text of this proposed AD and except as 
discussed under ``Differences Between this Proposed AD and the Service 
Information.''
    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-2018-0900.

Differences Between This Proposed AD and the Service Information

    Boeing Alert Service Bulletin 737-53A1360, dated June 21, 2018, 
specifies that the additional inspections and applicable on-condition 
actions identified in Table 9, ``Inspection of the Fuselage Frame 
Integral Inboard Chord and Web from STA 360 to STA 400, Right Side,'' 
of Boeing Alert Service Bulletin 737-53A1360, dated June 21, 2018, must 
be done only for Group 3 airplanes. However, this proposed AD also 
requires that for Group 2 and Groups 4 through 9 airplanes identified 
in Boeing Alert Service Bulletin 737-53A1360, dated June 21, 2018, that 
have been modified to a cargo configuration, those additional 
inspections and applicable on-condition actions must also be done. We 
have coordinated this difference with Boeing.

Costs of Compliance

    We estimate that this proposed AD affects 262 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
         Action               Labor cost              Parts cost          Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Inspections............  Up to 243 work-hours  None...................  Up to $20,655 per    Up to $5,411,610
                          x $85 per hour =                               inspection cycle.    per inspection
                          $20,655 per                                                         cycle.
                          inspection cycle.
----------------------------------------------------------------------------------------------------------------


[[Page 52175]]

    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition actions specified in this proposed 
AD.

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.
    We are 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 to the Director of the System Oversight 
Division.

Regulatory Findings

    We 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) Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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. FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

The Boeing Company: Docket No. FAA-2018-0900; Product Identifier 
2018-NM-101-AD.

(a) Comments Due Date

    We must receive comments by November 30, 2018.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes, certificated in any 
category, as identified in Boeing Alert Service Bulletin 737-
53A1360, dated June 21, 2018.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of cracking in the frame web, 
frame integral inboard chord, and fail-safe chord on multiple 
airplanes in multiple locations below the passenger floor, in 
addition to an evaluation by the design approval holder (DAH) 
indicating that the fuselage frame splices from station (STA) 380 to 
STA 520 and STA 727A to STA 907 between stringers S-13 and S-14 are 
subject to widespread fatigue damage (WFD). We are issuing this AD 
to address cracks in these locations, which could grow large enough 
to sever frames. Continued operation with multiple adjacent severed 
frames or a combination of a severed frame adjacent to fuselage skin 
cracks in chem-milled pockets could result in a loss of structural 
integrity or uncontrolled decompression.

(f) Compliance

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

(g) Actions for Group 1

    For airplanes identified as Group 1 in Boeing Alert Service 
Bulletin 737-53A1360, dated June 21, 2018: Within 120 days after the 
effective date of this AD, inspect the airplane and do all 
applicable on-condition actions using a method approved in 
accordance with the procedures specified in paragraph (k) of this 
AD.

(h) Inspection for Groups 2 Through 9

    For airplanes identified as Groups 2 through 9 in Boeing Alert 
Service Bulletin 737-53A1360, dated June 21, 2018, except as 
specified in paragraph (i) of this AD: At the applicable times 
specified in paragraph 1.E., ``Compliance,'' of Boeing Alert Service 
Bulletin 737-53A1360, dated June 21, 2018, do all applicable actions 
identified as ``RC'' (required for compliance) in, and in accordance 
with, the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1360, dated June 21, 2018.

(i) Exceptions to Service Information Specifications

    (1) For purposes of determining compliance with the requirements 
of this AD: Where Boeing Alert Service Bulletin 737-53A1360, dated 
June 21, 2018, uses the phrase ``the original issue date of this 
service bulletin,'' this AD requires using ``the effective date of 
this AD.''
    (2) Where Boeing Alert Service Bulletin 737-53A1360, dated June 
21, 2018, specifies contacting Boeing for repair instructions: This 
AD requires repair and applicable on-condition actions using a 
method approved in accordance with the procedures specified in 
paragraph (k) of this AD.
    (3) Where Boeing Alert Service Bulletin 737-53A1360, dated June 
21, 2018, specifies contacting Boeing for alternative inspections: 
This AD requires alternative inspections using a method approved in 
accordance with the procedures specified in paragraph (k) of this 
AD.
    (4) For airplanes identified as Group 2 and Groups 4 through 9 
in Boeing Alert Service Bulletin 737-53A1360, dated June 21, 2018, 
that have been modified to a cargo configuration: In addition to the 
actions required by paragraph (h) of this AD, the actions specified 
in Table 9, ``Inspection of the Fuselage Frame Integral Inboard 
Chord and Web from STA 360 to STA 400, Right Side,'' of Boeing Alert 
Service Bulletin 737-53A1360, dated June 21, 2018, must be done by 
doing all applicable actions identified as ``RC'' (required for 
compliance) in, and in accordance with, the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1360, dated 
June 21, 2018, at the applicable compliance times specified in Table 
9, ``Inspection of the Fuselage Frame Integral Inboard Chord and Web 
from STA 360 to STA 400, Right Side,'' of Boeing Alert Service 
Bulletin 737-53A1360, dated June 21, 2018, except as specified in 
paragraphs (i)(1) and (i)(2) of this AD.

(j) Terminating Actions for Repetitive Inspections

    (1) Accomplishment of a preventative modification specified in 
Part 7 of the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1360, dated June 21, 2018, at a tooling hole 
location, terminates the repetitive inspections specified in Part 6 
of the Accomplishment

[[Page 52176]]

Instructions of Boeing Alert Service Bulletin 737-53A1360, dated 
June 21, 2018, that are required by paragraph (h) of this AD, for 
that modified tooling hole location only.
    (2) Accomplishment of an high frequency eddy current inspection 
specified in Part 9 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-53A1360, dated June 21, 2018, terminates 
the repetitive inspections specified in Part 2 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1360, dated 
June 21, 2018, that are required by paragraph (h) of this AD, at the 
uppermost frame splice fastener location only.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles 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 (l)(2) 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 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 Commercial Airplanes Organization 
Designation Authorization (ODA) that has been authorized by the 
Manager, Los Angeles 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 required by paragraph (i) of this AD: For service 
information that contains steps that are labeled as RC, the 
provisions of paragraphs (k)(4)(i) and (k)(4)(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.

(l) Related Information

    (1) For more information about this AD, contact Lu Lu, Aerospace 
Engineer, Airframe Section, FAA, Seattle ACO Branch, 2200 South 
216th St., Des Moines, WA 98198; phone and fax: 206-231-3525; email: 
[email protected].
    (2) For information about AMOCs, contact George Garrido, 
Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5232; fax: 562-627-5210; email: [email protected].
    (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. 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 October 4, 2018.
Michael Kaszycki,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2018-22278 Filed 10-15-18; 8:45 am]
 BILLING CODE 4910-13-P