[Federal Register Volume 85, Number 23 (Tuesday, February 4, 2020)]
[Proposed Rules]
[Pages 6107-6110]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-02016]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0089; Product Identifier 2019-NM-159-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

[[Page 6108]]

certain The Boeing Company Model 737-700, -800, and -900ER series 
airplanes. This proposed AD was prompted by a report of unshimmed gaps 
at a certain inner chord. This proposed AD would require a general 
visual inspection for repairs of a certain inner chord, a detailed 
inspection for unshimmed gaps of the frame inner chord, and applicable 
on-condition actions. The FAA is proposing this AD to address the 
unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by March 20, 
2020.

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 https://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 https://www.regulations.gov by 
searching for and locating Docket No. FAA-2020-0089.

Examining the AD Docket

    You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
0089; 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: Greg Rutar, Aerospace Engineer, 
Airframe Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3529; email: 
[email protected].

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-2020-0089; 
Product Identifier 2019-NM-159-AD'' at the beginning of your comments. 
The FAA 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 received, without change, to https://www.regulations.gov, including any personal information you provide. 
The FAA will also post a report summarizing each substantive verbal 
contact received about this proposed AD.

Discussion

    The FAA has received a report of unshimmed gaps found during 
production at the station (STA) 727 frame inner chord common to the 
stringer (S) 18A web on multiple airplanes, on both the left and right 
sides of the fuselage. Airplanes that were found to have gaps in 
production were corrected prior to delivery; however, a quality 
investigation determined that certain airplanes previously delivered 
might have gaps. These gaps could initiate early cracking in fatigue 
critical baseline structure (FCBS). Such cracking, if not addressed, 
may result in the inability of a principal structural element (PSE) to 
sustain limit load and adversely affect the structural integrity of the 
airplane.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 737-53A1385 RB, 
dated August 16, 2019. This service information describes procedures 
for a general visual inspection for repairs of the STA 727 frame inner 
chord at S-18A, a detailed inspection for unshimmed gaps of the frame 
inner chord at S-18A, and applicable on-condition actions including an 
initial high frequency eddy current inspection for cracking of the 
frame inner chord at S-18A, repair, shim installation between the frame 
inner chord and S-18A, and repetitive high frequency eddy current 
inspections for cracking of the frame inner chord at S-18A.
    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 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 in Boeing Alert Requirements Bulletin 737-53A1385 RB, dated 
August 16, 2019, described previously, except for any differences 
identified as exceptions in the regulatory text of this proposed AD.
    For information on the procedures and compliance times, see this 
service information at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2020-0089.

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 56 airplanes of 
U.S. registry. The FAA estimates the following costs to comply with 
this proposed AD:

[[Page 6109]]



                                      Estimated Costs for Required Actions
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                                                                                Cost per         Cost on U.S.
              Action                      Labor cost           Parts cost        product          operators
----------------------------------------------------------------------------------------------------------------
Inspection for repairs...........  3 work-hours x $85 per                $0            $255  $14,280.
                                    hour = $255.
Detailed inspection..............  1 work-hour x $85 per                  0              85  Up to $4,760.
                                    hour = $85.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary on-
condition actions that would be required. The FAA has no way of 
determining the number of aircraft that might need these on-condition 
actions:

                                     Estimated Costs of On-Condition Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
HFEC inspection............................  Up to 3 work-hours x $85 per hour =              $0            $255
                                              $255.
Shim installation..........................  2 work-hours x $85 per hour = $170.               0             170
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data that would enable the 
agency to provide cost estimates for the on-condition alternative 
inspections and certain repair and 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 FAA has included 
all known costs in the 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.

Regulatory Findings

    The FAA has 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-2020-0089; Product Identifier 
2019-NM-159-AD.

(a) Comments Due Date

    The FAA must receive comments by March 20, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-700, -800, and -
900ER series airplanes, certificated in any category, as identified 
in Boeing Alert Requirements Bulletin 737-53A1385 RB, dated August 
16, 2019.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a report of unshimmed gaps at the 
station (STA) 727 frame inner chord common to the stringer (S) 18A 
web. The FAA is issuing this AD to address such gaps, which may 
initiate early cracking in fatigue critical baseline structure 
(FCBS) and result in the inability of a principal structural element 
(PSE) to sustain limit load and adversely affect the structural 
integrity 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 737-53A1385 RB, dated August 16, 2019, 
do all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-53A1385 RB, dated August 16, 2019.

    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-53A1385, dated August 16, 2019, which is referred to in Boeing 
Alert Requirements Bulletin 737-53A1385 RB, dated August 16, 2019.

(h) Exceptions to Service Information Specifications

    (1) For purposes of determining compliance with the requirements 
of this AD: Where Boeing Alert Requirements Bulletin 737-53A1385 RB, 
dated August 16, 2019, uses the phrase ``the original issue date of 
the Requirements Bulletin 737-53A1385 RB'' or ``the original issue 
date of Requirements Bulletin 737-53A1385 RB,'' this AD requires

[[Page 6110]]

using ``the effective date of this AD,'' except where Boeing Alert 
Requirements Bulletin 737-53A1385 RB, dated August 16, 2019, uses 
the phrase ``the original issue date of Requirements Bulletin 737-
53A1385 RB'' in a note or flag note.
    (2) Where Boeing Alert Requirements Bulletin 737-53A1385 RB, 
dated August 16, 2019, specifies contacting Boeing for repair 
instructions, alternative inspections, and applicable on-condition 
actions: This AD requires accomplishing those actions 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 [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 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 Greg Rutar, 
Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch, 2200 
South 216th St., Des Moines, WA 98198; phone and fax: 206-231-3529; 
email: [email protected].
    (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 on January 28, 2020.
Gaetano A. Sciortino,
 Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2020-02016 Filed 2-3-20; 8:45 am]
 BILLING CODE 4910-13-P