[Federal Register Volume 85, Number 107 (Wednesday, June 3, 2020)]
[Proposed Rules]
[Pages 34136-34139]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-11828]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0459; Product Identifier 2020-NM-049-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 all The Boeing Company Model 737 series airplanes, excluding Model 
737-100, -200, -200C, -300, -400, and -500 series airplanes. This 
proposed AD was prompted by reports of cracked or completely severed 
lugs in the upper aft corner stop fitting assembly of the forward entry 
door. This proposed AD would require an inspection, a measurement, or a 
records check of that assembly to determine the part number, and 
replacement if a certain part is found. 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 July 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.

[[Page 34137]]

    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, 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 on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
0459.

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-
0459; 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, 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: Michael Bumbaugh, Aerospace Engineer, 
Airframe Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3522; email: 
michael.bumbaugh@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-2020-0459; 
Product Identifier 2020-NM-049-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.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, 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.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this NPRM. Submissions containing CBI should be sent to FAA 
Aerospace Engineer Michael Bumbaugh at the previously-listed contact 
information. Any commentary that the FAA receives which is not 
specifically designated as CBI will be placed in the public docket for 
this rulemaking.

Discussion

    The FAA has received reports of cracked and completely severed lugs 
in the stop fitting assembly of the forward entry door on Boeing Model 
737 Next Generation (NG) airplanes. Analysis of the design of the stop 
fitting assembly revealed that undersized wall thickness of the lug 
made it susceptible to fatigue cracking. The FAA has determined that 
the failure of the door stop fitting assembly may result in the forward 
entry door being unable to sustain limit load. This condition, if not 
addressed, could result in reduced structural integrity of the forward 
entry door and consequent rapid decompression of the airplane.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 737-52A1180 RB, 
dated January 24, 2020. The service information describes procedures 
for an inspection, a measurement, or a records check of the upper aft 
corner door stop fitting assembly to determine the part number, and 
applicable on-condition actions. The on-condition action is to replace 
the affected stop fitting assembly with a newly designed stop fitting 
assembly that has improved wall thickness and strength. 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 737-52A1180 RB, dated 
January 24, 2020, described previously, except as discussed under 
``Differences Between this Proposed AD and the Service Information,'' 
and 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-2020-0459.

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).

Differences Between This Proposed AD and the Service Information

    The effectivity of Boeing Alert Requirements Bulletin 737-52A1180 
RB, dated January 24, 2020, is limited to certain Boeing Model 737-600, 
-700, -700C, -800, -900, and -900ER series airplanes. However, the 
applicability of this proposed AD includes all existing and future 
Boeing Model 737 series airplanes, excluding Model 737-100,

[[Page 34138]]

-200, -200C, -300, -400, and -500 series airplanes. Because the 
affected parts are rotable parts, the FAA has determined that these 
parts with the unsafe design could later be installed on airplanes that 
were initially delivered with acceptable parts, thereby subjecting 
those airplanes to the unsafe condition.

Costs of Compliance

    The FAA estimates that this proposed AD would affect 1,075 
airplanes of U.S. registry. The FAA 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
----------------------------------------------------------------------------------------------------------------
Inspection and part replacement..  Up to 4 work-hours           $4,640  Up to $4,980.......  Up to $5,353,500.
                                    x $85 per hour =
                                    Up to $340.
----------------------------------------------------------------------------------------------------------------

    The FAA has included all known costs in the cost estimate. 
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 persons.

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-2020-0459; Product Identifier 
2020-NM-049-AD.

(a) Comments Due Date

    The FAA must receive comments by July 20, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737 series 
airplanes, excluding Model 737-100, -200, -200C, -300, -400, and -
500 series airplanes, certificated in any category.

(d) Subject

    Air Transport Association (ATA) of America Code 52, Doors.

(e) Unsafe Condition

    This AD was prompted by reports of cracked or completely severed 
lugs in the stop fitting assembly of the forward entry door. The FAA 
is issuing this AD to address such cracking or severing, which could 
result in reduced structural integrity of the forward entry door and 
consequent rapid decompression of the airplane.

(f) Compliance

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

(g) Required Actions

    For airplanes having a date of issuance of the original 
airworthiness certificate or date of issuance of the original export 
certificate of airworthiness on before the effective date of this 
AD: Except as specified by paragraph (h) of this AD, at the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 737-52A1180 RB, dated January 24, 2020, 
do all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-52A1180 RB, dated January 24, 2020.

    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-52A1180, dated January 24, 2020, which is referred to in Boeing 
Alert Requirements Bulletin 737-52A1180 RB, dated January 24, 2020.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Requirements Bulletin 737-52A1180 RB, 
dated January 24, 2020, uses the phrase ``the original issue date of 
Requirements Bulletin 737-52A1180 RB,'' this AD requires using ``the 
effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 737-52A1180 RB, 
dated January 24, 2020, 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 (j) of this AD.

(i) Parts Installation Prohibition

    For airplanes on which the actions specified in paragraph (g) of 
this AD have been accomplished, or for airplanes having a date of 
issuance of the original airworthiness certificate or date of 
issuance of the original export certificate of airworthiness dated 
after the effective date of this AD: As of the effective date of 
this AD, no person may install a stop fitting assembly with part 
number 141A6104-3 or a forward entry door that has a stop fitting 
assembly with part number 141A6104-3, on any airplane.

[[Page 34139]]

(j) 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 (k)(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.

(k) Related Information

    (1) For more information about this AD, contact Michael 
Bumbaugh, Aerospace Engineer, Airframe Section, FAA, Seattle ACO 
Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 
206-231-3522; email: michael.bumbaugh@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, 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.

    Issued on May 22, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-11828 Filed 6-2-20; 8:45 am]
BILLING CODE 4910-13-P


