Document ID: FAA-2021-0788-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2021-10-13T04:00Z

[Federal Register Volume 86, Number 195 (Wednesday, October 13, 2021)]
[Proposed Rules]
[Pages 56840-56843]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-22203]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0788; Project Identifier AD-2021-00489-T]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain The Boeing Company Model 737-700, -800, and -900ER series 
airplanes. This proposed AD was prompted by reports of incorrectly 
installed fuselage skin fasteners. This proposed AD would require a 
detailed inspection of a certain body station bulkhead, between certain 
stringers, for any incorrectly installed fastener common to fuselage 
skin, 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 November 
29, 2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR

[[Page 56841]]

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, 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-
0788.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0788; 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.

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

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2021-0788; Project Identifier 
AD-2021-00489-T'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. The FAA 
will consider all comments received by the closing date and may amend 
this proposal 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 agency will also post a report summarizing each 
substantive verbal contact received about this NPRM.

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 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]. Any commentary that the FAA receives which is not 
specifically designated as CBI will be placed in the public docket for 
this rulemaking.

Background

    The FAA has received a report indicating incorrectly installed 
fasteners were found at the station (STA) 727 bulkhead between 
stringers S-22 and S-27. The fasteners, installed with a gap under the 
fastener head, were found at the STA 727 bulkhead common to fuselage 
skin, including the S-23 skin lap splice. Incorrectly installed 
fasteners are suspected to exist on airplanes delivered within a 
certain time period. The FAA has confirmed that the fastener 
installation procedures were corrected on airplanes subsequently 
delivered. This condition was the result of incorrect procedures used 
to install affected fasteners during airplane production, which could 
result in incorrectly installed fasteners going undetected. Continuous 
operation of the airplane with incorrectly installed fasteners may 
generate fatigue cracking that could adversely affect the structural 
integrity of the airplane. Gaps under fastener heads will result in 
bending loads on the bulkhead chord that could cause chord failure and 
adjacent skin failure, resulting in reduced control of the airplane.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 737-53A1384 RB, 
dated September 10, 2020. This service information specifies procedures 
for a detailed inspection for incorrectly installed fasteners at the 
STA 727 bulkhead outer chord common to the fuselage skin between 
stringers S-22 and S-27 on the left and right sides, and applicable on-
condition actions. In addition to repair and replacement, on-condition 
actions include repetitive inspections for cracking of the fuselage 
skin between stringers S-22 and S-27; an open hole high frequency eddy 
current (HFEC) inspection for cracking at all incorrectly installed 
fastener locations; and external and internal general visual 
inspections for repairs of the STA 727 bulkhead. On-condition actions 
also include repetitive HFEC and low frequency eddy current (LFEC) 
inspections in unrepaired areas for cracking of the inner skin from the 
wheel well; of the outer, upper, and lower chords from the wheel well; 
and of the fail-safe chord from the cargo compartment.
    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.

Proposed AD Requirements in This NPRM

    This proposed AD would require accomplishing the actions specified 
in the service information already described 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-2021-0788.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 78 airplanes of U.S. registry. The FAA estimates the following 
costs to comply with this proposed AD:

[[Page 56842]]

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
               Action                         Labor cost            Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Inspections........................  13 work-hours x $85 per                  $0          $1,105         $86,190
                                      hour = $1,105.
----------------------------------------------------------------------------------------------------------------

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

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                Action                            Labor cost              Parts cost        Cost per product
----------------------------------------------------------------------------------------------------------------
Open hole HFEC inspections............  21 work-hours x $85 per hour =              $0  $1,785 per inspection
                                         $85 per inspection cycle.                       cycle.
HFEC and LFEC inspections.............  36 work-hours x $85 per hour =               0  3,060 per inspection
                                         $3,060 per inspection cycle.                    cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some or all of the costs of 
this proposed 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

    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) Would not affect intrastate aviation in Alaska, and
    (3) Would 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:

The Boeing Company: Docket No. FAA-2021-0788; Project Identifier AD-
2021-489-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by November 29, 2021.

(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, and identified 
in Boeing Alert Requirements Bulletin 737-53A1384 RB, dated 
September 10, 2020.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of incorrectly installed 
fuselage skin fasteners. The FAA is issuing this AD to address 
incorrectly installed fasteners. This condition, if not addressed, 
could result in incorrectly installed fasteners going undetected. 
Continuous operation of the airplane with undetected incorrectly 
installed fasteners may generate fatigue cracking that could 
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 737-53A1384 RB, dated September 10, 
2020, do all applicable actions identified in, and in accordance 
with, the Accomplishment Instructions of Boeing Alert Requirements 
Bulletin 737-53A1384 RB, dated September 10, 2020.

    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-53A1384, dated September 10, 2020, which is referred to in 
Boeing Alert Requirements Bulletin 737-53A1384 RB, dated September 
10, 2020.

(h) Exceptions to Service Information Specifications

    (1) Where the ``Effectivity'' paragraph and the Condition and 
Compliance Time columns of the tables in the ``Compliance'' 
paragraph of Boeing Alert Requirements Bulletin 737-53A1384 RB, 
dated September 10, 2020, use the phrase ``the Original Issue date 
of Requirements Bulletin 737-53A1384 RB,'' this AD requires using 
``the effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 737-53A1384 RB, 
dated September 10, 2020, specifies contacting Boeing for

[[Page 56843]]

repair instructions or for alternative inspections: This AD requires 
doing the repair, or doing the alternative inspections and 
applicable on-condition 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 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 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 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.

(j) 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 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 September 9, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-22203 Filed 10-12-21; 8:45 am]
BILLING CODE 4910-13-P