DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0866; Product Identifier 2019-NM-174-AD; Amendment
39-19789; AD 2019-22-10]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2019-20-
02, which applied to all The Boeing Company Model 737-600, -700, -700C,
-800, -900, and -900ER series airplanes. AD 2019-20-02 required
repetitive inspections for cracking of the left- and right-hand side
outboard chords of frame fittings and failsafe straps at a certain
station around two fasteners, and repair if any cracking is found. This
AD also requires repetitive inspections for cracking of the left- and
right-hand side outboard chords of frame fittings and failsafe straps
at a certain station, but expands the inspection to the area around
eight fasteners, and also requires repair if any cracking is found.
This AD was prompted by a determination that the inspection area needs
to be expanded. The FAA is issuing this AD to address the unsafe
condition on these products.

DATES: This AD is effective November 13, 2019.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of November 13,
2019.
The Director of the Federal Register approved the incorporation by
reference of a certain other publication listed in this AD as of
October 3, 2019 (84 FR 52754, October 3, 2019).
The FAA must receive any comments on this AD by December 30, 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 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 final rule, 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 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-2019-0866.

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-2019-
0866; 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 final rule, 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: Greg.Rutar@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

The FAA issued AD 2019-20-02, Amendment 39-19755 (84 FR 52754,
October 3, 2019) (``AD 2019-20-02''), for all The Boeing Company Model
737-600, -700, -700C, -800, -900, and -900ER series airplanes. AD 2019-
20-02 required repetitive inspections for cracking of the left- and
right-hand side outboard chords of frame fittings and failsafe straps
at a certain station around two fasteners, and repair if any cracking
is found. AD 2019-20-02 was prompted by reports of cracking in this
area found on multiple Boeing Model 737-800 airplanes during a
passenger-to-freighter conversion. The FAA issued AD 2019-20-02 to
address this cracking, which could result in failure of a Principal
Structural Element (PSE) to sustain limit load. This condition could
adversely affect the structural integrity of the airplane, and result
in loss of control of the airplane.

Actions Since AD 2019-20-02 Was Issued

Since AD 2019-20-02 was issued, the FAA has reviewed inspection
findings submitted as required by paragraph (h) of AD 2019-20-02. From
these findings, four airplanes have been identified to have cracking
outside the initial inspection area. Based on these findings, the FAA
has determined that the inspection area must be expanded from the area
around two fasteners to the area around eight fasteners on both the
left- and right-hand sides (which includes the area around the two
fasteners inspected as required by AD 2019-20-02) to adequately address
the unsafe condition.
The FAA has taken all inspection findings into consideration in
assessing the merits of the existing regulatory action. The findings
support that the initial inspection thresholds are adequate to ensure
fleet safety. All airplane structure has an initial period when fatigue
cracking is not anticipated. Beyond this period, structural safety can
be maintained with a damage-tolerant design and inspection program. The
compliance times for the initial and repetitive inspections as
specified in paragraph (g) of AD 2019-20-02 were determined using
standard damage tolerance principles. Residual strength is the load
that damaged (cracked) structure can still carry without failing.
Structure is damage-tolerant if damage that may occur can be detected
and repaired before the residual strength capability falls below the
minimum residual strength required under Title 14 Code of Federal
Regulations (14 CFR) 25.571.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Boeing Multi-Operator Message MOM-MOM-19-0623-01B,
dated November 5, 2019. This service information describes procedures
for repetitive detailed inspections for cracking of the left- and
right-hand side outboard chords of the station (STA) 663.75 frame
fittings and failsafe straps around eight fasteners adjacent to the
stringer S-18A straps.
This AD also requires Boeing Multi-Operator Message MOM-MOM-19-
0536-01B, dated September 30, 2019, which the Director of the Federal
Register approved for incorporation by reference as of October 3, 2019
(84 FR 52754, October 3, 2019).
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 issuing 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.

AD Requirements

This AD requires repetitive inspections for cracking of the left-
and right-hand side outboard chords of the STA 663.75 frame fittings
and failsafe straps around eight fasteners adjacent to the stringer S-
18A straps. This AD also requires repair of all cracking using a method
approved by the FAA or The Boeing Company Organization Designation
Authorization (ODA). Accomplishing the initial inspection required by
paragraph (i) of this AD terminates the inspections originally required
by AD 2019-20-02 and retained in this AD. This AD also requires sending
a report of all results of the initial inspections to Boeing.

Interim Action

The FAA considers this AD interim action. The inspection reports
that are required by this AD will enable the manufacturer to obtain
better insight into the nature, cause, and extent of the cracking, and
eventually to develop final action to address the unsafe condition.
Once final action has been identified, the FAA might consider further
rulemaking.

Justification for Immediate Adoption and Determination of the Effective
Date

Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5
U.S.C.) authorizes agencies to dispense with notice and comment
procedures for rules when the agency, for ``good cause,'' finds that
those procedures are ``impracticable, unnecessary, or contrary to the
public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without seeking comment prior to the
rulemaking. Similarly, Section 553(d) of the APA authorizes agencies to
make rules effective in less than thirty days, upon a finding of good
cause.
An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies forgoing notice and comment prior to adoption of this rule
because cracking in the STA 663.75 frame fitting outboard chords and
failsafe straps around eight fasteners adjacent to the stringer S-18A
straps could result in failure of a PSE to sustain limit load. This
condition could adversely affect the structural integrity of the
airplane and result in loss of control of the airplane. The compliance
time for the required action is shorter than the time necessary for the
public to comment and for publication of the final rule.
Accordingly, notice and opportunity for prior public comment are
impracticable and contrary to the public interest pursuant to 5 U.S.C.
553(b)(3)(B). In addition, for the reasons stated above, the FAA finds
that good cause exists pursuant to 5 U.S.C. 553(d) for making this
amendment effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements affecting flight
safety and was not preceded by notice and an opportunity for public
comment. However, the FAA invites you to send any written data, views,
or arguments about this final rule. Send your comments to an address
listed under the ADDRESSES section. Include the docket number FAA-2019-
0866 and Product Identifier 2019-NM-174-AD at the beginning of your
comments. The FAA specifically invites comments on the overall
regulatory, economic, environmental, and energy aspects of this final
rule. The FAA will consider all comments received by the closing date
and may amend this final rule 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 final rule.

Regulatory Flexibility Act

The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
a rule without prior notice and comment. Because the FAA has determined
that it has good cause to adopt this rule without notice and comment,
RFA analysis is not required.

Costs of Compliance

The FAA estimates that this AD affects 1,911 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:

Estimated Costs

The FAA has received no definitive data that would enable the
agency to provide cost estimates for the on-condition actions specified
in this AD.

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a current valid OMB control number. The control
number for the collection of information required by this AD is 2120-
0056. The paperwork cost associated with this AD has been detailed in
the Costs of Compliance section of this document and includes time for
reviewing instructions, as well as completing and reviewing the
collection of information. Therefore, all reporting associated with
this AD is mandatory. Comments concerning the accuracy of this burden
and suggestions for reducing the burden should be directed to
Information Collection Clearance Officer, Federal Aviation
Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177-1524.

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 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 has determined that this AD will not have federalism
implications under Executive Order 13132. This AD will 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 that this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866, and
(2) Will not affect intrastate aviation in Alaska.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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]

2. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD)
2019-20-02, Amendment 39-19755 (84 FR 52754, October 3, 2019), and
adding the following new AD: