DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0587; Product Identifier 2018-NM-054-AD]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede Airworthiness Directive (AD) 2012-22-
10, which applies to certain Bombardier, Inc., Model CL-600-2C10
(Regional Jet Series 700, 701, & 702) airplanes, Model CL-600-2D15
(Regional Jet Series 705) airplanes, Model CL-600-2D24 (Regional Jet
Series 900) airplanes, and Model CL-600-2E25 (Regional Jet Series 1000)
airplanes. AD 2012-22-10 requires repetitive inspections to determine
that cotter pins are installed at affected wing-to-fuselage attachment
joints and replacement if necessary. Since we issued AD 2012-22-10, we
determined that additional nuts of the forward keel beam attachment
joint should be inspected, and that repetitive inspections of certain
wing-to-fuselage attachment joints are not necessary. This proposed AD
would retain the initial inspection of the wing-to-fuselage attachment
joints, and remove the repetitive inspections of all but the forward
keel beam attachment joint. This proposed AD would also change the
repetitive inspection interval for the forward keel beam attachment
joint. We are proposing this AD to address the unsafe condition on
these products.

DATES: We must receive comments on this proposed AD by August 23, 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
Bombardier, Inc., 400 Cote-Vertu Road West, Dorval, Quebec
H4S 1Y9, Canada; Widebody Customer Response Center North America toll-
free telephone 1-866-538-1247 or direct-dial telephone 514-855-5000;
fax 514-855-7401; email ac.yul@aero.bombardier.com; internet http://
www.bombardier.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.

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-2018-0587;
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 Operations
office (telephone 800-647-5527) is in the ADDRESSES section. Comments
will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Aziz Ahmed, Aerospace Engineer,
Airframe and Mechanical Systems Section, FAA, New York ACO Branch, 1600
Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7329;
fax 516-794-5531.

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-2018-0587;
Product Identifier 2018-NM-054-AD" at the beginning of your comments.
We specifically invite comments on the overall regulatory, economic,
environmental, and energy aspects of this proposed AD. We will consider
all comments received by the closing date and may amend this proposed
AD based on 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.

Discussion

We issued AD 2012-22-10, Amendment 39-17246 (77 FR 67267, November
9, 2012) ("AD 2012-22-10"), for certain Bombardier, Inc., Model CL-
600-2C10 (Regional Jet Series 700, 701, & 702) airplanes, Model
CL-600-2D15 (Regional Jet Series 705) airplanes, Model CL-600-2D24
(Regional Jet Series 900) airplanes, and Model CL-600-2E25 (Regional Jet
Series 1000) airplanes. AD 2012-22-10 requires repetitive inspections to
determine that cotter pins are installed at affected wing-to-fuselage
attachment joints and replacement if necessary. AD 2012-22-10 resulted
from a report that certain wing-to-fuselage attachment nuts do not conform
to the certification design requirements for dual locking features. We
issued AD 2012-22-10 to prevent loss of wing-to-fuselage attachment
joints, which could result in the loss of the wing.

Actions Since AD 2012-22-10 Was Issued

Since we issued AD 2012-22-10, we determined that additional nuts
of the forward keel beam attachment joint should be inspected, and that
repetitive inspections of certain wing-to-fuselage attachment joints
are not necessary.

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, issued Canadian AD CF-2012-10R1, dated January
22, 2018 (referred to after this as the Mandatory Continuing
Airworthiness Information, or "the MCAI"), to correct an unsafe
condition for certain Bombardier, Inc., Model CL-600-2C10 (Regional Jet
Series 700, 701, & 702) airplanes, Model CL-600-2D15 (Regional Jet
Series 705) airplanes, Model CL-600-2D24 (Regional Jet Series 900)
airplanes, and Model CL-600-2E25 (Regional Jet Series 1000) airplanes.
The MCAI states:

The manufacturer has determined that wing-to-fuselage attachment
nuts, part number (P/N) SH670-35635-1, SH670-35440-951, SH670-35440-
3, SH670-35635-1, and 95136D-2412, installed at six attachment joint
locations, do not conform to the certification design requirements
for dual locking features. The nuts are not of the self-locking type
as required and do not provide the frictional thread interference
required to prevent the nut from backing off the bolt. As a result,
only a single locking device, the cotter pin, is provided at these
critical joints. In the case where a nut becomes loose, in
combination with a missing or broken cotter pin, the attachment bolt
at the wing-to-fuselage joint could migrate and fall out. Loss of
two attachment joints could potentially result in the loss of the
wing.

The original version of this [Canadian] AD [which corresponds to
FAA AD 2012-22-10] mandated initial and repeat detailed visual
inspections (DVIs) of each affected wing-to-fuselage attachment
joint to ensure that a cotter pin was installed.

Design review and analysis of the inspection findings since the
original issue of this [Canadian] AD have led us to determine that
additional nuts at the forward keel beam joint should also be
included in the inspection and that the repetitive inspection of
some wing-to-fuselage attachment joints is not required. This
[Canadian] AD maintains the initial inspection requirements [for
missing or failed (. . .) cotter pins] for six attachment joint
locations, and removes the repetitive inspection requirements for
all but the forward keel beam attachment joint. This [Canadian] AD
also requires a different repetitive inspection interval, and the
[Canadian] AD applicability has been changed for the initial
inspection to account for changes made in production.

Related Service Information Under 1 CFR Part 51

Bombardier, Inc. has issued Service Bulletin 670BA-53-042, Revision
B, dated October 20, 2017. This service information describes
procedures for detailed inspections of the wing-to-fuselage attachment
joints, and of the attachment nuts at the forward keel beam attachment
joint for missing or failed cotter pins. 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 and Requirements of This Proposed AD

This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to our bilateral agreement with the State of Design Authority, we have
been notified of the unsafe condition described in the MCAI and service
information referenced above. We are proposing this AD because we
evaluated all pertinent information and determined an unsafe condition
exists and is likely to exist or develop on other products of these
same type design.

Costs of Compliance

We estimate that this proposed AD affects 274 airplanes of U.S.
registry. We estimate the following costs to comply with this proposed
AD:

Estimated Costs for Required Actions

We have received no definitive data that would enable us to provide
cost estimates for the on-condition actions specified in this proposed
AD. We have no way of determining the number of aircraft that may need
these actions.

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

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)
2012-22-10, Amendment 39-17246 (77 FR 67267, November 9, 2012), and
adding the following new AD: