DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0965; Product Identifier 2018-NM-124-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 adopt a new airworthiness directive (AD) for
certain Bombardier, Inc., Model BD-100-1A10 airplanes. This proposed AD
was prompted by a report that certain split ball bearings used in main
landing gear (MLG) side brace actuator assemblies are manufactured from
material that does not meet the required material properties. This
proposed AD would require an inspection of the left and right MLG side
brace actuator assembly and, if necessary, replacement of the split
ball bearing. We are proposing this AD to address the unsafe condition
on these products.

DATES: We must receive comments on this proposed AD by January 14, 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 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; telephone 514-855-5000; fax 514-855-7401; email
thd.crj@aero.bombardier.com; internet http://www.bombardier.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.

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-2018-0965;
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 (phone: 800-647-
5527) is in the ADDRESSES section. Comments will be available in the AD
docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Darren Gassetto, Aerospace Engineer,
Mechanical Systems and Admin Services Section, FAA, New York ACO
Branch, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; telephone
516-228-7323; fax 516-794-5531; email 9-avs-nyaco-cos@faa.gov.

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-2018-0965;
Product Identifier 2018-NM-124-AD" at the beginning of your comments.
We specifically invite comments on the overall regulatory, economic,
environmental, and energy aspects of this NPRM. We will consider all
comments received by the closing date and may amend this NPRM because
of 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 NPRM.

Discussion

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian AD CF-2018-20, dated July 27,
2018 (referred to after this as the Mandatory Continuing Airworthiness
Information, or "the MCAI"), to correct an unsafe condition for
certain Bombardier, Inc., Model BD-100-1A10 airplanes. The MCAI states:

The landing gear supplier has informed Bombardier Aerospace
about a quality escape involving Main Landing Gear (MLG) side brace
actuators that have been assembled using non-conforming split ball
bearings. The affected bearings are manufactured from material that
does not meet the required material properties. If not corrected,
this condition can result in potentially asymmetric MLG gear
extension or retraction and subsequent gear collapse during landing.

This AD mandates verification of the installed MLG side brace
actuator assemblies and replacement of the affected parts.

You may examine the MCAI in the AD docket on the internet at http://www.
regulations.gov by searching for and locating Docket No. FAA-2018-0965.

Related Service Information Under 1 CFR Part 51

Bombardier, Inc., has issued Service Bulletin 100-32-30, dated
December 18, 2017, and Service Bulletin 350-32-006, dated December 18,
2017. The service information describes procedures to perform an
inspection of the left and right MLG side brace actuator assembly to
verify the serial number and replacement of the split ball bearing.
These documents are distinct since they apply to airplanes in different
configurations. 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

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 the relevant information and determined
the unsafe condition described previously is likely to exist or develop
on other products of the same type design.

Proposed Requirements of This NPRM

This proposed AD would require accomplishing the actions specified
in the service information described previously.

Costs of Compliance

We estimate that this proposed AD affects 468 airplanes of U.S.
registry. We estimate the following costs to comply with this proposed
AD:

Estimated Costs for Required Actions

We estimate the following costs to do any necessary on-condition
actions that would be required based on the results of the required
inspection. We have no way of determining the number of aircraft that
might need this on-condition actions:

Estimated Costs of On-Condition Actions

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. We do not control warranty coverage for
affected individuals. As a result, we have included all known costs in
our 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.

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 adding the following new airworthiness
directive (AD):