DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0551; Product Identifier 2018-NM-023-AD; Amendment
39-19485; AD 2018-22-12]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc. Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) 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. This AD was prompted by
reports of damage to the protective coating and corrosion on the
piston/axle of the main landing gear (MLG), caused by friction between
the inboard axle sleeve and the axle thrust face. This AD requires
revising the maintenance or inspection program, as applicable, to
incorporate a detailed inspection of the MLG piston/axle for damage to
the protective coating and for corrosion. We are issuing this AD to
address the unsafe condition on these products.

DATES: This AD is effective December 12, 2018.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of December 12,
2018.

ADDRESSES: For service information identified in this final rule,
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 1-
514-855-2999; fax 514-855-7401; email ac.yul@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. It is also available on the
internet at http://www.regulations.gov by searching for and locating
Docket No. FAA-2018-0551.

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-
0551; 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 address for Docket Operations (phone: 800-647-
5527) is U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE,
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Darren Gassetto, Aerospace Engineer,
Mechanical Systems and Administrative 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:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 by adding an AD that would apply 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. The NPRM published in the Federal
Register on July 6, 2018 (83 FR 31504). The NPRM was prompted by
reports of damage to the protective coating and corrosion on the
piston/axle of the MLG, caused by friction between the inboard axle
sleeve and the axle thrust face. The NPRM proposed to require revising
the maintenance or inspection program, as applicable, to incorporate a
detailed inspection of the MLG piston/axle for damage to the protective
coating and for corrosion.
We are issuing this AD to address damage to the protective coating
and corrosion found on the piston/axle of the MLG, caused by friction
between the inboard axle sleeve and the axle thrust face, which could
cause the axle to separate from the piston/axle, and ultimately lead to
collapse of the landing gear during ground maneuvers or upon landing.
Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian AD CF-2017-38, dated December
20, 2017 (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:

There have been reports of damage to the protective coating and/
or corrosion on the piston/axle of the Main Landing Gear (MLG). The
damage to the protective coating was caused by friction between the
inboard axle sleeve and the axle thrust face. If not corrected, this
condition can cause the axle to separate from the piston/axle [and
consequent collapse of the landing gear during ground maneuvers or
upon landing].
This [Canadian] AD mandates the incorporation of a new
maintenance task in order to perform a [detailed] visual inspection
of the piston/axle of the MLG to prevent the axle separation from
the piston/axle.

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-
0551.

Comments

We gave the public the opportunity to participate in developing
this final rule. The following presents the comments received on the
NPRM and the FAA's response to each comment.

Support for the NPRM

The Air Line Pilots Association, International and Endeavor Air
stated their support for the proposed AD.

Request To Refer to Certain Revised Service Information

Endeavor Air noted that Bombardier, Inc. has issued certain revised
service information and requested that the proposed AD be updated to
reference the revised service information.
We agree with the commenter's request. We have determined the
revised service information should be referenced in regards to
calculating the time since piston/axle entry into service, since
operators might have done the latest inspection, restoration, or repair
using the revised service information. We have updated paragraph (h) of
this AD to refer to the revised service information and reorganized
paragraph (h) of this AD for consistency.

Conclusion

We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
this final rule with the changes described previously and minor
editorial changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM.
We also determined that these changes will not increase the
economic burden on any operator or increase the scope of this final
rule.

Related Service Information Under 1 CFR Part 51

Bombardier, Inc. has issued CRJ Series Regional Jet Temporary
Revision (TR) MRB-0059, dated March 20, 2015. The service information
describes an airworthiness limitation task for a detailed inspection
for damage to the protective coating and for corrosion on the piston/
axle of the MLG. 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.

Costs of Compliance

We estimate that this AD affects 530 airplanes of U.S. registry. We
estimate the following costs to comply with this AD:
We have determined that revising the maintenance or inspection
program takes an average of 90 work-hours per operator, although we
recognize that this number may vary from operator to operator. In the
past, we have estimated that this action takes 1 work-hour per
airplane. Since operators incorporate maintenance or inspection program
changes for their affected fleet(s), we have determined that a per-
operator estimate is more accurate than a per-airplane estimate.
Therefore, we estimate the total cost per operator to be $7,650 (90
work-hours x $85 per work-hour).

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 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

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,
(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.

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 adding the following new airworthiness
directive (AD):