DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-1246; Product Identifier 2017-NM-086-AD]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc.

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede Airworthiness Directive (AD) 2014-02-
01, which applies to certain Bombardier, Inc., Model CL-600-2C10
(Regional Jet Series 700, 701, & 702), Model CL-600-2D15 (Regional Jet
Series 705), and Model CL-600-2D24 (Regional Jet Series 900) airplanes.
AD 2014-02-01 requires repetitive inspections of the rudder travel
limiter (RTL) return springs and primary actuator, and corrective
actions if necessary; and replacement of certain RTL return springs.
Since we issued AD 2014-02-01, we received reports that when installing
the RTL return springs, the RTL limiter arm assembly lug can become
deformed. This proposed AD would require an inspection of the RTL
return springs for signs of chafing; an inspection of the casing of the
primary actuator for signs of chafing or missing paint; replacement of
the RTL return springs; and an inspection of the lugs of the RTL
limiter arm assembly for cracks, and modification or replacement, as
applicable; and applicable corrective actions. This proposed AD would
also add airplanes to the applicability. We are proposing this AD to
address the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by March 2, 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: 1-514-855-2999; 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, 1601 Lind Avenue SW, Renton, WA. For information on the avail-
ability of this material at the FAA, call 425-227-1221.

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-2017-1246;
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 proposed AD, 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: Cesar Gomez, Aerospace Engineer,
Airframe and Mechanical Systems Section, FAA, New York ACO Branch, 1600
Stewart Avenue, Suite 410, Westbury, NY 11590; telephone: 516-228-7318;
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-2017-1246;
Product Identifier 2017-NM-086-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 2014-02-01, Amendment 39-17729 (79 FR 7382, February
7, 2014) ("AD 2014-02-01"), for certain Bombardier, Inc., Model CL-
600-2C10 (Regional Jet Series 700, 701, & 702), Model CL-600-2D15
(Regional Jet Series 705), and Model CL-600-2D24 (Regional Jet Series
900) airplanes. AD 2014-02-01 was prompted by reports of failure of the
RTL return spring. AD 2014-02-01 requires repetitive inspections of the
RTL return springs and primary actuator, and corrective actions if
necessary; and replacement of certain RTL return springs, including
related investigative and corrective actions, if necessary. We issued
AD 2014-02-01 to prevent failure of the RTL, which would permit an
increase of rudder authority beyond normal structural limits and
consequently affect the controllability of the airplane.

Since we issued AD 2014-02-01, we received reports that when
installing RTL return spring part number BA670-93468-1, the RTL limiter
arm assembly lugs can become deformed when the RTL return spring
attachment bolt is torqued. We have also determined that additional
airplanes are affected by the unsafe condition.

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian AD CF-2017-19, dated June 6,
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), Model CL-600-2D15 (Regional Jet Series 705), and Model CL-
600-2D24 (Regional Jet Series 900) airplanes. The MCAI states:

Transport Canada AD CF-2010-18R1 [which corresponds to FAA AD
2014-02-01] mandated a repetitive inspection and introduced a new
rudder travel limiter (RTL) return spring, part number (P/N) BA670-
93468-1, to correct the potential dormant RTL spring failure. This
[Canadian] AD is issued to supersede the repetitive inspection and
the replacement of the RTL spring due to discoveries made after the
issuance of [Canadian] AD CF-2010-18R1.

When installing the RTL return spring P/N BA670-93468-1 as
mandated by [Canadian] AD CF-2010-18R1, it was found that it is
possible for the RTL limiter arm assembly lug to be deformed. The
lugs become bent when the RTL return spring attachment bolt is
torqued. This condition, if not corrected, can lead to failure of
the limiter arm assembly lug. In combination with failure of the
RTL, failure of the limiter arm assembly lug could affect the
controllability of the aeroplane.

This [Canadian] AD mandates the inspection for cracked RTL limiter arm
lugs and modification of the RTL limiter arm to prevent the RTL limiter
arm lugs from bending during RTL assembly.

Required actions include: A detailed visual inspection of the RTL
return springs for signs of chafing; a detailed visual inspection of
the casing of the primary actuator for signs of chafing or missing
paint; replacement of the RTL return springs; an eddy current
inspection of the lugs of the RTL limiter arm assembly for cracks, and
modification or replacement of the RTL limiter arm assembly, as
applicable; and applicable corrective actions. Corrective actions
include: replacement of the RTL return springs, repair of the primer
and topcoat of the primary actuator, and replacement of the primary
actuator. 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-2017-1246.

Related Service Information Under 1 CFR Part 51

Bombardier, Inc., has issued Bombardier Service Bulletin 670BA-27-
070, Revision B, dated March 31, 2017. The service information
describes procedures for an inspection of the RTL return springs for
signs of chafing; an inspection of the casing of the primary actuator
for signs of chafing or missing paint; replacement of the RTL return
springs; and an inspection of the lugs of the RTL limiter arm assembly
for cracks, and modification or replacement, as applicable; and
applicable corrective actions. 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 designs.

Costs of Compliance

We estimate that this proposed AD affects 544 airplanes of U.S. registry.

We estimate that it would take about 16 work-hours per product to
comply with the basic requirements of this proposed AD. The average
labor rate is $85 per work-hour. Required parts would cost about $2,960
per product. Based on these figures, we estimate the cost of this
proposed AD on U.S. operators to be $2,350,080, or $4,320 per product.

We have received no definitive data that would enable us to provide
cost estimates for the on-condition actions specified in this proposed
AD.

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 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)
2014-02-01, Amendment 39-17729 (79 FR 7382, February 7, 2014), and
adding the following new AD: