DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0338; Directorate Identifier 2016-NM-153-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 CL-600-2A12 (CL-601 Variant) and CL-
600-2B16 (CL-601-3A, CL-601-3R, and CL-604 Variants) airplanes. This
proposed AD was prompted by a determination that the bushing holes on
the engine mount rib might not conform to the engineering drawings and
that certain inspections of the engine mount rib must be included in
the airworthiness limitations section (ALS) of the Instructions for
Continued Airworthiness (ICA). This proposed AD would require revising
the maintenance or inspection program to incorporate certain
airworthiness limitation items (ALIs). We are proposing this AD to
address the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by July 31, 2017.

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 C[ocirc]te-Vertu Road West, Dorval, Qu[eacute]bec
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 Airplane Directorate, 1601 Lind Avenue SW., Renton,
WA. For information on the availability 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-2017-0338; 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: Aziz Ahmed, Aerospace Engineer,
Airframe and Mechanical Systems Branch, ANE-171, New York Aircraft
Certification Office (ACO), FAA, 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-2017-0338;
Directorate Identifier 2016-NM-153-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

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian Airworthiness Directive CF-
2015-09R1, dated June 29, 2015 (referred to after this as the Mandatory
Continuing Airworthiness Information, or "the MCAI"), to correct an
unsafe condition for certain Bombardier, Inc., Model CL-600-2A12 (CL-
601 Variant), and CL-600-2B16 (CL-601-3A, CL-601-3R, and CL-604
Variants) airplanes. The MCAI states:

The aeroplane manufacturer has determined that the bushing holes
on the engine mount rib may not conform to the engineering drawings.
Non-conforming bushing holes could increase loading on adjacent
fasteners, resulting in premature fatigue cracking of the engine
mount rib.

In addition, it was also discovered that the inspection
requirements for the engine mount rib were not listed in the
Airworthiness Limitations Section of the Instructions for Continued
Airworthiness.

Failure of the engine mount rib could compromise the structural
integrity of the engine mount and could lead to subsequent
detachment of an engine.

A new Time Limits/Maintenance Checks (TLMC) Airworthiness
Limitations (AWL) task is introduced to ensure that any fatigue
cracking of the engine mount rib is detected and corrected.

The original issue of this [Canadian] AD mandated the
incorporation of a new TLMC AWL task [into the maintenance or
inspection program, as applicable].

Revision 1 of this [Canadian] AD is issued to remove model CL-
600-1A11 (600) aeroplanes from the Applicability section of the
[Canadian] AD since this model was incorrectly included in the
original issue.

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-2017-0338.

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 the same
type design.

This AD requires revisions to certain operator maintenance
documents to include new actions (e.g., inspections). Compliance with
these actions is required by 14 CFR 91.403(c). For airplanes that have
been previously modified, altered, or repaired in the areas addressed
by this proposed AD, the operator may not be able to accomplish the
actions described in the revisions. In this situation, to comply with
14 CFR 91.403(c), the operator must request approval for an alternative
method of compliance under the provisions of paragraph (i)(1) of this
proposed AD. The request should include a description of changes to the
required actions that will ensure the continued damage tolerance of the
affected structure.

Costs of Compliance

We estimate that this proposed AD affects 129 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

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.

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).