DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0621; Directorate Identifier 2017-NM-049-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 DHC-8-400 series airplanes. This
proposed AD was prompted by reports that operation of fuselage doors
was interrupted due to corrosion in certain door roller bearings. This
proposed AD would require a one-time detailed inspection of the
bearings for corrosion, and replacement if necessary. We are proposing
this AD to address the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by August 7, 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., Q-Series Technical Help Desk, 123 Garratt Boulevard,
Toronto, Ontario M3K 1Y5, Canada; telephone 416-375-4000; fax 416-375-
4539; email thd.qseries@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-2017-0621;
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, FAA, New York Aircraft
Certification Office (ACO), 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 proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include "Docket No. FAA-2017-0621;
Directorate Identifier 2017-NM-049-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-
2016-18, dated June 20, 2016 (referred to after this as the Mandatory
Continuing Airworthiness Information, or "the MCAI"), to correct an
unsafe condition for certain Bombardier, Inc., Model DHC-8-400 series
airplanes. The MCAI states:

A number of translating fuselage door operation interruptions
has been reported. In one case, the Aft Service door could not be
opened. It was found that the door lift latch bearings had corroded,
which prevented the door from opening.

The translating doors are classified as emergency exits. The
inability to open an emergency exit could inhibit evacuation in the
event of an emergency. This [Canadian] AD is issued to mandate a
one-time inspection of the translating door bearings to check for
corrosion, replace bearings if required, and apply Corrosion
Inhibiting Compound (CIC).

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-2017-0621.

Related Service Information Under 1 CFR Part 51

Bombardier has issued Service Bulletin 84-52-88, dated April 14,
2016. This service information describes procedures for identification
of corrosion in fuselage door bearings, replacement if necessary, and
CIC application. 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 the same
type designs.

Costs of Compliance

We estimate that this proposed AD affects 143 airplanes of U.S. registry.

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

Estimated Costs

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

On-Condition 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):