DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0322; Product Identifier 2019-NM-039-AD]
RIN 2120-AA64

Airworthiness Directives; Bombardier, Inc., Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

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 of cracked elevator power control
unit (PCU) brackets on the horizontal stabilizer rear spar and cracking
on the elevator front spar. This proposed AD would require one-time
inspections for cracks and damage of the elevator PCU brackets and
surrounding area, horizontal stabilizer rear spar, and elevator front
spar, and related investigative and corrective actions 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 June 28, 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., 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 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-2019-0322;
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 listed above. Comments will be available in the AD docket
shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Andrea Jimenez, Aerospace Engineer,
Airframe and Mechanical Systems Section, FAA, New York ACO Branch, 1600
Stewart Avenue, Suite 410, Westbury, NY 11590; telephone 516-228-7330;
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-2019-0322;
Product Identifier 2019-NM-039-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-2018-34, dated December
17, 2018 (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:

There have been five in-service reports of cracked elevator
power control unit (PCU) brackets on the horizontal stabilizer rear
spar, and two reports of cracking on the elevator front spar. In one
case, the PCU bracket cracking led to detachment of the bracket
during pushback. An investigation found that the force-fight loads
induced by elevator PCUs not rigged to the required tolerance is the
common factor in cracking of both the elevator PCU bracket and of
the elevator front spar. A secondary contributor to the elevator PCU
bracket cracking is the bracket flange preload that may be induced
during production installation. Failure of an elevator PCU bracket
or progression of the elevator front spar cracking into two segments
may cause the affected elevator to jam. Failure of an elevator
bracket on both elevators, or progression of elevator front spar
cracking into two segments on both elevators, could cause a loss of
aeroplane pitch control.

This [Canadian] AD mandates a one-time inspection of the
elevator PCU brackets, the horizontal stabilizer rear spar and
elevator front spar with reporting of inspection findings. Any
brackets found cracked are to be replaced with new brackets with
improved strength. For any spar found cracked, obtain instructions
to repair the spar from Bombardier and repair the spar accordingly.
Additional corrective action may be considered depending on the
results of the inspections findings.

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-2019-
0322.

Related Service Information Under 1 CFR Part 51

Bombardier has issued Service Bulletin 84-55-09, dated June 7,
2018. This service information describes procedures for one-time
detailed visual and fluorescent penetrant inspections for cracks and
damage of the elevator PCU brackets (including the surrounding area),
horizontal stabilizer rear spar, and elevator front spar, and related
investigative and corrective actions if necessary. The related
investigative action is an eddy current inspection for cracking of
certain mating holes of the horizontal stabilizer rear spar. Corrective
actions include replacement of the elevator PCU brackets and repair of
the horizontal stabilizer rear spar and elevator front spar.

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. This proposed AD also
would require sending the inspection results to Bombardier.

Costs of Compliance

We estimate that this proposed AD affects 54 airplanes of U.S.
registry. We estimate the following costs to comply with this proposed
AD:

Estimated Costs for Required Actions *

* Table does not include estimated costs for reporting.

We estimate that it would take about 1 work-hour per product to
comply with the proposed reporting requirement in this proposed AD. The
average labor rate is $85 per hour. Based on these figures, we estimate
the cost of reporting the inspection results on U.S. operators to be
$4,590, or $85 per product.

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

Estimated Costs of On-Condition Actions

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a current valid OMB control number. The control
number for the collection of information required by this NPRM is 2120-
0056. The paperwork cost associated with this NPRM has been detailed in
the Costs of Compliance section of this document and includes time for
reviewing instructions, as well as completing and reviewing the
collection of information. Therefore, all reporting associated with
this NPRM is mandatory. Comments concerning the accuracy of this burden
and suggestions for reducing the burden should be directed to the FAA
at 800 Independence Ave. SW, Washington, DC 20591, ATTN: Information
Collection Clearance Officer, AES-200.

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 and associated appliances 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):