DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-8434; Product Identifier 2015-NM-082-AD; Amendment
39-19057; AD 2017-19-27]
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 DHC-8-401 and -402 airplanes. This AD was
prompted by the discovery of cracking on two test spoiler power control
unit (PCU) manifolds during testing by the manufacturer. This AD
requires replacement of affected spoiler PCUs. We are issuing this AD
to address the unsafe condition on these products.

DATES: This AD is effective November 1, 2017.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of November 1,
2017.

ADDRESSES: For Bombardier, Inc., service information identified in this
final rule, 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.
For Parker-Hannifin Corporation service information identified in
this final rule, contact Parker Aerospace, 14300 Alton Parkway, Irvine,
CA 92618; telephone 949-833-3000; fax 949-809-8646; Internet http://
www.parker.com. You may view this referenced service information at the FAA,
Transport Standards Branch, 1601 Lind Avenue SW., Renton, WA. For
information on the availability of this material at the FAA, call 425-
227-1221. It is also available on the Internet at http://www.regulations.gov
by searching for and locating Docket No. FAA-2015-8434.

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-2015-
8434; 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 AD, the regulatory evaluation, any comments received, and
other information. The street address for the Docket Office (telephone
800-647-5527) is Docket Management Facility, 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: 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:

Discussion

We issued a supplemental notice of proposed rulemaking (SNPRM) to
amend 14 CFR part 39 by adding an AD that would apply to certain
Bombardier, Inc., Model DHC-8-401 and -402 airplanes. The SNPRM
published in the Federal Register on July 14, 2017 (82 FR 32496) (``the
SNPRM''). We preceded the SNPRM with a notice of proposed rulemaking
(NPRM) that published in the Federal Register on January 13, 2016 (81
FR 1586) (``the NPRM''). The NPRM proposed to require replacement of
affected spoiler PCUs. The NPRM was prompted by the discovery of
cracking on two test spoiler PCU manifolds during testing by the
manufacturer. The SNPRM proposed to require replacement of affected
spoiler PCUs, and also proposed to add airplanes to the applicability.
We are issuing this AD to prevent cracking of the spoiler PCUs that
could lead to the loss of multiple flight controls and landing gear
systems.
Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian Airworthiness Directive CF-
2015-07R2, dated December 14, 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-8-401 and -402
airplanes. The MCAI states:

During endurance and impulse testing of the spoiler PCU, cracks
were discovered on two test spoiler PCU manifolds. Investigation
determined that the crack initiation was due to the heat treat
process. A cracked spoiler PCU manifold could cause the loss of one
of the two hydraulic systems, resulting in the loss of multiple
flight controls and landing gear systems. This condition, if not
corrected, could adversely affect the continued safe operation and
landing of the aeroplane.
This [Canadian] AD mandates the replacement of the affected
spoiler PCUs.
Revision 1 of this [Canadian] AD was issued to extend the
applicability to include additional aeroplane serial numbers and
also modify the Corrective Actions to specifically mandate section
3.B of the [Bombardier Service Bulletin] SB 84-27-64, Revision A.
Revision 2 of this [Canadian] AD was issued to correct the SB
referenced in the Background section. SB 84-27-64, Revision A should
have been referenced in lieu of SB 84-27-63, Revision A.

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-2015-
8434.

Comments

We gave the public the opportunity to participate in developing
this AD. We received no comments on the SNPRM or on the determination
of the cost to the public.

Conclusion

We reviewed the relevant data and determined that air safety and
the public interest require adopting this AD as proposed except for
minor editorial changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the
SNPRM for correcting the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the SNPRM.

Related Service Information Under 1 CFR Part 51

Bombardier, Inc., has issued Service Bulletin 84-27-64, Revision A,
dated July 26, 2016. This service information describes procedures for
replacement of affected spoiler PCU manifolds.
Parker-Hannifin Corporation has issued Service Bulletin 390700-27-
002, Revision 1, dated April 13, 2016. This service bulletin identifies
affected spoiler PCUs.
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 82 airplanes of U.S. registry.
We estimate the following costs to comply with this 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.
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 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):