DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-0684; Directorate Identifier 2014-NM-215-AD;
Amendment 39-18285; AD 2015-20-06]
RIN 2120-AA64

Airworthiness Directives; Viking Air Limited (Type Certificate
Previously Held by 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 all
Viking Air Limited (Type Certificate Previously Held by Bombardier,
Inc.) Model DHC-7-1 and DHC-7-100 airplanes. This AD was prompted by
reports of cracks that were discovered in the outboard nacelles upper
longeron channels and angles. This AD requires a one-time detailed
visual inspection for cracking in the outboard nacelles upper longeron
channels and angles; and repair if necessary. We are issuing this AD to
detect and correct cracks in the outboard nacelles upper longeron
channels and angles, which could lead to the loss of stiffness in the
forward engine mount; and possible catastrophic failure.

DATES: This AD becomes effective November 10, 2015.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of November 10,
2015.

ADDRESSES: You may examine the AD docket on the Internet at http://www.regulations.gov/#!docketDetail;D=FAA-2015-0684 or in person at the
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.
For service information identified in this AD, contact Viking Air
Limited, 9574 Hampden Road, Sidney, British Columbia V8L 8V5, Canada;
telephone 250-656-7227; fax 250-656-0673; email
technical.publications@vikingair.com; Internet http://www.vikingair.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. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2015-
0684.

FOR FURTHER INFORMATION CONTACT: Aziz Ahmed, Aerospace Engineer,
Airframe and Mechanical Systems Branch, ANE-171, FAA, New York Aircraft
Certification Office, 1600 Stewart Avenue, Suite 410, Westbury, NY
11590; telephone 516-228 7329; fax 516-794 5531.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 by adding an AD that would apply to all Viking Air Limited
(Type Certificate Previously Held by Bombardier, Inc.) Model DHC-7-1
and DHC-7-100 airplanes. The NPRM published in the Federal Register on
April 13, 2015 (80 FR 19572).
Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian Airworthiness Directive CF-
2014-34, dated October 2, 2014, dated (referred to after this as the
Mandatory Continuing Airworthiness Information, or ``the MCAI''), to
correct an unsafe condition for all Viking Air Limited (Type
Certificate Previously Held by Bombardier, Inc.) Model DHC-7-1 and DHC-
7-100 airplanes. The MCAI states:

Longitudinal cracks were discovered in the outboard nacelles
upper longeron channels and angles at station XN1 78. The cracks
were partially hidden by bearing blocks, Part Number (P/N) 75420978,
at the nacelle latch locations. Undetected, these cracks may lead to
the loss of stiffness in the forward engine mount; which may lead to
a catastrophic failure.

Required actions include a one-time detailed visual inspection for
cracking of the outboard nacelles upper longeron channels and angles.
Corrective actions include repair, if necessary. You may examine the
MCAI in the AD docket on the Internet at http://www.regulations.gov/#!documentDetail;D=FAA-2015-0684-0002.

Comments

We gave the public the opportunity to participate in developing
this AD. We received no comments on the NPRM (80 FR 19572, April 13,
2015) 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
NPRM (80 FR 19572, April 13, 2015) for correcting the unsafe condition;
and
Do not add any additional burden upon the public than was
already proposed in the NPRM (80 FR 19572, April 13, 2015).

Related Service Information Under 1 CFR Part 51

Viking Air Limited has issued Service Bulletin V7-54-02, Revision
NC, dated December 14, 2012. The service information describes
procedures for an inspection for cracks in the outboard nacelles upper
longeron channels and angles; and repair if necessary. 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 of this AD.

Costs of Compliance

We estimate that this AD affects 10 airplanes of U.S. registry.
We also estimate that it will take about 3 work-hours per product
to comply with the basic requirements of this AD. The average labor
rate is $85 per work-hour. Based on these figures, we estimate the cost
of this AD on U.S. operators to be $2,550, or $255 per product.
We have received no definitive data that would enable us to provide
cost estimates for the on-condition actions specified in this 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.

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.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov/#!docketDetail;D=FAA-2015-0684; 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 Operations office (telephone 800-647-
5527) is in the ADDRESSES section.

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):