DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0638; Product Identifier 2018-NM-016-AD]
RIN 2120-AA64

Airworthiness Directives; Viking Air Limited (Type Certificate
Previously Held by Bombardier, Inc.; Canadair Limited) Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede Airworthiness Directive (AD) 2013-11-
03, which applies to certain Viking Air Limited Model CL-215-1A10 and
CL-215-6B11 (CL-215T Variant) airplanes. AD 2013-11-03 requires
repetitive detailed inspections for cracking of the left-hand (LH) and
right-hand (RH) wing lower skin, and repair if necessary. AD 2013-11-03
was prompted by reports of a fractured wing lower rear spar cap and
reinforcing strap. Since we issued AD 2013-11-03, further analysis has
indicated the need for repetitive eddy current and borescope
inspections. This proposed AD would require repetitive borescope
inspections of the LH and RH wing lower skin and repetitive eddy
current inspections of the LH and RH wing front and rear lower spar
caps. We are proposing this AD to address the unsafe condition on these
products.

DATES: We must receive comments on this proposed AD by September 17, 2018.

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 Viking Air
Limited, 1959 de Havilland Way, Sidney, British Columbia V8L 5V5,
Canada; telephone +1-250-656-7227; fax +1-250-656-0673; email acs-
technical.publications@vikingair.com; internet http://www.vikingair.com.
You may view this referenced 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-2018-
0638; 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 NPRM, 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: 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-2018-0638;
Product Identifier 2018-NM-016-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

We issued AD 2013-11-03, Amendment 39-17463 (78 FR 32353, May 30,
2013) ("AD 2013-11-03"), for certain Viking Air Limited Model CL-215-
1A10 and CL-215-6B11 (CL-215T Variant) airplanes. AD 2013-11-03
requires repetitive detailed inspections for cracking of the LH and RH
wing lower skin, and repair if necessary. AD 2013-11-03 resulted from
reports of a fractured wing lower rear spar cap and reinforcing strap.
We issued AD 2013-11-03 to detect and correct cracked wing structure,
which could result in failure of the wing.

Actions Since AD 2013-11-03 Was Issued

Since we issued AD 2013-11-03, an operator reported damage to the
wing lower skin and rear spar of an airplane. This damage was noticed
95 flight hours after an ultrasonic inspection. Further analysis by the
airplane manufacturer and the FAA has determined that the ultrasonic
inspection might not have been adequate to detect a crack in the spar
cap, and there is a need for repetitive eddy current and borescope
inspections.

Transport Canada Civil Aviation (TCCA), which is the aviation
authority for Canada, has issued Canadian Airworthiness Directive, CF-
2013-11R1, dated October 30, 2017 (referred to after this as the
Mandatory Continuing Airworthiness Information, or "the MCAI"), to
correct an unsafe condition for certain Viking Air Limited Model CL-
215-1A10 and CL-215-6B11 (CL-215T Variant) airplanes. The MCAI states:

While performing modifications on a CL-215-1A10 aeroplane, an
operator discovered that the wing lower rear spar cap and
reinforcing strap were fractured at Wing Stations (WS) 49.5 and 50
respectively and the rear spar web and wing lower skin were also
cracked. It is suspected that a crack initiated at the wing lower
spar cap, leading to its failure, the subsequent failure of the
reinforcing strap and cracking of the spar web and wing lower skin.
The damage was outside of the area addressed by the repetitive
ultrasonic inspections required by [Canadian] AD CF-1992-26R2 [which
corresponds to FAA AD 2012-11-04, Amendment 39-17067 (77 FR 32892,
June 4, 2012)] and was found 95 hours air time after the last
ultrasonic inspection.

Failure and cracking of the above-noted wing structure, if not
detected, could result in failure of the wing.

In order to mitigate the unsafe condition, [Canadian] AD CF-
2013-11 [which corresponds to FAA AD 2013-11-03] was released.
However, further analysis has indicated the need for repetitive eddy
current and borescope inspections. Therefore, Revision 1 of this
[Canadian] AD mandates a repetitive detailed inspection of the wing
lower skin using a borescope, changes the one-time eddy current
inspection of the lower front and rear spar caps to a repetitive
inspection and eliminates the one-time detailed inspection with fuel
bladders removed.

The requirements of [Canadian] AD CF-1992-26R2 remain applicable.

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-2018
-0638.

Related Service Information Under 1 CFR Part 51

Bombardier has issued Alert Service Bulletin 215-A558, Revision 3,
dated June 3, 2016. This service information describes procedures for
detecting cracks using repetitive borescope inspections of the LH and
RH wing lower skin and repetitive eddy current inspections of the LH
and RH wing front and rear lower spar caps. 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 these
same type designs.

Costs of Compliance

We estimate that this proposed AD affects 4 airplanes of U.S.
registry. We estimate the following costs to comply with this proposed
AD:

Estimated Costs

We have received no definitive data that would enable us to provide
cost estimates for the on-condition actions specified in this proposed
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.

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 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 removing Airworthiness Directive (AD)
2013-11-03, Amendment 39-17463 (78 FR 32353, May 30, 2013), and adding
the following new AD: