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PROPOSED AD VIKING AIR LIMITED: Docket No. FAA-2018-0189; Product Identifier 2017-CE-022-AD.
(a) COMMENTS DUE DATE

    We must receive comments by April 27, 2018.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This AD applies to Viking Air Limited Model DHC-3 airplanes  with wing
    strut bolts wing strut bolts part numbers (P/N) C3W114-3, C3W129-3 and
    C3W128-3 (Pre MOD 3/1010),  all  serial  numbers,  certificated in any
    category.

(d) SUBJECT

    Air Transport Association of America (ATA) Code 57: Wings.

(e) REASON

    This AD was prompted by from mandatory continuing airworthiness infor-
    mation (MCAI) originated by  an aviation authority of  another country
    to identify and  correct an unsafe  condition on an  aviation product.
    The MCAI describes  the unsafe condition  as pitting corrosion  on the
    shank of the wing strut attach bolts. We are issuing this proposed  AD
    to detect and correct pitting and un-plated voids, which could cause a
    surface condition that  may have a  detrimental effect on  fatigue and
    corrosion resistance, leading to  bolt failure and subsequent  failure
    of the wing.

(f) ACTIONS AND COMPLIANCE

    Unless already done, do the following actions:

(1) Within the next 12 months after the effective date of this AD, inspect
    the wing strut attach bolts installed  on the airplane  for pitting on
    the shank following  paragraph A of the Accomplishment Instructions of
    Viking DHC-3 Otter Service Bulletin (SB) Number: V3/0006,  Revision B,
    dated March 9, 2017.

(2) If pitting is found  after the inspection required in paragraph (f)(1)
    of this AD, before further flight, replace the bolt with either a post
    MOD 3/1010 wing strut bolt  (Part Numbers (P/Ns) C3W114-5, C3W129-5 or
    C3W128-5 as applicable)  or  a  new or serviceable pre MOD 3/1010 wing
    strut bolt  that  has been  inspected  following paragraph A of Viking
    DHC-3 Otter SB Number: V3/0006, Revision B, dated March 9, 2017.

(3) After the effective date of this AD, pre MOD 3/1010 bolts may continue
    to be used provided these bolts are inspected  for pitting immediately
    before  installation  following  paragraph  A  of  the  Accomplishment
    Instructions  of  Viking DHC-3 Otter SB Number:  V3/0006,  Revision B,
    dated March 9, 2017,  and the accomplishment of the inspection must be
    documented in the airplane maintenance records.

(g) CREDIT FOR ACTIONS ACCOMPLISHED  IN  ACCORDANCE  WITH PREVIOUS SERVICE
    INFORMATION

    This AD allows credit  for the actions required in paragraph (f)(1) or
    (2) of this AD  if done before the effective date of this AD following
    SB Viking DHC-3 Otter V3/0006 Revision NC or A.

(h) OTHER FAA AD PROVISIONS

    The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs):  The Manager,  New York ACO
    Branch,  FAA,  has the authority to approve AMOCs for this AD,  if re-
    quested using the procedures found in 14 CFR 39.19.  Send  information
    to  ATTN: Aziz Ahmed,  Aerospace Engineer,  FAA,  New York ACO Branch,
    1600 Stewart Avenue,  Suite 410, Westbury, New York 11590;  telephone:
    (516) 287-7329; fax: (516) 794-5531; email: aziz.ahmed@faa.gov. Before
    using any approved AMOC  on  any  airplane  to which the AMOC applies,
    notify your appropriate principal inspector  (PI)  in  the  FAA Flight
    Standards District Office (FSDO), or lacking a PI, your local FSDO.

(2) Contacting the Manufacturer:  For any requirement in this AD to obtain
    corrective  actions   from  a   manufacturer,  the   action  must   be
    accomplished using  a method  approved by  the Manager,  New York  ACO
    Branch, FAA; or  Transport Canada; or  Viking Air Limited's  Transport
    Canada Design Organization Approval (DOA). If approved by the DOA, the
    approval must include the DOA-authorized signature.

(i) RELATED INFORMATION

    Refer to  MCAI Transport Canada AD Number CF-2017-11,  dated  March 9,
    2017, for related information.  You may examine the MCAI on the inter-
    net at http://www.regulations.gov by searching for and locating Docket
    No. FAA-2018-0189. For service information related to this AD, contact
    Viking Air Limited Technical Support,  1959 De Havilland Way,  Sidney,
    British Columbia, Canada, V8L 5V5;  telephone:  (North America)  (800)
    663-8444; fax: (250) 656-0673; email: technical.support@vikingair.com;
    internet: http://www.vikingair.com/support/service-bulletins.  You may
    review  this referenced service information  at  the  FAA,  Policy and
    Innovation Division, 901 Locust, Kansas City, Missouri 64106.  For in-
    formation on the availability of this material at the FAA,  call (816)
    329-4148.

Issued  in  Kansas City, Missouri,  on March 6, 2018.  Pat Mullen,  Acting
Deputy Director,  Policy  &  Innovation  Division,  Aircraft Certification
Service.

DATES: We must receive comments on this proposed AD by April 27, 2018.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0189; Product Identifier 2017-CE-022-AD]
RIN 2120-AA64

Airworthiness Directives; Viking Air Limited Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: We propose to adopt a new airworthiness directive (AD) for
Viking Air Limited Model DHC-3 airplanes. This proposed AD results from
mandatory continuing airworthiness information (MCAI) originated by an
aviation authority of another country to identify and correct an unsafe
condition on an aviation product. The MCAI describes the unsafe
condition as pitting corrosion on the shank of the wing strut attach
bolts. We are issuing this proposed AD to require actions to address
the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by April 27, 2018.

ADDRESSES: You may send comments 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: U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE,
Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays.

For service information identified in this proposed AD, contact
Viking Air Limited Technical Support, 1959 De Havilland Way, Sidney,
British Columbia, Canada, V8L 5V5; telephone: (North America) (800)
663-8444; fax: (250) 656-0673; email: technical.support@vikingair.com;
internet: http://www.vikingair.com/support/service-bulletins. You may
review this referenced service information at the FAA, Policy and
Innovation Division, 901 Locust, Kansas City, Missouri 64106. For
information on the availability of this material at the FAA, call (816)
329-4148.

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-2018-0189;
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
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, FAA,
New York ACO Branch, 1600 Stewart Avenue, Suite 410, Westbury, New York
11590; telephone: (516) 287-7329; fax: (516) 794-5531; email:
aziz.ahmed@faa.gov.

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-2018-0189;
Product Identifier 2017-CE-022-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 because of those comments.

We will post all comments we receive, without change, to http://
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, which is the aviation authority for Canada, has
issued AD Number CF-2017-11, dated March 9, 2017 (referred to after
this as "the MCAI"), to correct an unsafe condition for Viking Air
Limited Model DHC-3 airplanes and was based on mandatory continuing
airworthiness information originated by an aviation authority of
another country. The MCAI states:

Pitting corrosion has been found on the shank of the following
part number wing strut attach bolts: C3W114-3, C3W129-3 and C3W128-
3. These bolts are manufactured using a standard AN12 bolt.
Metallurgical evaluation concluded that pitting corrosion was
present on the affected AN12 bolts prior to forming of the bolt head
and threads. The pitting and un-plated voids could cause a surface
condition that may have a detrimental effect on fatigue and
corrosion resistance, leading to bolt failure and consequent failure
of the wing.

Viking has not been able to confirm the affected batch numbers
or specific manufacture date range. New wing strut bolts
manufactured after 21 March 2016 are inspected for pitting during
manufacturing and issued new P/Ns C3W114-5, C3W129-5 and C3W128-5
under MOD 3/1010.

You may examine the MCAI on the internet at http://www.regulations.gov by
searching for and locating Docket No. FAA-2018-0189.

Related Service Information Under 1 CFR Part 51


Viking Air Limited has issued DHC-3 Otter Service Bulletin Number
V3/0006, Revision B, dated March 9, 2017. The service information
describes procedures for inspection and any necessary corrective action
for pitting of the wing strut shank bolts. 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 NPRM.

FAA's Determination and Requirements of the 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 this State of Design Authority, they
have notified us of the unsafe condition described in the MCAI and
service information referenced above. We are proposing this AD because
we evaluated all information and determined the unsafe condition exists
and is likely to exist or develop on other products of the same type
design.

Costs of Compliance

We estimate that this proposed AD will affect 37 products of U.S.
registry. We also estimate that it would take about 4 work-hours per
product to comply with the basic requirements of this proposed AD. The
average labor rate is $85 per work-hour.

Based on these figures, we estimate the cost of the proposed AD on
U.S. operators to be $12,580, or $340 per product.

In addition, Table 1 is an estimate of possible necessary follow-on
actions as a result of the required inspections. We have no way of
determining the number of products that may need these actions. We
estimate that any necessary follow-on replacement parts would cost as
follows:

Replacing each affected bolt is on condition and is estimated to
take about 1 work-hour at $85 for a cost of $85 per bolt.

TABLE 1 - PARTS REPLACEMENT AND TOTAL BOLT COST

PART NO. QUANTITY PER WING QUANTITY PER AIRPLANE PRICE PER BOLT ($ USD) TOTAL COST PER BOLT (LABOR AND PARTS)
C3W114-5
2
4
$284
$369
C3W128-5
1
2
275
360
C3W129-5
1
2
164
249

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 small airplanes and domestic
business jet transport airplanes to the Director of the Policy and
Innovation 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 AD: