DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0045; Product Identifier 2018-CE-027-AD; Amendment
39-21199; AD 2020-16-15]
RIN 2120-AA64

Airworthiness Directives; Viking Air Limited Airplanes

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

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Viking Air Limited Models DHC-2 Mk. I and DHC-2 Mk. III
airplanes. This AD results from mandatory continuing airworthiness
information (MCAI) issued 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 cracks reported on the forward
and aft float strut wire pull fittings. The FAA is issuing this AD to
address the unsafe condition on these products.

DATES: This AD is effective September 21, 2020.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in the AD as of September 21,
2020.

ADDRESSES: You may examine the AD docket on the internet at https://www.
regulations.gov by searching for and locating Docket No. FAA-2019-
0045; or in person at Docket Operations, 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 service information identified in 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:
https://www.vikingair.com/support/service-bulletins. You may view this
referenced service information at the FAA, Airworthiness Products
Section, Operational Safety Branch, 901 Locust, Kansas City, Missouri
64106. For information on the availability of this material at the FAA,
call (816) 329-4148. It is also available on the internet at https://www.
regulations.gov by searching for Docket No. FAA-2019-0045.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.gov
by searching for and locating Docket No. FAA-2019-
0045; or in person at Docket Operations between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays. The AD docket contains
the notice of proposed rulemaking (NPRM), the regulatory evaluation,
any comments received, and other information. The street address for
Docket Operations is listed above. 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:

Discussion

The FAA issued an NPRM to amend 14 CFR part 39 by adding an AD that
would apply to Viking Air Limited Models DHC-2 Mk. I and DHC-2 Mk. III
airplanes. The NPRM published in the Federal Register on February 11,
2019 (84 FR 3131). The NPRM proposed to correct an unsafe condition for
the specified products and was based on AD Number CF-2018-10, dated
April 18, 2018 (referred to after this as ``the MCAI''), issued by
Transport Canada, which is the aviation authority for Canada. The MCAI
states:

Cracks have been reported on the Forward and Aft float strut
wire pull fittings on DHC-2 Mk. I aeroplanes equipped with the 5600
lb gross weight increase kit installed in accordance with STC SA92-
63 or SA00299NY and on DHC-2 Mk. III aeroplanes equipped with the
6000 lb gross weight increase kit installed in accordance with STC
SA91-18 or SA945NE. An investigation found that the forward and aft
wire pull fittings (P/N VALTBS1245-1/-2 and P/N VALTBS1244-1,
respectively) are prone to stress corrosion cracking at low cycles/
hours.
Failure of these wire pull fittings will reduce the strength of
the float undercarriage below the required structural capability and
could result in a failure of the undercarriage causing the aeroplane
to tip over and be submerged.
Therefore this [Transport Canada] AD requires that the forward
and aft wire pull fittings be replaced with P/N VALTBS1245-3/-4 and
P/N VALTBS1244-3/-4 (LH/RH) fittings respectively. These fittings
are geometrically similar to the legacy fittings and are made of a
different aluminum alloy that is less susceptible to stress
corrosion cracking.
In addition to replacing the fittings, it is necessary to
implement a recurring visual inspection of the fittings to assure
continuing airworthiness.

The MCAI can be found in the AD docket on the internet at: https://www.regulations.gov/docket?D=FAA-2019-0045.

Comments

The FAA gave the public the opportunity to participate in
developing this AD. The following presents the comment received on the
NPRM and the FAA's response.

Request To Remove the Repetitive Inspection

Christopher Campbell requested the FAA remove the 110-hour
repetitive inspection requirement. The commenter stated the unsafe
condition is eliminated by the requirement to
replace the affected part. Also, the commenter reasoned that because
repetitive inspections are already required at each 100-hour and annual
inspection by Appendix D to Part 43, Advisory Circular (AC) 43.13, AC
20-106, the manufacturer's maintenance manual, and the float
manufacturer's inspection requirements, the repetitive inspections in
the NPRM are unnecessary and burdensome. The commenter stated that if
the replacement wire pulls are not strong enough to last 110 hours
without cracking, then the FAA should address this at the manufacturing
level and not in the field.
The FAA does not agree. Although 14 CFR 43.15 and Appendix D to
Part 43 do require that 100-hour and annual inspections include an
inspection of floats for insecure attachment and obvious defects, this
AD requires a specific inspection of the wire pull fittings. Also,
while an operator may incorporate into its maintenance program the
inspections in the advisory circulars and manufacturer maintenance
manuals referenced by the commenter, not all operators are required to
do so. In order for these inspections to become mandatory, and to
correct the unsafe conditions identified in the NPRM, the FAA must
issue an AD. The compliance times as proposed should allow the
inspections to be conducted concurrently with scheduled maintenance,
thereby minimizing the costs on operators.
The FAA did not change this AD based on this comment.

Changes to the Final Rule

The FAA has revised the applicability of this AD to include
airplanes with fitting part number VALTBS1244-3 or VALTBS1244-4, to
clarify that replacing the fittings is not terminating action for the
repetitive inspections in the AD. The FAA also made some minor
editorial changes.

Conclusion

The FAA reviewed the relevant data, considered the comment
received, and determined that air safety and the public interest
require adopting the AD with the changes described previously. The FAA
has determined that these minor changes:
Are consistent with the proposal in the NPRM for
correcting the unsafe condition; and
Do not increase any burden upon the public than was
already proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Viking DHC-2 Beaver Service Bulletin No. V2/003,
Revision NC, dated November 28, 2012, for Model DCH-2 Mk. I airplanes;
and Viking DHC-2T Beaver Service Bulletin No. V2/002, Revision A, dated
September 12, 2011, for Model DCH-2 Mk. III airplanes. This service
information contains procedures for replacing the forward and aft float
strut wire pull fittings and specifies implementing repetitive visual
inspections of the fittings. 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.

Differences Between This AD and the MCAI

The MCAI requires returning cracked fittings to Viking, and this AD
does not. The MCAI also prohibits installing an affected wire pull
fitting on any airplane, and this AD does not.

Costs of Compliance

The FAA estimates that this AD will affect 136 products of U.S.
registry. The FAA also estimates that replacing the fittings will take
about 12 work-hours at an average labor rate of $85 per work-hour and
required parts will cost about $2,741. Based on these figures, the FAA
estimates a cost of $3,761 per airplane and $511,496 for the U.S.
operator fleet.
Inspecting the fittings will take about .5 work-hour for an
estimated cost of $42.50 per airplane and $5,780 for the U.S. fleet,
per inspection cycle.

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.
The FAA is 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

The FAA 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 this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Will not affect intrastate aviation in Alaska, and
(3) 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: