[Federal Register Volume 87, Number 105 (Wednesday, June 1, 2022)]
[Rules and Regulations]
[Pages 32975-32978]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-11559]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1003; Project Identifier MCAI-2020-00962-A; 
Amendment 39-22059; AD 2022-11-09]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Viking Air Limited (Viking) (type certificate previously held by 
Bombardier Inc. and de Havilland, Inc.) Model DHC-6-1, DHC-6-100, DHC-
6-200, DHC-6-300, and DHC-6-400 airplanes. This 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 identifies the unsafe 
condition as cracks and corrosion damage to the aileron internal 
structure. This AD requires visually inspecting the entire aileron 
internal structure, correcting any damage found, and reporting the 
inspection results to Viking. The FAA is issuing this AD to address the 
unsafe condition on these products.

DATES: This AD is effective July 6, 2022.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of July 6, 
2022.

ADDRESSES: For service information identified in this final rule, 
contact Viking Air Ltd., 1959 de Havilland Way, Sidney British 
Columbia, Canada V8L 5V5; phone: (800) 663-8444; email: 
[email protected]; website: https://www.vikingair.com. You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 901 Locust, 
Kansas City, MO 64106. For information on the availability of this 
material at the FAA, call (817) 222-5110. It is also available at 
https://www.regulations.gov by searching for and locating Docket No. 
FAA-2020-1003.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2020-1003; or in person at 
Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The AD docket contains this final rule, the 
MCAI, any comments received, and other information. The address for 
Docket Operations is 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: Deep Gaurav, Aviation Safety Engineer, 
New York ACO Branch, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 
11590; phone: (516) 228-7300; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to all Viking Model DHC-6-
1, DHC-6-100, DHC-6-200, DHC-6-300, and DHC-6-400 airplanes. The NPRM 
published in the Federal Register on January 21, 2022 (87 FR 3236). The 
NPRM was prompted by MCAI from Transport Canada, which is the aviation 
authority for Canada. Transport Canada issued AD CF-2020-05, dated 
March 13, 2020 (referred to after this as ``the MCAI''), to correct an 
unsafe condition on Viking Model DHC-6 series 1, DHC-6 series 100, DHC-
6 series 110, DHC-6 series 200, DHC-6 series 210, DHC-6 series 300, 
DHC-6 series 310, DHC-6 series 320, and DHC-6 series 400 airplanes. The 
MCAI states:

    Viking Air Ltd. (Viking) received reports of cracks and 
corrosion damage to the aileron internal structure. During a repair 
of an in-service aeroplane, an aileron hinge support rib was found 
cracked at the lower flange along the bend radius near the hinge 
fitting attachment at wing station 247.29. Preliminary investigation 
by Viking determined that the observed crack was the result of 
fatigue. During an inspection of another in-service aeroplane, the 
aileron inboard rib and the vertical flange of the inboard aileron 
forward spar near a fastener hole were also found cracked.
    The current inspection requirements of the affected aeroplanes 
do not include a direct inspection of the aileron internal 
structure. Cracks or other damage to the aileron ribs or to the 
aileron spar flanges are not detectable from the aileron exterior 
surfaces. Undetected cracks or other damage to the aileron internal 
structure could lead to progressive looseness of the aileron at the 
hinge support rib push-pull rod attachment and subsequent flutter 
condition and degraded or loss of aileron control.
    To detect and correct any cracking or other damage to the 
aileron internal structure, this [Transport Canada] AD mandates a 
one-time Special Detailed Inspection (SDI) of all aileron internal 
structure, including front and rear spars, all aileron ribs and 
upper and lower skins for cracks, corrosion or other damage, and 
rectification, as required, of the damaged parts.
    This [Transport Canada] AD also mandates reporting of all 
inspection results to Viking. The reporting of the inspection 
results is necessary to assess the overall aileron internal 
structural condition on in-service aeroplanes and to determine 
additional corrective action based on the results of the 
inspections.
    Viking has published Service Bulletin (SB) V6/0066 Revision A, 
dated 9 December 2019, (referred to as ``the SB'' in this [Transport 
Canada] AD) providing accomplishment instructions for the 
inspection, rectification of the damaged parts, and reporting 
requirements.

    You may examine the MCAI in the AD docket at https://

[[Page 32976]]

www.regulations.gov by searching for and locating Docket No. FAA-2020-
1003.
    In the NPRM, the FAA proposed to require visually inspecting the 
entire aileron internal structure, correcting any damage found, and 
reporting the inspection results to Viking. The FAA is issuing this AD 
to prevent progressive looseness of the aileron at the hinge support 
rib push-pull rod attachment, flutter condition, and degraded or loss 
of aileron control, which could lead to loss of control of the 
airplane.

Ex Parte Contact

    After the comment period closed, the FAA requested additional 
information from Transport Canada and Viking about the factory drilled 
drain holes in the ailerons. A summary of this discussion can be found 
in the rulemaking docket at https://www.regulations.gov in Docket No. 
FAA-2020-1003.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from one commenter, Mile-Hi Skydiving 
Center (Mile-Hi). The following presents the comment received on the 
NPRM and the FAA's response.

Request Regarding Related Service Information

    Mile-Hi requested that Viking revise DHC-6 Twin Otter Service 
Bulletin V6/0066, Revision A, dated December 9, 2019 (Viking SB V6/
0066, Revision A), to provide instructions for enlarging the aileron 
drain holes. Mile-Hi stated that the existing factory-drilled aileron 
drain holes are \3/16\ inch (0.1875 inch) in diameter and are too small 
to accommodate the borescope used at its facility, which has a diameter 
of \1/4\ inch (0.232 inch). Mile-Hi concluded that the existing aileron 
drain holes will need to be enlarged to accommodate any borescope for 
the proposed inspection. Mile-Hi also requested follow-on actions such 
as reducing the enlarged holes to the original size to prevent ingress 
of nesting insects such as wasps or hornets and static balancing the 
ailerons. As, in the NPRM, the FAA proposed to require inspecting the 
aileron in accordance with steps in Viking SB V6/0066, Revision A, the 
FAA infers that Mile-Hi is requesting that the FAA revise the proposed 
AD to include these actions.
    The FAA does not agree that this AD needs to mandate enlarging the 
aileron drain holes. The FAA contacted Transport Canada and Viking to 
obtain information on whether any other Model DHC-6 airplane operators 
have had similar issues regarding the diameter of the existing aileron 
drain holes. Viking advised that it has received approximately 170 
service bulletin reply forms in response to Viking SB V6/0066, Revision 
A, and operators have successfully done the borescope inspection with 
no difficulty. In addition, Viking confirmed that the 0.1875-inch 
diameter aileron drain hole size is standard per the Model DHC-6 
airplane type design, and that commercially available borescope heads 
fit into the standard-sized holes (as specified in the equipment list 
in Section II.A.1 of Viking SB V6/0066, Revision A). Based on this 
information, the FAA has determined that the borescope diameter is not 
a fleet-wide issue that needs further attention.
    The FAA acknowledges field repairs to replace the aileron skins 
could have been completed on some airplanes where, during replacement, 
the drain holes were omitted or manufactured undersized. If field 
repairs have been done that prevent compliance with the inspection in 
this AD, then the operator will need approval of an alternative method 
of compliance. The FAA did not change this AD based on this comment.

Conclusion

    These products have been approved by the aviation authority of 
another country and are approved for operation in the United States. 
Pursuant to the FAA's bilateral agreement with this State of Design 
Authority, it has notified the FAA of the unsafe condition described in 
the MCAI referenced above. The FAA reviewed the relevant data, 
considered the comment received, and determined that air safety 
requires adopting the AD as proposed. Accordingly, the FAA is issuing 
this AD to address the unsafe condition on these products. This AD is 
adopted as proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Viking DHC-6 Twin Otter Service Bulletin V6/0066, 
Revision A, dated December 9, 2019. The service information specifies 
procedures for visually inspecting the entire aileron internal 
structure, including front and rear spars, all aileron ribs, and upper 
and lower skins; repairing or replacing any damaged part; and reporting 
inspection results to Viking Air Limited technical support. 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.

Other Related Service Information

    The FAA also reviewed Viking DHC-6 Twin Otter Service Bulletin V6/
0066, Revision NC, dated August 29, 2019. The service information 
specifies procedures for visually inspecting the aileron ribs, 
including ribs and both sides of the hinge arm; repairing or replacing 
any damaged part; and reporting inspection results to Viking Air 
Limited technical support.

Interim Action

    The FAA considers that this AD is an interim action. The inspection 
reports will provide the FAA and Viking additional data for determining 
the damage present in the fleet. After analyzing the data, the FAA may 
take further rulemaking action.

Differences Between This AD and the MCAI

    The MCAI applies to Viking Air Limited Model DHC-6 series 110, DHC-
6 series 210, DHC-6 series 310, and DHC-6 series 320, and this AD does 
not because these models do not have an FAA type certificate. Model 
DHC-6 series 1, DHC-6 series 100, DHC-6 series 200, DHC-6 series 300, 
and DHC-6 series 400 airplanes specified in the MCAI correspond to FAA 
Model DHC-6-1, DHC-6-100, DHC-6-200, DHC-6-300, and DHC-6-400 
airplanes, respectively.

Costs of Compliance

    The FAA estimates that this AD affects 33 airplanes of U.S. 
registry. The FAA also estimates that it would take about 3 work-hours 
per airplane to comply with the inspection and 1 work-hour to comply 
with the reporting requirement of this AD. The average labor rate is 
$85 per work-hour.
    Based on these figures, the FAA estimates the cost of this AD on 
U.S. operators will be $11,220 or $340 per airplane.
    In addition, the FAA estimates that any necessary follow-on actions 
to replace an aileron would take 6 work-hours and require parts costing 
$52,243, for a cost of $52,753 per airplane. The FAA has no way of 
determining the number of airplanes that may need these actions.

Paperwork Reduction Act

    A federal agency may not conduct or sponsor, and a person is not 
required to respond to, nor shall a person be subject to a penalty for 
failure to comply with a collection of information subject to the 
requirements of the Paperwork Reduction Act unless that collection of 
information displays a currently valid OMB Control Number. The OMB

[[Page 32977]]

Control Number for this information collection is 2120-0056. Public 
reporting for this collection of information is estimated to take 
approximately 1 hour per response, including the time for reviewing 
instructions, searching existing data sources, gathering and 
maintaining the data needed, and completing and reviewing the 
collection of information. All responses to this collection of 
information are mandatory. Send comments regarding this burden estimate 
or any other aspect of this collection of information, including 
suggestions for reducing this burden to: Information Collection 
Clearance Officer, Federal Aviation Administration, 10101 Hillwood 
Parkway, Fort Worth, TX 76177-1524.

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

    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) 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.

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

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2022-11-09 Viking Air Limited (Type Certificate Previously Held by 
Bombardier Inc. and de Havilland, Inc.): Amendment 39-22059; Docket 
No. FAA-2020-1003; Project Identifier MCAI-2020-00962-A.

(a) Effective Date

    This airworthiness directive (AD) is effective July 6, 2022.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Viking Air Limited (type certificate 
previously held by Bombardier Inc. and de Havilland, Inc.) Model 
DHC-6-1, DHC-6-100, DHC-6-200, DHC-6-300, and DHC-6-400 airplanes, 
all serial numbers, certificated in any category.

(d) Subject

    Joint Aircraft System Component (JASC) Code 5700, Wing 
Structure.

(e) Unsafe Condition

    This AD was prompted by 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 identifies the unsafe condition as cracks and 
corrosion damage to the aileron internal structure. The FAA is 
issuing this AD to detect and correct cracks and other damage to the 
aileron internal structure. The unsafe condition, if not addressed, 
could result in progressive looseness of the aileron at the hinge 
support rib push-pull rod attachment, flutter condition, and 
degraded or loss of aileron control, which could lead to loss of 
control of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Inspection and Replacement of the Aileron

    At the compliance time specified in paragraph (g)(1) or (2) of 
this AD, inspect the left-hand (LH) and right-hand (RH) aileron 
internal structures for cracks, corrosion, and other damage and take 
any necessary corrective actions in accordance with the 
Accomplishment Instructions, steps II.A. through II.A.3. of Viking 
DHC-6 Twin Otter Service Bulletin V6/0066, Revision A, dated 
December 9, 2019 (Viking SB V6/0066, Revision A).
    (1) For each LH or RH aileron that has accumulated 16,000 or 
more hours time-in-service (TIS), 32,000 or more flight cycles (FC), 
or 10 or more years since first installation on an airplane, 
whichever occurs first: Within 6 months after the effective date of 
this AD.
    (2) For each LH or RH aileron that has accumulated less than 
16,000 hours TIS, less than 32,000 FC, and less than 10 years since 
first installation on an airplane: Within 6 months after 
accumulating 16,000 hours TIS, 32,000 FC, or 10 years, whichever 
occurs first.

(h) Reporting Requirement

    Within 30 days after the inspection required by paragraph (g)(1) 
or (2) of this AD or within 30 days after the effective date of this 
AD, whichever occurs later, report to Viking the information 
requested on the Inspection Reply Form, page 7, of Viking SB V6/
0066, Revision A.

(i) Credit for Previous Actions

    You may take credit for the actions required by paragraphs 
(g)(1) and (2) of this AD if you performed those actions before the 
effective date of this AD using Viking DHC-6 Twin Otter Service 
Bulletin V6/0066, Revision NC, dated August 29, 2019.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, New York ACO Branch, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or local Flight Standards District 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in paragraph (k)(1) of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(k) Related Information

    (1) For more information about this AD, contact Deep Gaurav, 
Aviation Safety Engineer, New York ACO Branch, FAA, 1600 Stewart 
Avenue, Suite 410, Westbury, NY 11590; phone: (516) 228-7300; email: 
[email protected].
    (2) Refer to Transport Canada AD CF-2020-05, dated March 13, 
2020, for more information. You may examine the Transport Canada AD 
at https://www.regulations.gov by searching for and locating Docket 
No. FAA-2020-1003.

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference

[[Page 32978]]

(IBR) of the service information listed in this paragraph under 5 
U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Viking DHC-6 Twin Otter Service Bulletin V6/0066, Revision 
A, dated December 9, 2019.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact 
Viking Air Ltd., 1959 de Havilland Way, Sidney, British Columbia, 
Canada V8L 5V5; phone: (800) 663-8444; email: 
[email protected]; website: https://www.vikingair.com.
    (4) You may view this service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 901 
Locust, Kansas City, MO 64106. For information on the availability 
of this material at the FAA, call (817) 222-5110.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on May 17, 2022.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2022-11559 Filed 5-31-22; 8:45 am]
BILLING CODE 4910-13-P


