[Federal Register Volume 86, Number 121 (Monday, June 28, 2021)]
[Proposed Rules]
[Pages 33916-33918]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-13636]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0214; Project Identifier 2018-CE-064-AD]
RIN 2120-AA64


Airworthiness Directives; Viking Aircraft Limited Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all Viking Air Limited Model DHC-3 airplanes. This proposed 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 fatigue damage of the wing strut lug fitting 
components and the fuselage to wing strut attachment (tie-bar). This 
proposed AD would require determining service life limits for the wing 
strut fitting on the main spar and for the tie-bar and following 
instructions for removal and replacement of affected parts. The FAA is 
proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by August 12, 
2021.

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 https://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 Technical Support, 1959 De Havilland Way, Sidney, British 
Columbia, Canada, V8L 5V5; phone: (North America) (800) 663-8444; fax: 
(250) 656-0673; email: [email protected]; website: 
https://www.vikingair.com/support/service-bulletins. 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 (816) 
329-4148.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0214; 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 NPRM, any comments 
received, and other information. The street address for Docket 
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Aziz Ahmed, Aviation Safety Engineer, 
New York ACO Branch, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 
11590; phone: (516) 287-7329; fax: (516) 794-5531; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2021-0214; Project Identifier 
2018-CE-064-AD'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. The FAA 
will consider all comments received by the closing date and may amend 
this proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
https://www.regulations.gov, including any personal information you 
provide. The agency will also post a report summarizing each 
substantive verbal contact received about this NPRM.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this NPRM. Submissions containing CBI should be sent to Aziz 
Ahmed, Aviation Safety Engineer, New York ACO Branch, FAA, 1600 Stewart 
Avenue, Suite 410, Westbury, NY 11590. Any commentary that the FAA 
receives which is not specifically designated as CBI will be placed in 
the public docket for this rulemaking.

Background

    Transport Canada, which is the aviation authority for Canada, has 
issued AD Number CF-2017-29, dated August 24, 2017 (referred to after 
this as ``the MCAI''), to correct an unsafe condition for Viking Air 
Limited Model DHC-3 airplanes. The MCAI states:

    It has been determined that the current maintenance program does 
not adequately address potential fatigue damage of the wing strut 
lug fitting components or the fuselage to wing strut attachment (Tie 
Bar). Affected parts must be replaced before specified air time 
limits are reached to avoid fatigue cracking of the affected parts. 
Cracking which is not detected may compromise the structural 
integrity of the wing or the Tie-Bar.
    Fatigue damage occurs more rapidly on aeroplanes that are 
operated at higher gross weights. For that reason, the corrective 
actions of this [Transport Canada] AD must be accomplished sooner 
for aeroplanes that have been certified for operation at higher 
gross weights.
    Fatigue damage also occurs more rapidly on aeroplanes that are 
operated below 2000 feet above ground level (AGL) over land due to 
higher and more frequent gust and maneuvering loads. Low level 
flights over water are not known to produce increased fatigue damage 
on the DHC-3. For that reason, the corrective actions of this 
[Transport Canada] AD must be accomplished sooner for aeroplanes 
that have been operated at low altitudes over land.

    This condition, if not addressed, could result in cracking and 
failure of the structural integrity of the wing or the tie-bar.
    You may examine the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
0214.

[[Page 33917]]

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Viking Air Limited DHC-3 Otter Service Bulletin 
Number V3/0008, Revision NC, dated February 9, 2017. The service 
information specifies determining service life limits for the wing 
strut fitting on the main spar and for the tie-bar, and contains 
instructions for removal and replacement. De Havilland Aircraft of 
Canada has issued DHC-3 Otter Service Bulletin Number 3/37, Revision B, 
dated October 8, 1982. The service information specifies instructions 
for removal and replacement of the Fuselage to Wing Strut Attachment 
Tie-Bar. 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 ADDRESSES.

FAA's Determination

    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, it has 
notified the FAA of the unsafe condition described in the MCAI and 
service information referenced above. The FAA is issuing this NPRM 
after determining the unsafe condition described previously is likely 
to exist or develop on other products of the same type design.

Proposed AD Requirements in This NPRM

    This AD requires accomplishing the actions specified in the service 
information already described.

Differences Between This Proposed AD and the MCAI

    The MCAI requires calculating the compliance time by using a 
formula and estimating the altitudes at which an airplane has operated. 
The MCAI also instructs operators to assume operations below 2,000 feet 
AGL when the operating altitude of the airplane is unknown. Because the 
FAA has no regulatory requirement for owners or operators to record or 
maintain the operating altitude history of an aircraft, this proposed 
AD would require calculating the compliance time by assuming all 
operations occurred below 2,000 feel AGL.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 41 airplanes of U.S. registry.
    The FAA also estimates that it would take about 300 work-hours per 
airplane to replace both the wing strut fitting and the tie-bar. The 
average labor rate is $85 per work-hour. Required parts would cost 
about $5,599 per airplane.
    Based on these figures, the FAA estimates the cost of the proposed 
AD on U.S. operators to be $1,275,059 or $31,099 per airplane.

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 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) Would not affect intrastate aviation in Alaska, and
    (3) Would 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

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:

Viking Air Limited: Docket No. FAA-2021-0214; Project Identifier 
2018-CE-064-AD.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by August 12, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Viking Air Limited Model DHC-3 airplanes, all 
serial numbers, certificated in any category.

(d) Subject

    Joint Aircraft System Component (JASC) Code 5700, Wings.

(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 describes the unsafe condition as fatigue damage 
of the wing strut lug fitting components or the fuselage to wing 
strut attachment (tie-bar). The FAA is issuing this AD to identify 
and correct potential fatigue damage of the wing strut lug fitting 
components of the fuselage to wing strut attachment. The unsafe 
condition, if not addressed, could result in cracking and failure of 
the structural integrity of the wing or the tie-bar.

(f) Actions and Compliance

    Unless already done, do the following actions in paragraphs 
(f)(1) through (3):
    (1) For all airplanes: Within 3 months after the effective date 
of this AD, determine and record the number of equivalent air time 
hours on each wing and tie-bar by doubling the total hours time-in-
service (TIS) accumulated on each part. If the total hours TIS of a 
tie-bar is unknown or cannot be determined, use the total hours TIS 
of the wing strut lug fitting on the main spar.
    (2) For airplanes with a maximum certificated gross weight that 
has never exceeded 8,000 pounds: Remove from service each left and 
right hand wing strut fitting and tie-bar by following the 
Accomplishment Instructions in Viking Air Limited SB V3/0008, 
Revision NC, dated February 9, 2017, and the Replacement section of 
the Accomplishment instructions in De Havilland Aircraft of Canada 
DHC-3 Otter Service Bulletin Number 3/37, Revision B, dated October 
8, 1982, at whichever of the following compliance time that occurs 
later:

[[Page 33918]]

    (i) Before the part accumulates 40,000 equivalent air time 
hours, or
    (ii) Within 12 months after the effective date of this AD.
    (3) For airplanes with a maximum certificated gross weight that 
has ever exceeded 8,000 pounds: Remove from service each left and 
right hand wing strut fitting and tie-bar by following the 
Accomplishment Instructions in Viking Air Limited SB V3/0008, 
Revision NC, dated February 9, 2017, and the Replacement section of 
the Accomplishment instructions in De Havilland Aircraft of Canada 
DHC-3 Otter Service Bulletin Number 3/37, Revision B, dated October 
8, 1982, at whichever of the following compliance time that occurs 
later:
    (i) Before the part accumulates 32,200 equivalent air time 
hours, or
    (ii) Within 12 months after the effective date of this AD.

(g) 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 ACO Branch, send it to the attention of the person 
identified in paragraph (h)(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.

(h) Related Information

    (1) For more information about this AD, contact Aziz Ahmed, 
Aviation Safety Engineer, New York ACO Branch, FAA, 1600 Stewart 
Avenue, Suite 410, Westbury, NY 11590; phone: (516) 287-7329; fax: 
(516) 794-5531; email: [email protected].
    (2) Refer to Transport Canada AD Number CF-2017-29, dated August 
24, 2017, for more information. You may examine the Transport Canada 
AD in the AD docket at https://www.regulations.gov by searching for 
and locating it in Docket No. FAA-2021-0214.
    (3) For service information identified in this AD, contact 
Viking Air Limited Technical Support, 1959 De Havilland Way, Sidney, 
British Columbia, Canada, V8L 5V5; phone: (North America) (800) 663-
8444; fax: (250) 656-0673; email: [email protected]; 
website: https://www.vikingair.com/support/service-bulletins. 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 (816) 329-4148.

    Issued on June 21, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-13636 Filed 6-25-21; 8:45 am]
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