Rule2023-05987
Airworthiness Directives; Viking Air Limited (Type Certificate Previously Held by Bombardier Inc. and de Havilland Inc.) Airplanes
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
March 24, 2023
Effective
April 28, 2023
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is adopting a new airworthiness directive (AD) for Viking Air Limited (type certificate previously held by Bombardier Inc. and de Havilland Inc.) Model DHC-2 Mk. I airplanes with Supplemental Type Certificate (STC) No. SA01324CH installed. This AD was prompted by a report of damage in the main wing spar. This AD requires inspecting the wing structure for damage (drill starts, corrosion, cracks, and improperly installed fasteners), repairing damage, and reporting the inspection results if necessary. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 88 Issue 57 (Friday, March 24, 2023)</title>
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[Federal Register Volume 88, Number 57 (Friday, March 24, 2023)]
[Rules and Regulations]
[Pages 17685-17688]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-05987]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2022-0814; Project Identifier AD-2022-00205-A;
Amendment 39-22397; AD 2023-06-11]
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
Viking Air Limited (type certificate previously held by Bombardier Inc.
and de Havilland Inc.) Model DHC-2 Mk. I airplanes with Supplemental
Type Certificate (STC) No. SA01324CH installed. This AD was prompted by
a report of damage in the main wing spar. This AD requires inspecting
the wing structure for damage (drill starts, corrosion, cracks, and
improperly installed fasteners), repairing damage, and reporting the
inspection results if necessary. The FAA is issuing this AD to address
the unsafe condition on these products.
DATES: This AD is effective April 28, 2023.
ADDRESSES: AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a>
by searching for and locating Docket No. FAA-2022-0814; 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, 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: Tim Eichor, Aviation Safety Engineer,
Chicago ACO Branch, FAA, 2300 E Devon Avenue, Des Plaines, IL 60018;
phone: (847) 294-7141; email: <a href="/cdn-cgi/l/email-protection#2e5a4743004a004b474d46415c6e484f4f00494158"><span class="__cf_email__" data-cfemail="77031e1a591359121e141f18053711161659101801">[email protected]</span></a>.
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 Viking Air Limited
(type certificate previously held by Bombardier Inc. and de Havilland
Inc.) Model DHC-2 Mk. I airplanes with STC No. SA01324CH installed. The
NPRM published in the Federal Register on July 8, 2022 (87 FR 40749).
The NPRM was prompted by a report that during an annual inspection of a
Viking Air Limited Model DHC-2 Mk. I airplane, a gap was noted between
the doubler and wing near station 42.5, requiring partial removal of
the doubler and removal of the sealant between the doubler and the wing
skin. Further inspection of the internal wing structure of that area
with a borescope found damage in the forward spar caused by a drill
during initial installation of the doubler. The doubler was installed
as part of Wipaire, Inc. (Wipaire), STC No. SA01324CH. Inspection of
the rest of the operator's fleet of airplanes with STC No. SA01324CH
installed found a total of 7 out of 28 wings with drill start damage in
the same area. Later inspections on these same airplanes on the
outboard end of the doubler installation revealed improperly installed
fasteners. As only a small fraction of the affected fleet has been
inspected, the possible extent of damage in the field is unknown.
Accordingly, the FAA determined that in addition to inspecting for
drill starts and improperly installed fasteners, inspecting for
corrosion and cracks is necessary. Damage of the main structural
members of the wing could adversely affect the structural integrity of
the airplane and could result in loss of control of the airplane.
Discussion of Final Airworthiness Directive
Comments
The FAA received comments from Wipaire. The following presents the
comments received on the NPRM and the FAA's response to each comment.
Request Regarding Changing the Unsafe Condition
Wipaire requested that the unsafe condition statement in the
Background section and paragraph (e) of the proposed AD be changed from
``Damage of the main structural members of the wing could adversely
affect the structural integrity of the airplane and could result in
loss of control of the airplane'' and suggested the wording ``This
condition, if not addressed, could have a slight adverse effect on the
structural integrity of the airplane.'' Wipaire stated that although
the unsafe condition statement in the NPRM is technically correct, it
is misleading to operators affected by the proposed AD. Wipaire noted
that a structural analysis performed and approved by an FAA Designated
Engineering Representative (DER) showed that this type of damage at
this location had no appreciable effect on the overall strength of the
spar. Wipaire explained that the doubler is installed inboard of the
wing strut on the upper section of the wing and in this configuration
the spar is predominately loaded compression so crack growth would be
slow and detectable.
The FAA disagrees with the commenter's request. As only a small
fraction of the affected fleet has been inspected, the extent of damage
in the field is unknown. Accordingly, it is not accurate to say that
the damage of the main structural members of the wing will not
adversely affect the structural integrity of the wing, resulting in
both the loss of the wing and loss of control of the airplane. No
change was made to this AD regarding this issue.
[[Page 17686]]
Request Regarding Background Section
Wipaire requested the Background section of the NPRM be changed
from ``6 out of 14 wings with drill start damage,'' which is based off
of inspection results of a single operator to the broader inspection
results of ``7 out of 28 wings with drill start damage,'' because these
results are based on Wipaire's record of inspections performed by
multiple operators. Wipaire stated that, while still a statistically
small sample size, the rewording to specify 28 wings provides a more
accurate representation of the potential for damage existing fleet
wide. Wipaire also mentioned that it hoped the FAA did not issue the
NPRM using calculations based on ``6 out of 14 wings.''
The FAA agrees with the commenter's statement that, in total, 7
wings were found to be damaged based on inspection results provided by
Wipaire on January 26, 2022. The FAA has revised the Background section
of this final rule to read ``Inspection of the rest of the operator's
fleet of airplanes with STC No. SA01324CH installed found a total of 7
out of 28 wings with drill start damage in the same area.''
Regarding issuing the AD based on the data of ``6 out of 14
wings,'' the FAA clarifies that under 14 CFR 39.5, issuance of an AD is
based on the finding that an unsafe condition exists in a product and
that condition is likely to exist or develop in other products of the
same type design. The FAA does not issue an AD based upon a sample size
of airplanes. The unsafe condition addressed in this AD is based on a
report of damage in the main wing spar. This condition, if not
addressed, could adversely affect the structural integrity of the
airplane and result in loss of control of the airplane. Inspections and
repair are therefore necessary to detect and correct damage in the main
wing spar before it leads to structural failure.
Request Regarding Costs of Compliance: Increase Estimated Work Hours
Wipaire requested that the work-hours for doing the inspection be
increased from 6 work-hours for a single side of the wing (left or
right) to 12 work-hours for both sides of the wing. Wipaire justified
the request by stating that due to the inspection requirement including
the complete area under the doubler, the estimate should be increased.
The FAA agrees with the commenter's request and has increased the
estimated work-hours for the inspection from 6 to 12 in the Costs of
Compliance section in this AD.
Request Regarding Costs of Compliance: Add Costs for Developing and
Approving Repair Scheme
Wipaire requested that estimated costs for developing a repair
scheme and obtaining repair scheme approval be included in the Costs of
Compliance section. Wipaire stated that these are additional costs on
operators that were not accounted for in the NPRM.
The FAA acknowledges the commenter's concerns. The FAA recognizes
that in accomplishing the requirements of any AD, operators might incur
``incidental'' costs in addition to the ``direct'' costs that are
reflected in the cost analysis presented in the AD. However, the cost
analysis in ADs typically does not include incidental costs. No change
was made to this AD regarding this issue.
Request Regarding Reducing the Inspection Areas
Wipaire requested that the FAA understand the feasibility of
inspecting every bay (both forward and aft the spar) across the entire
area and adjust the inspection requirements accordingly. Wipaire stated
that the requirement to visually inspect the aircraft structure
underneath the entire doubler between wing stations 30.26 and 126.36
may not be able to be accomplished without removal of the wing skins
and that there are bays, especially on the forward side of the spar,
that have very limited access through a combination of existing access
panels and lightening holes in structural members. Wipaire recommended
focusing the inspection only on areas where data and prior inspections
support that damage have been found (fastener locations near the spar)
because a smaller area of focus will lead to more thorough inspections
and easier compliance for operators in the field. Wipaire further
stated that the Background section of the NPRM indicated damage was
found on the inboard side of the doubler and improperly installed
fasteners on the outboard side of the doubler and recommended focusing
on those areas for inspection.
The FAA disagrees with the commenter's request because there is
other airplane structure under the doublers that could be damaged by
the installation of STC No. SA01324CH. No change was made to this AD
regarding this issue.
Comment Regarding the Visual Inspection
Wipaire stated that a borescope is needed to comply with the visual
inspection requirement specified in the proposed AD. Wipaire explained
that a borescope would be needed in order to view the area of
inspection because there are multiple 90-degree bends due to access
bays and lightening holes. Wipaire further stated that based on its
experience, operators in Alaska might not have borescope equipment and
personnel able to use that equipment readily available, which could
lead to the inability to comply with the proposed AD as written.
The FAA acknowledges the commenter's concern. While a borescope
inspection is acceptable, paragraph (g) of this AD states that a
borescope, flashlight and mirror, or equivalent, may be used to do the
visual inspection. The FAA's intent is that any inspection method that
allows for visual inspection of 100 percent of the airplane structure
complies with the visual inspection requirement. This AD also provides
time to transport the airplane to a location with the resources and
personnel to appropriately inspect the airplane. No change was made to
this AD regarding this issue.
Request Regarding Required Actions
Wipaire requested that the FAA reword the proposed inspection
requirement to ``. . . visually inspect for drill starts, improperly
installed fasteners, and corrosion or cracks related to the damage
caused by any drill starts or improperly installed fasteners'' because
the wording for the proposed requirement to inspect for corrosion and
cracks could be interpreted broadly and could be extended beyond the
scope of the proposed AD. Wipaire stated that the proposed requirement
to inspect generally for corrosion and cracks may lead to operators
being less likely to comply with the requirements specified in the
proposed AD in a timely manner.
The FAA disagrees with the commenter's request. Any crack or
corrosion that is found, regardless if it is related to damage caused
by any drill start or improperly installed fastener, must be addressed
to keep the airplane in an airworthy condition. No change was made to
this AD regarding this issue.
Request Regarding Special Flight Permit
Wipaire requested that, if no cracks are found during the visual
inspection specified in paragraph (g) of the
[[Page 17687]]
proposed AD, special flight permits be allowed so an airplane can fly
to a maintenance facility for repair work. Wipaire stated that the
language in paragraph (g) of the proposed AD and the special flight
permit prohibition in paragraph (i) of the proposed AD are not
supported by the data it gathered during its investigation into this
issue.
The FAA disagrees with the commenter's request to allow a special
flight permit to repair the aircraft as long as cracks are not found.
Drill starts, corrosion, and improperly installed fasteners contribute
to the unsafe condition as well as cracks, and if any of these are
found during the inspection, then they must be corrected before further
flight after the inspection. The compliance time of this AD is 12
months and was established to coincide with the next annual inspection.
Therefore, at the time of the inspection, the airplane should already
be at a facility where the repair could be done. Thus, a special flight
permit is not justified. No change was made to this AD regarding this
issue.
Conclusion
The FAA reviewed the relevant data, considered any comments
received, and determined that air safety requires adopting this AD as
proposed. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these products. Except for minor editorial changes, and
any other changes described previously, this AD is adopted as proposed
in the NPRM. None of the changes will increase the economic burden on
any operator.
Related Service Information
The FAA reviewed a Wipaire letter, dated September 7, 2021. This
letter requests that operators inspect the front wing spar (strap) and
front (forward) spar aft flange for drill holes due to the installation
of the top wing strap installed using Wipaire Drawing 5D1-790, which is
an attachment to the letter. This letter also requests reporting all
findings of damage to Wipaire.
Differences Between This AD and the Service Information
The Wipaire letter, dated September 7, 2021, specifies inspecting
the front spar and front spar aft flange between wing stations 42.5 and
56. This AD requires inspecting all airplane structure under the
installed doubler between wing stations 30.26 and 126.36.
Impact on Intrastate Aviation in Alaska
Airplanes modified by Wipaire STC No. SA01324CH are often used to
transport cargo and supplies to remote areas of Alaska. The FAA
estimates that roughly half of the U.S.-registered airplanes modified
by STC No. SA01324CH are operating in Alaska. Since damage to the main
structural members of the wing could result in loss of the airplane
wing and therefore, loss of control of the airplane, the FAA has
determined that the need to correct the unsafe conditions outweighs any
impact on aviation in Alaska.
Costs of Compliance
The FAA estimates that this AD affects 96 airplanes of U.S.
registry.
The FAA estimates the following costs to comply with this AD:
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Inspection...................... 12 work-hours x $85 Not Applicable........... $1,020 $97,920
per hour = $1,020.
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The FAA estimates the following costs to do any necessary repairs
that would be required based on the results of the inspection. The
agency has no way of determining the number of airplanes that might
need these repairs.
On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Cost per
Action Labor cost Parts cost product
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Repair damage........................ 100 work-hours x $85 per $35,000........................ $43,500
hour = $8,500.
Report inspection results............ 1 work-hour x $85 per Not Applicable................. 85
hour = $85.
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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
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
[[Page 17688]]
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, and
(2) 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:
2023-06-11 Viking Air Limited (Type Certificate Previously Held by
Bombardier Inc. and de Havilland Inc.): Amendment 39-22397; Docket
No. FAA-2022-0814; Project Identifier AD-2022-00205-A.
(a) Effective Date
This airworthiness directive (AD) is effective April 28, 2023.
(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-
2 Mk. I airplanes, all serial numbers, certificated in any category,
with Supplemental Type Certificate (STC) No. SA01324CH installed.
(d) Subject
Joint Aircraft System Component (JASC) Code 5711, Wing Spar.
(e) Unsafe Condition
This AD was prompted by a report of damage in the main wing
spar. The FAA is issuing this AD to detect and address damage (drill
starts, corrosion, cracks, and improperly installed fasteners) to
the main structural members of the wing. This condition, if not
addressed, could adversely affect the structural integrity of the
airplane and result in loss of control of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
Within 12 months after the effective date of this AD, using a
borescope, flashlight and mirror, or equivalent, visually inspect
the aircraft structure under the installed doubler between wing
stations 30.26 and 126.36 for drill starts, corrosion, cracks, and
improperly installed fasteners. Pay particular attention to the spar
cap, spar flange, and stringers, and include all structural items in
the wing. If there is a drill start, any corrosion, a crack, or an
improperly installed fastener, before further flight, repair using a
method approved by the Manager, Chicago ACO Branch, FAA. For a
repair method to be approved by the Manager, Chicago ACO Branch, as
required by this paragraph, the Manager's approval letter must
specifically refer to this AD.
Note 1 to paragraph (g): Wipaire, Inc., letter, dated September
7, 2021, provides additional information on this subject, including
examples of damage.
(h) Reporting Requirement
If, during the inspection required by paragraph (g) of this AD,
any damage is found, within 30 days after doing the inspection or
within 30 days after the effective date of this AD, whichever occurs
later, report the following information to the person identified in
paragraph (k)(1) of this AD:
(1) Name and address of owner.
(2) Date of the inspection.
(3) Name, address, telephone number, and email address of person
submitting the report.
(4) Airplane serial number, registration number, STC
installation date, and total hours time-in-service on the airplane
at the time of the inspection.
(5) Description of damage. Include affected structure, location,
dimensions, and photos of damage (or sketches, if photos are not
possible).
(i) Special Flight Permit
Special flight permits are prohibited.
(j) Alternative Methods of Compliance (AMOCs)
(1) The Manager, Chicago 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 Tim Eichor,
Aviation Safety Engineer, Chicago ACO Branch, FAA, 2300 E Devon
Avenue, Des Plaines, IL 60018; phone: (847) 294-7141; email:
<a href="/cdn-cgi/l/email-protection#c9bda0a4e7ade7aca0aaa1a6bb89afa8a8e7aea6bf"><span class="__cf_email__" data-cfemail="fc889591d298d299959f94938ebc9a9d9dd29b938a">[email protected]</span></a>.
(2) For service information identified in this AD that is not
incorporated by reference, contact Wipaire, Inc., 1700 Henry Avenue,
Fleming Field (KSGS), South St. Paul, MN 55075; phone: (651) 451-
1205; fax: (651) 457-7858; email: <a href="/cdn-cgi/l/email-protection#4d3e3a243939280d712c6d253f282b70" http: wipaire.com">wipaire.com</a>">switte@<a href="http://wipaire.com">wipaire.com</a></a>; website:
<a href="http://wipaire.com">wipaire.com</a>. You may view this referenced 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.
(l) Material Incorporated by Reference
None.
Issued on March 20, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2023-05987 Filed 3-23-23; 8:45 am]
BILLING CODE 4910-13-P
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