[Federal Register Volume 85, Number 159 (Monday, August 17, 2020)]
[Rules and Regulations]
[Pages 49962-49965]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-17904]



[[Page 49962]]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0715; Project Identifier AD-2020-00484-A; 
Amendment 39-21190; AD 2020-16-06]
RIN 2120-AA64


Airworthiness Directives; Aviat Aircraft Inc.

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Aviat Aircraft Inc. Models A-1, A-1A, A-1B, A-1C-180, and A-1C-200 
airplanes.
    This AD requires repetitive inspections of the forward horizontal 
stabilizer support assembly and the rear horizontal stabilizer support 
tube and reporting information to the FAA. This AD was prompted by 
field reports of complete failure of both the forward support assembly 
and the rear support tube due to fatigue. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective September 1, 2020.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of September 1, 
2020.
    The FAA must receive comments on this AD by October 1, 2020.

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.
     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: 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 final rule, contact 
Aviat Aircraft Inc., Al Humbert, 672 South Washington Street, Afton, 
WY, 83110, United States; phone: (307) 885-3151; email: 
dmir@aviataircraft.com; internet: https://aviataircraft.com. You may 
view this 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 and locating Docket No. FAA-2020-
0715.

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-2020-
0715; 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 
street address for the Docket Operations is listed above. Comments will 
be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Mark Dalrymple, Aerospace Engineer, 
Denver ACO Branch, FAA, 26805 E. 68th Avenue, Denver, CO 80249; phone: 
(303) 342-1090; email: mark.dalrymple@faa.gov.

SUPPLEMENTARY INFORMATION: 

Discussion

    The FAA received three field reports from Aviat Aircraft Inc. of 
complete failure of the rear horizontal stabilizer inboard support 
tube. The first incident, discovered during a scheduled inspection, 
occurred in 2005, and the second incident, discovered while the 
airplane was being re-skinned, occurred in 2009. The third incident was 
discovered during a pre-flight inspection in 2012 and included a 
complete failure of the forward horizontal stabilizer inboard support 
assembly. Failure analysis of both parts from the 2012 incident 
concluded they failed due to fatigue. In addition to these complete 
failures of the rear support tube, the FAA received two field reports 
from Aviat Aircraft Inc. of cracks in the rear support tube, discovered 
during inspections, in 2005 and 2013. Aviat Aircraft Inc. subsequently 
issued Service Bulletin No. 28, Revision A, dated April 2, 2015, which 
requires a one-time inspection of the rear stabilizer inboard support 
tube in response to the multiple reports of failures and cracks.
    In addition to the 2012 incident, which involved a failure of both 
supports, the FAA received two other field reports from Aviat Aircraft 
Inc. of complete failure of the forward horizontal stabilizer inboard 
support assembly, one in 2000 and one in 2019. In the first incident, 
the failure occurred during ground handling after flight. In the second 
incident the failure was discovered while the aircraft was being placed 
in a hanger.
    Failure of either the forward or rear support transfers loads to 
the other support, increasing the likelihood that both could fail. This 
condition, if not addressed, could result in stabilizer departure and 
loss of airplane control.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Aviat Aircraft Inc. Service Bulletin No. 28, 
Revision A, dated April 2, 2015 (Aviat SB No. 28, Revision A). This 
service information contains procedures for inspecting and repairing 
the rear stabilizer support tube. 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.

FAA's Determination

    The FAA is issuing this AD because it evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

AD Requirements

    This AD requires inspection for cracks and replacement if necessary 
of the forward horizontal stabilizer support assembly. This AD also 
requires inspecting the rear horizontal stabilizer support tube for 
corrosion and damage and repair if necessary. This AD also requires 
reporting the inspection results to the FAA.

FAA's Justification and Determination of the Effective Date

    An unsafe condition exists that requires the immediate adoption of 
this AD without providing an opportunity for public comments prior to 
adoption. The FAA has found that the risk to the flying public 
justifies waiving notice and comment prior to adoption of this rule 
because FAA risk assessment indicates there is an unacceptable short-
term risk of developing fatigue cracks through 25 percent of the cross 
sectional area of the rear support tube on airplanes that have engaged 
in tow operations. In addition, further FAA risk assessment indicates 
there is an unacceptable short-term risk of developing fatigue cracks 
through 25

[[Page 49963]]

percent of the cross sectional area of the forward support assembly on 
all airplanes. In the majority of known incidents at either location, 
the support failed completely. Failure of either the forward or rear 
support transfers loads to the other support, increasing the likelihood 
that both could fail, which has occurred in one known incident. A 
combined failure of both the forward and rear supports could result in 
stabilizer departure and loss of airplane control. Therefore, the FAA 
finds good cause that notice and opportunity for prior public comment 
are impracticable. In addition, for the reasons stated above, the FAA 
finds that good cause exists for making this amendment effective in 
less than 30 days.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety and was not preceded by notice and an opportunity for public 
comment. However, we invite you to send any written data, views, or 
arguments about this final rule. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No.FAA-2020-0715; 
Product Identifier AD-2020-00484-A'' at the beginning of your comments. 
The FAA will consider all comments received by the closing date and may 
amend this proposed AD 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 FAA will also post a report summarizing each substantive 
verbal contact we receive about this final rule.

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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Mark 
Dalrymple, Aerospace Engineer, Denver ACO Branch, FAA, 26805 E. 68th 
Avenue, Denver, CO 80249. Any commentary that the FAA receives which is 
not specifically designated as CBI will be placed in the public docket 
for this rulemaking.
    The FAA will post all comments received, without change, to https://www.regulations.gov, including any personal information you provide. 
The FAA will also post a report summarizing each substantive verbal 
contact we receive about this AD.

Differences Between This AD and the Service Information

    The service information only applies to certain serial numbers of 
the airplane models identified in this AD, while this AD applies to all 
serial numbers of Aviat Aircraft Inc. Model A-1, A-1A, A-1B, A-1C-180, 
and A-1C-200 airplanes. The service information only requires 
inspecting the rear stabilizer support tube, while this AD requires 
inspecting the forward stabilizer support assembly in addition to the 
rear stabilizer support tube. The service information only requires a 
one-time inspection, while this AD requires both initial and repetitive 
inspections.

Costs of Compliance

    The FAA estimates that this AD affects 941 airplanes of U.S. 
registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Inspect forward horizontal stabilizer   1 work-hour x $85.00 per          $25.00         $110.00     $103,510.00
 inboard support assembly for cracks.    hour = $85.00.
Inspect rear horizontal stabilizer      0.5 work-hour x $85.00              0.00           42.50       39,992.50
 inboard support tube weld joints for    per hour = $42.50.
 corrosion and damage.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary repairs 
or replacements that would be required based on the results of the 
inspection. The FAA has no way of determining the number of airplanes 
that might need these replacements:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace forward horizontal stabilizer support   2 work-hours x $85.00 per hour =         $296.00         $466.00
 tube.                                           $170.00.
Repair rear horizontal stabilizer support tube  4.5 work-hours x $85.00 per hour          163.00          545.50
 weld joints and install new support tube        = $382.50.
 insert.
Report if cracks are found....................  0.5 work-hour x $85.00 per hour             0.00           42.50
                                                 = $42.50.
----------------------------------------------------------------------------------------------------------------

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 be 
approximately .5 hour per response, including the time for reviewing 
instructions, searching existing data sources, gathering and 
maintaining the data needed, completing and reviewing the collection of 
information. All

[[Page 49964]]

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 Flexibility Act

    The requirements of the Regulatory Flexibility Act (RFA) do not 
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt 
a rule without prior notice and comment. Because FAA has determined 
that it has good cause to adopt this rule without notice and comment, 
RFA analysis is not required.

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 affect intrastate aviation in Alaska.

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

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 (AD):

2020-16-06 Aviat Aircraft Inc.: Amendment 39-21190; Docket No. FAA-
2020-0715; Project Identifier AD-2020-00484-A.

(a) Effective Date

    This AD is effective September 1, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Aviat Aircraft Inc., Models A-1, A-1A, A-1B, 
A-1C-180, and A-1C-200 airplanes, all serial numbers, certificated 
in any category.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 5510, Horizontal Stabilizer Structure.

(e) Unsafe Condition

    This AD was prompted by reports of complete failure of the 
forward horizontal stabilizer support assembly due to fatigue in 
combination with complete failure of the rear horizontal stabilizer 
support tube due to fatigue. The FAA is issuing this AD to prevent 
cracking of the forward and rear inboard supports, which could 
result in failure of the stabilizer supports, detachment of the 
stabilizer, and loss of airplane control.

(f) Compliance

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

(g) Inspection and Repair

    For airplanes with 400 or more hours time-in-service (TIS), do 
the following inspection within 30 days after September 1, 2020 (the 
effective date of this AD) or within 20 hours TIS after September 1, 
2020 (the effective date of this AD), whichever occurs first. For 
airplanes with less than 400 hours TIS, do the following inspections 
within 30 days after accumulating 400 hours TIS or within 20 hours 
TIS after accumulating 400 hours TIS, whichever occurs first. After 
the initial inspection, repeat the inspections at intervals not to 
exceed 12 months or 100 hours TIS, whichever occurs first.
    (1) Below and just aft of the horizontal stabilizer leading 
edge, remove each inspection hole cover if installed, or cut out the 
inside of each inspection ring if not cut out, on both sides of the 
fuselage. You do not need to remove the stabilizer support assembly. 
Locate the forward horizontal stabilizer support assembly. Using a 
light and a mirror or a borescope, inspect the stabilizer support 
assembly for cracks in the large tube portion of the assembly. Pay 
particular attention to the toe of the welded bushings where the 
stabilizer support assembly is bolted to the fuselage frame.
    (i) If no cracks are found, install inspection hole cover, part 
number (P/N) 61659 and mounting screws, P/N 59146.
    (ii) If any cracks are found, before further flight, replace the 
stabilizer support assembly with the same part-numbered part, either 
P/N 35086-501 or P/N 38086-501 as applicable. Replace both self-
locking nuts with self-locking nuts that have zero hours TIS. 
Replacing the forward stabilizer support assembly requires removal 
and reinstallation of other horizontal stabilizer components. 
Replace all self-locking nuts with self-locking nuts that have zero 
hours TIS upon reinstallation of these components.
    (2) Inspect the rear horizontal stabilizer support tube weld 
joints for corrosion and damage in accordance with the Instructions, 
steps 1.a. and 1.b., of Aviat Aircraft Inc. Service Bulletin No. 28, 
Revision A, dated April 2, 2015. If there is any corrosion or damage 
on a weld joint, before further flight, repair the weld joint and 
install a repair tube inside the stabilizer support tube as depicted 
in the figure on page 3 of Aviat Aircraft Inc.
    Service Bulletin No. 28, Revision A, dated April 2, 2015. 
Repairing the rear horizontal stabilizer support tube requires 
removal and reinstallation of other horizontal stabilizer 
components. Replace all self-locking nuts with self-locking nuts 
that have zero hours TIS upon reinstallation of these components.

(h) Reporting Requirement

    If a crack is found during any inspection required by paragraph 
(g) of this AD, within 10 days, report the following information to 
the FAA at the address listed in paragraph (l) of this AD:
    (1) Aircraft Make and Model
    (2) Aircraft N-number
    (3) Aircraft Serial Number
    (4) Total hours TIS
    (5) Total takeoff and landing cycles (if known)
    (6) Aircraft used for Tow operations? Yes or No
    (7) If the Aircraft is used for Tow operations, report heaviest 
Glider Max Gross takeoff weight or banner maximum weight.
    (8) Describe the crack location(s) and report the length of the 
crack(s) in the forward horizontal stabilizer support assembly, rear 
horizontal stabilizer support tube, or both.

(i) Special Flight Permit

    In accordance with 14 CFR 39.23, special flight permits are 
prohibited.

(j) Paperwork Reduction Act Burden Statement

    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

[[Page 49965]]

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 be 
approximately .5 hour per response, including the time for reviewing 
instructions, searching existing data sources, gathering and 
maintaining the data needed, 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.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Denver 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 (l) 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.

(l) Related Information

    For more information about this AD, contact Mark Dalrymple, 
Aerospace Engineer, Denver ACO Branch, FAA, 26805 E. 68th Avenue, 
Denver, CO 80249; phone: (303) 342-1090; email: 
mark.dalrymple@faa.gov.

(m) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference 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) Aviat Aircraft Inc. Service Bulletin No. 28, Revision A, 
dated April 2, 2015.
    (ii) [Reserved]
    (3) For Aviat Aircraft Inc. service information identified in 
this AD, contact Aviat Aircraft Inc., Al Humbert, 672 South 
Washington Street, Afton, WY 83110, United States; phone: (307) 885-
3151; email: dmir@aviataircraft.com; internet: https://aviataircraft.com.
    (4) You may view this service information at 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.
    (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: fedreg.legal@nara.gov, or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on July 28, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-17904 Filed 8-14-20; 8:45 am]
BILLING CODE 4910-13-P


