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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-0710; Product Identifier 2019-CE-037-AD]
RIN 2120-AA64
Airworthiness Directives; Air Tractor, Inc. 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 Air Tractor, Inc. (Air Tractor) Models AT-250, AT-300, AT-301,
AT-302, AT-400, AT-400A, AT-401, AT-401A, AT-401B, AT-402, AT-402A, AT-
402B, AT-501, AT-502, AT-502A, AT-502B, AT-503, AT-503A, AT-504, AT-
602, AT-802, and AT-802A airplanes. This proposed AD was prompted by
reports of cracks in the flap torque tube actuator attachment brackets
that may cause the flap actuator to detach from the flap torque tube.
This proposed AD would require repetitive visual and dye penetrant
inspections of the flap actuator attachment bracket welds for cracks
and replacement if cracks are identified. 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 September
11, 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.
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 Air
Tractor, Inc., P.O. Box 485, Olney, TX 76374: telephone: 940-564-5616:
email: info@airtractor.com: internet: https://airtractor.com/. You may
view this service information at the FAA, Airworthiness Products
Section, Operational Safety Branch, 901 Locust St, 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 on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2020-0710;
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, 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: Kenneth A. Cook, Aerospace Engineer,
Fort Worth ACO Branch, AIR-7F0, FAA, 10101 Hillwood Pkwy., Fort Worth,
TX 76177; phone: 817-222-5475; email: kenneth.a.cook@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include "Docket No. FAA-2020-0710;
Product Identifier 2019-CE-037-AD" 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 we receive, without change, to
https://regulations.gov, including any personal information you
provide. The FAA will also post a report summarizing each substantive
verbal contact it receives about this proposed AD
Confidential Business Information
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 [insert name and address of aerospace engineer listed
above]. Any commentary that the FAA receives which is not specifically
designated as CBI will be placed in the public docket for this
rulemaking.
Discussion
The FAA has received multiple reports of cracks in the brackets
attaching the flap actuator motor to the flap torque tube on several
models of Air Tractor airplanes.
One of the reports was on a Model AT-802A airplane where the
brackets separated from the torque tube at the welds. The flaps
suddenly retracted while maneuvering, and the pilot temporarily lost
control of the airplane. The pilot was able to regain control of the
airplane before it impacted the ground. Since then, there have been 13
reported airplanes with cracks in the flap torque tube attachment
brackets.
The design of the flap actuator motor brackets on the Model AT-802A
airplane is the same as on Models AT-250, AT-300, AT-301, AT-302, AT-
400, AT-400A, AT-401, AT-401A, AT-401B, AT-402, AT-402A, AT-402B, AT-
501, AT-502, AT-502A, AT-503, AT-503A, AT-504, AT-602, and AT-802
airplanes.
This condition, if not addressed, could result in the flap actuator
attachment brackets detaching from the flap torque tube and lead to an
uncommanded retraction of the flaps with consequent loss of airplane
control.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Air Tractor, Inc. Service Letter #347, Revision A,
dated December 9, 2019 (Air Tractor SL #347, Rev A). The service letter
contains procedures for repetitive visual inspections and dye penetrant
inspections of the flap torque tube brackets for cracks and instructs
operators to replace the torque tube as necessary. 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 proposing 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.
Proposed AD Requirements
This proposed AD would require, within 300 hours time-in-service
(TIS) after the effective date of this AD and thereafter at intervals
not to exceed 900 hours TIS, performing a dye penetrant inspection by
following Air Tractor SL #347, Rev A. Within 300 hours TIS after the
first dye penetrant inspection and thereafter at intervals not to
exceed 300 hours TIS, this proposed AD would require performing a
visual inspection by following Air Tractor SL #347, Rev A.
Differences Between This Proposed AD and the Service Information
Air Tractor SL #347, Rev A provides an allowance (plus or minus 15
percent) for the 300-hour visual inspections, and this proposed AD
would not. Air Tractor SL #347, Rev A specifies performing the dye
penetrant inspection within 900 hours TIS, and this proposed AD would
require the initial dye penetrant inspection within 300 hours TIS. Air
Tractor SL #347, Rev A specifies replacing a cracked torque tube, while
this proposed AD would require replacing a cracked torque tube with a
torque tube that has zero hours TIS. Air Tractor SL #347, Rev A
specifies reporting any cracked welds identified during the inspections
to Air Tractor, and this proposed AD would not.
Costs of Compliance
The FAA estimates that this proposed AD affects 1,662 airplanes of
U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:
Estimated Costs
| Action |
Labor cost |
Parts cost |
Cost per product |
Cost on U.S. operators |
| Dye penetrant inspection |
4 work-hours x $85 per hour =
$340 per inspection cycle |
Not applicable |
$340 per inspection cycle |
$565,080 per inspection cycle |
| Visual inspection |
.5 work-hour x $85 per hour =
$42.50 per inspection cycle |
Not applicable |
42.50 |
70,635 per inspection cycle |
The FAA estimates the following costs
to do any necessary
replacements that would be required based on the results of the
proposed inspection. The FAA has no way of determining the number of
aircraft that might need this replacement.
On-Condition Costs for Model AT-802 and AT-802A [Potential 485 airplanes]
| Action |
Labor cost |
Parts cost |
Cost per product |
| Replacement of torque tube |
3 work-hours x $85 per hour =
$255 |
$1,292 |
$1,547 |
On-Condition Costs for Model AT-602
[Potential 236 Airplanes]
| Action |
Labor cost |
Parts cost |
Cost per product |
| Replacement of torque tube |
3 work-hours x $85 per hour =
$255 |
$1,140 |
$1,395 |
On-Condition Costs for Models
AT-501, AT-502, AT-502A, AT-502B, AT-503,
AT-503A, and AT-504 [Potential 512 Airplanes]
| Action |
Labor cost |
Parts cost |
Cost per product |
| Replacement of torque tube |
3 work-hours x $85 per hour =
$255 |
$955 |
$1,210 |
On-Condition Costs for Models
AT-250, AT-300, AT-301, AT-302, AT-400,
AT-400A, AT-401, AT-401A, AT-401B, AT-402, AT-402A, and AT-402B
[Potential 429 Airplanes]
| Action |
Labor cost |
Parts cost |
Cost per product |
| Replacement of torque
tube |
3 work-hours x $85
per hour = $255 |
$927 |
$1,182 |
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) 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 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
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 (AD):
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