Document ID: FAA-2020-0710-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: Air Tractor, Inc. Airplanes
Posted Date: 2020-07-28T04:00Z

[Federal Register Volume 85, Number 145 (Tuesday, July 28, 2020)]
[Proposed Rules]
[Pages 45347-45350]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-16209]

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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

[[Page 45348]]

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
----------------------------------------------------------------------------------------------------------------
                                                                                                  Cost on U.S.
             Action                    Labor cost            Parts cost     Cost per  product      operators
----------------------------------------------------------------------------------------------------------------
Dye penetrant inspection.......  4 work-hours x $85 per  Not applicable...  $340 per           $565,080 per
                                  hour = $340 per                            inspection cycle.  inspection
                                  inspection cycle.                                             cycle.
Visual inspection..............  .5 work-hour x $85 per  Not applicable...  42.50............  70,635 per
                                  hour = $42.50 per                                             inspection
                                  inspection cycle.                                             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]
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                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replacement of torque tube....................  3 work-hours x $85 per hour =             $1,292          $1,547
                                                 $255.
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[[Page 45349]]

                                       On-Condition Costs for Model AT-602
                                            [Potential 236 Airplanes]
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                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replacement of torque tube....................  3 work-hours x $85 per hour =             $1,140          $1,395
                                                 $255.
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           On-Condition Costs for Models AT-501, AT-502, AT-502A, AT-502B, AT-503, AT-503A, and AT-504
                                            [Potential 512 Airplanes]
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replacement of torque tube....................  3 work-hours x $85 per hour =               $955          $1,210
                                                 $255.
----------------------------------------------------------------------------------------------------------------

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]
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replacement of torque tube....................  3 work-hours x $85 per hour =               $927          $1,182
                                                 $255.
----------------------------------------------------------------------------------------------------------------

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

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):

Air Tractor, Inc.: Docket No. FAA-2020-0710; Product Identifier 
2019-CE-037-AD.

(a) Comments Due Date

    The FAA must receive comments by September 11, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to 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, all 
serial numbers, certificated in any category.

(d) Subject

    Joint Aircraft System Component (JASC) of America Code: 2750, TE 
flap control system.

(e) Unsafe Condition

    This AD was prompted by reports from Air Tractor that the flap 
actuator attachment brackets can crack and detach from the torque 
tube. The FAA is issuing this AD to detect and correct cracks in the 
flap actuator attachment brackets. The unsafe condition, if not 
addressed, could lead to the brackets detaching from the torque 
tube, which could result in an uncommanded retraction of the flaps 
with consequent loss of airplane control.

(f) Compliance

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

(g) Actions

    (1) Within 300 hours time-in-service (TIS) after the effective 
date of this AD and thereafter at intervals not to exceed 900 hours 
TIS, perform a dye penetrant inspection of each flap torque tube 
actuator attachment bracket for cracks in accordance with steps 
4B(2) through (7) of Air Tractor, Inc., Service Letter #347, 
Revision A, dated December 9, 2019 (Air Tractor SL #347, Rev A).
    (i) If there is a crack, before further flight, replace the flap 
torque tube with a flap torque tube that has zero hours TIS.
    (ii) If there are no cracks, before further flight, complete the 
actions in steps 4B(9) and (10) of Air Tractor SL #347, Rev A.
    (2) Within 300 hours TIS after the inspection required by 
paragraph (g)(1) of this AD and thereafter at intervals not to 
exceed 300 hours TIS, visually inspect each

[[Page 45350]]

flap torque tube actuator attachment bracket for cracks in 
accordance with steps 4A(1) through (3) of Air Tractor SL #347, Rev 
A. If there is a crack, before further flight, replace the flap 
torque tube with a flap torque tube that has zero hours TIS.
    (3) Replacing a flap torque tube does not terminate the 
repetitive visual inspections or dye penetrant inspections required 
by this AD.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, of the Fort Worth ACO Branch, AIR-7F0, has the 
authority to approve AMOCs for this AD, if requested using the 
procedures found in 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, sent it to the attention of: 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.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector (PI), or lacking a PI, your local Flight 
Standards District Office.

(i) Related Information

    For more information about this AD, 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.

    Issued on July 22, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-16209 Filed 7-27-20; 8:45 am]
BILLING CODE 4910-13-P