Document ID: FAA-2008-0749-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Air Tractor, Inc., Models AT-402, AT- 402A, and AT-402B Airplanes
Posted Date: 2008-07-08T04:00Z

[Federal Register: July 8, 2008 (Volume 73, Number 131)]
[Proposed Rules]               
[Page 38933-38935]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08jy08-23]                         

========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================

[[Page 38933]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0749; Directorate Identifier 2008-CE-044-AD]
RIN 2120-AA64

 
Airworthiness Directives; Air Tractor, Inc., Models AT-402, AT-
402A, and AT-402B Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain Air Tractor, Inc., (Air Tractor) Models AT-402, AT-402A, and 
AT-402B airplanes. This proposed AD would require you to repetitively 
visually inspect the rudder and vertical fin hinge attaching structure 
for loose fasteners and inspect the rudder or vertical fin skins, 
spars, hinges or brackets for cracks and/or corrosion. The AD would 
also require you to replace any damaged parts found as a result of the 
inspections and install an external doubler at the upper rudder hinge. 
Installation of the external doubler at the upper rudder hinge is 
terminating action for the repetitive inspection requirements. This 
proposed AD results from a report of a Model AT-402 airplane with a 
loose upper rudder hinge caused by fatigue. We are proposing this AD to 
detect and correct loose fasteners; any cracks in the rudder or 
vertical fin skins, spars, hinges or brackets; or corrosion of the 
rudder and vertical fin hinge attaching structure. Hinge failure 
adversely affects ability to control yaw and has led to the rudder 
folding over in flight. This condition could allow the rudder to 
contact the elevator and affect ability to control pitch with 
consequent loss of control.

DATES: We must receive comments on this proposed AD by September 8, 
2008.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD:
     Federal eRulemaking Portal: Go to http://
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 proposed AD, contact Air 
Tractor, Inc., P.O. Box 485, Olney, Texas 76374; telephone: (940) 564-
5616; facsimile: (940) 564-5612.

FOR FURTHER INFORMATION CONTACT: Andrew McAnaul, Aerospace Engineer, 
ASW-150 (c/o MIDO-43), 10100 Reunion Place, Suite 650, San Antonio, 
Texas 78216; telephone: (210) 308-3365; facsimile: (210) 308-3370.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include the docket number, ``FAA-
2008-0749; Directorate Identifier 2008-CE-044-AD'' at the beginning of 
your comments. We specifically invite comments on the overall 
regulatory, economic, environmental, and energy aspects of the proposed 
AD. We will consider all comments received by the closing date and may 
amend the proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive concerning this proposed AD.

Discussion

    We received two reports (one Air Tractor Model AT-602 airplane and 
one Model AT-802A airplane) of in-flight rudder separation at the upper 
attach hinge area and other reports of Models AT-502B, AT-602, and AT-
802/802A airplanes with loose hinges, skin cracks, or signs of repairs 
to the affected area.
    Hinge failure adversely affects ability to control yaw and has led 
to the rudder folding over in flight. This condition could allow the 
rudder to contact the elevator and affect ability to control pitch with 
consequent loss of control.
    Consequently, we issued AD 2006-23-14 (71 FR 66661, November 16, 
2006). AD 2006-23-14 requires you to repetitively visually inspect the 
rudder and vertical fin hinge attaching structure (vertical fin skins, 
spars, hinges, and brackets) for loose fasteners, cracks, and/or 
corrosion. This AD also requires you to replace any damaged parts found 
as a result of the inspection and install an external doubler at the 
upper rudder hinge.
    Since issuing AD 2006-23-14, we have received a report of a Model 
AT-402 airplane with a loose upper rudder hinge caused by fatigue. 
Therefore, we are proposing this AD to address the unsafe condition on 
the Model AT-402 airplanes.

Relevant Service Information

    We have reviewed Snow Engineering Co. Service Letter 247, 
revised June 2, 2008; and Snow Engineering Co. Process Specification 
Number 145, dated December 6, 1991. The service information describes 
procedures for:
     Inspecting (visually) the rudder and fin hinge attaching 
structure for loose fasteners, any cracks in the rudder or vertical fin 
skins, spars, hinges or brackets, or corrosion;
     Replacing any damaged parts found as a result of the 
inspection;
     Installing an external doubler at the upper rudder hinge; 
and
     Balancing of the rudder.

FAA's Determination and Requirements of the Proposed AD

    We are proposing this AD because we evaluated all information and 
determined the unsafe condition described previously is likely to exist 
or develop on other products of the same type design. This proposed AD 
would require you to repetitively visually inspect the rudder and 
vertical fin hinge attaching structure for loose fasteners, any cracks 
in the rudder or vertical fin skins, spars, hinges or brackets, or 
corrosion. This proposed AD would also require you to replace any 
damaged parts found as a result of the inspection

[[Page 38934]]

and install an external doubler at the upper rudder hinge. Installation 
of the external doubler at the upper rudder hinge is terminating action 
for the repetitive inspection requirements.

Costs of Compliance

    We estimate that this proposed AD would affect 220 airplanes in the 
U.S. registry.
    We estimate the following costs to do the proposed inspection:

----------------------------------------------------------------------------------------------------------------
                                                                                 Total cost per   Total cost on
                  Labor cost                              Parts cost                airplane      U.S. operators
----------------------------------------------------------------------------------------------------------------
1 work-hour x $80 per hour = $80.............  Not applicable.................             $80          $17,600
----------------------------------------------------------------------------------------------------------------

    Any required repairs will vary depending upon the damage found, and 
any replacements required will vary based on the results of the 
inspection. Based on this, we have no way of determining the potential 
repair and/or replacement costs for each airplane or the number of 
airplanes that will need the repairs and/or replacements based on the 
result of the inspections.
    We estimate the following costs to do the proposed installation of 
the external doubler at the upper rudder hinge:

------------------------------------------------------------------------
                                                          Total cost per
              Labor cost                   Parts cost        airplane
------------------------------------------------------------------------
5 work-hours x $80 per hour = $400....            $217             $617
------------------------------------------------------------------------

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.
    We are 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

    We have 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 that the proposed 
regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979); 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket.

Examining the AD Docket

    You may examine the AD docket that contains the proposed AD, the 
regulatory evaluation, any comments received, and other information on 
the Internet at http://www.regulations.gov; or in person at the Docket 
Management Facility between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Office (telephone (800) 647-5527) 
is located at the street address stated in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, 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 AD:

Air Tractor, Inc.: Docket No. FAA-2008-0749; Directorate Identifier 
2008-CE-044-AD.

Comments Due Date

    (a) We must receive comments on this airworthiness directive 
(AD) action by September 8, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Models AT-402, AT-402A, and AT-402B 
airplanes, serial numbers 0694 through 1176, that are certificated 
in any category.

Unsafe Condition

    (d) This AD results from a report of a Model AT-402 airplane 
with a loose upper rudder hinge caused by fatigue. We are issuing 
this AD to detect and correct loose fasteners; any cracks in the 
rudder or vertical fin skins, spars, hinges or brackets; or 
corrosion of the rudder and vertical fin hinge attaching structure. 
Hinge failure adversely affects ability to control yaw and has led 
to the rudder folding over in flight. This condition could allow the 
rudder to contact the elevator and affect ability to control pitch 
with consequent loss of control.

Compliance

    (e) To address this problem, you must do the following, unless 
already done:

[[Page 38935]]

------------------------------------------------------------------------
             Actions                  Compliance          Procedures
------------------------------------------------------------------------
(1) Inspect visually the rudder   Initially inspect   Follow Snow
 and vertical fin hinge            when the airplane   Engineering Co.
 attachment for loose fasteners;   reaches a total     Service Letter
 and inspect the rudder or         of 3,500 hours      247,
 vertical fin skins, spars,        time-in-service     revised June 2,
 hinges or brackets for cracks     (TIS) or within     2008.
 and/or corrosion.                 the next 100
                                   hours TIS after
                                   the effective
                                   date of this AD,
                                   whichever occurs
                                   later, unless
                                   already done.
                                   Thereafter,
                                   repetitively
                                   inspect at
                                   intervals not to
                                   exceed every 100
                                   hours TIS.
                                   Installation of
                                   the external
                                   doubler at the
                                   upper rudder
                                   hinge required by
                                   paragraph
                                   (e)(2)(ii) or
                                   (e)(3) of this AD
                                   is terminating
                                   action for the
                                   repetitive
                                   inspections
                                   required by this
                                   AD.
(2) If you find any damage as a   Before further      Follow Snow
 result of any inspection          flight after any    Engineering Co.
 required by paragraph (e)(1) of   inspection          Service Letter
 this AD, you must:                required by         247,
(i) Replace any damaged parts      paragraph (e)(1)    revised June 2,
 with new parts and.               of this AD where    2008; and Snow
(ii) Do the installation of the    you find any        Engineering Co.
 external doubler at the upper     damaged parts.      Process
 rudder hinge..                    The installation    Specification
                                   of the external     Number 145, dated
                                   doubler at the      December 6, 1991.
                                   upper rudder
                                   hinge required by
                                   paragraph
                                   (e)(2)(ii) or
                                   (e)(3) of this AD
                                   terminates the
                                   action for the
                                   repetitive
                                   inspections
                                   required by this
                                   AD.
(3) Do the installation of the    When the airplane   Follow Snow
 external doubler at the upper     reaches a total     Engineering Co.
 rudder hinge.                     of 5,000 hours      Service Letter
                                   TIS after the       247,
                                   effective date of   revised June 2,
                                   this AD or within   2008; and Snow
                                   the next 100        Engineering Co.
                                   hours TIS after     Process
                                   the effective       Specification
                                   date of this AD,    Number 145, dated
                                   whichever occurs    December 6, 1991.
                                   later, unless
                                   already done. The
                                   installation of
                                   the external
                                   doubler at the
                                   upper rudder
                                   hinge required by
                                   paragraph
                                   (e)(2)(ii) or
                                   (e)(3) of this AD
                                   terminates the
                                   action for the
                                   repetitive
                                   inspections
                                   required by this
                                   AD.
(4) Do not install any rudder     As of the           Not Applicable.
 without the external doubler at   effective date of
 the upper rudder hinge required   this AD.
 by paragraph (e)(3) of this AD.
------------------------------------------------------------------------

Alternative Methods of Compliance (AMOCs)

    (f) The Manager, Fort Worth Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested using 
the procedures found in 14 CFR 39.19. Send information to ATTN: 
Andrew McAnaul, Aerospace Engineer, ASW-150 (c/o MIDO-43), 10100 
Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: (210) 
308-3365; facsimile: (210) 308-3370. Before using any approved AMOC 
on any airplane to which the AMOC applies, notify your appropriate 
principal inspector (PI) in the FAA Flight Standards District Office 
(FSDO), or lacking a PI, your local FSDO.

Related Information

    (g) To get copies of the service information referenced in this 
AD, contact Air Tractor, Inc., P.O. Box 485, Olney, Texas 76374; 
telephone: (940) 564-5616; facsimile: (940) 564-5612. To view the AD 
docket, go to U.S. Department of Transportation, Docket Operations, 
M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey 
Avenue, SE., Washington, DC 20590, or on the Internet at http://
www.regulations.gov.

    Issued in Kansas City, Missouri, on July 1, 2008.
John Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-15456 Filed 7-7-08; 8:45 am]

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