[Federal Register Volume 71, Number 153 (Wednesday, August 9, 2006)]
[Proposed Rules]
[Pages 45451-45454]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-12940]


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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-25260; Directorate Identifier 2006-CE-37-AD]
RIN 2120-AA64


Airworthiness Directives; Air Tractor, Inc. Models AT-502, AT-
502A, AT-502B, AT-602, AT-802, and AT-802A 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-502, AT-502A, AT-
502B, AT-602, AT-802, and AT-802A airplanes. 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. 
The AD would also require you to replace any damaged parts found as a 
result of the inspection 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 two reports (one Model AT-602 airplane 
and one Model AT-802A airplane) of in-flight rudder separation from the 
vertical fin 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. We are proposing 
this AD to detect and correct loose fasteners; any cracks in the rudder 
or vertical fin skins, spars,

[[Page 45452]]

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 of the airplane.

DATES: We must receive comments on this proposed AD by October 10, 
2006.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD:
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, 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-
2006-25260; Directorate Identifier 2006-CE-37-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://dms.dot.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 have 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 of the airplane.

Relevant Service Information

    We have reviewed Snow Engineering Co. Service Letter 247, 
dated August 14, 2005, revised May 17, 2006, 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 AD would also require you to replace any damaged parts 
found as a result of the inspection 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 945 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         $75,600
----------------------------------------------------------------------------------------------------------------

    We have no way of determining the number of airplanes that may need 
any replacements that would be required based on the results of the 
proposed inspection.
    We estimate the following costs to do the installation of the 
external doubler at the upper rudder hinge:

----------------------------------------------------------------------------------------------------------------
                                                                                  Total cost per   Total cost on
                 Labor cost                               Parts cost                 airplane     U.S. operators
----------------------------------------------------------------------------------------------------------------
5 work-hours x $80 per hour = $400.........  $217...............................            $617        $583,065
----------------------------------------------------------------------------------------------------------------

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

[[Page 45453]]

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://dms.dot.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) 647-5227) 
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-2006-25260; Directorate Identifier 
2006-CE-37-AD.

Comments Due Date

    (a) We must receive comments on this airworthiness directive 
(AD) action by October 10, 2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD affects the following airplane models and serial 
numbers that are certificated in any category:

------------------------------------------------------------------------
                 Model                             Serial Nos.
------------------------------------------------------------------------
(1) AT-502 and AT-502B.................  502/502B-0003 through 502/502B-
                                          2600.
(2) AT-502A............................  502A-0003 through 502A-2582.
(3) AT-602.............................  602-0337 through 602-1138.
(4) AT-802 and AT-802A.................  802/802A-0001 through 802/802A-
                                          0215.
------------------------------------------------------------------------

Unsafe Condition

    (d) This AD results from two reports (one Model AT-602 airplane 
and one Model AT-802A airplane) of in-flight rudder separations 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. 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 of the airplane.

Compliance

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

------------------------------------------------------------------------
             Actions                  Compliance          Procedures
------------------------------------------------------------------------
(1) Inspect visually the rudder   Initially inspect   Follow Snow
 and vertical hinge attachment     upon reaching       Engineering Co.
 for loose fasteners; any cracks   3,500 hours time-   Service Letter
 in the rudder or vertical fin     in-service (TIS),   247,
 skins, spars, hinges or           or within the       dated August 14,
 brackets, or corrosion.           next 100 hours      2005, revised May
                                   TIS after the       17, 2006.
                                   effective date of
                                   this AD,
                                   whichever occurs
                                   later, unless
                                   already done.
                                   Thereafter,
                                   repetitively
                                   inspect 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)    dated August 14,
 with new parts; and               of this AD where    2005, revised May
(ii) Do the installation of the    you find any        17, 2006, and
 external doubler at the upper     damaged parts.      Snow Engineering
 rudder hinge.                     The installation    Co. Process
                                   of the external     Specification
                                   doubler at the      Number 145, dated
                                   upper rudder        December 6, 1991.
                                   hinge required by
                                   paragraph
                                   (e)(2)(ii) or
                                   (e)(3) of this AD
                                   is the
                                   terminating
                                   action for the
                                   repetitive
                                   inspections
                                   required by this
                                   AD.

[[Page 45454]]

 
(3) Do the installation of the    Upon accumulating   Follow Snow
 external doubler at the upper     5,000 hours TIS     Engineering Co.
 rudder hinge.                     or within the       Service Letter
                                   next 100 hours      247,
                                   TIS after the       dated August 14,
                                   effective date of   2005, revised May
                                   this AD,            17, 2006, and
                                   whichever occurs    Snow Engineering
                                   later, unless       Co. Process
                                   already done. The   Specification
                                   installation of     Number 145, dated
                                   the external        December 6, 1991.
                                   doubler at the
                                   upper rudder
                                   hinge required by
                                   paragraph
                                   (e)(2)(ii) or
                                   (e)(3) of this AD
                                   is the
                                   terminating
                                   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, 
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, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19.

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 the Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-
401, Washington, DC, or on the Internet at http://dms.dot.gov. The 
docket number is Docket No. FAA-2006-25260; Directorate Identifier 
2006-CE-37-AD.

    Issued in Kansas City, Missouri, on August 3, 2006.
John R. Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-12940 Filed 8-8-06; 8:45 am]
BILLING CODE 4910-13-P