Federal Aviation Administration (FAA), Department of Transportation (DOT).
Notice of proposed rulemaking (NPRM).
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,
We must receive comments on this proposed AD by October 10, 2006.
Use one of the following addresses to comment on this proposed AD:
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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.
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.
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
We will post all comments we receive, without change, to
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.
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.
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.
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:
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:
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
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.
You may examine the AD docket that contains the proposed AD, the regulatory evaluation, any comments received, and other information on the Internet at
Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:
1. The authority citation for part 39 continues to read as follows:
: 49 U.S.C. 106(g), 40113, 44701.
2. The FAA amends § 39.13 by adding the following new AD:
(a) We must receive comments on this airworthiness directive (AD) action by October 10, 2006.
(b) None.
(c) This AD affects the following airplane models and serial numbers that are certificated in any category:
(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.
(e) To address this problem, you must do the following:
(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.
(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