Airworthiness Directive · Amendment 39-14826 · Air Tractor, Inc. Models AT-502, AT-502A, AT-502B, AT-602, AT-802, and AT-802A Airplanes
Air Tractor, Inc. Models AT-502, AT-502A, AT-502B, AT-602, AT-802, and AT-802A Airplanes
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. |
The FAA adopts 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 AD 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. This AD results from two reports of in-flight rudder separation from the vertical fin at the upper attach hinge area, and other reports of 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; and/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.
To address this problem, you must do the following:
| Actions | Compliance | Procedures |
|---|---|---|
| (1) Inspect visually the rudder and vertical hinge attachment for loose fasteners; and inspect the rudder or vertical fin skins, spars, hinges or brackets for cracks and/or corrosion | Initially inspect upon reaching 3,500 hours time-in-service (TIS), or within the next 100 hours TIS after December 21, 2006 (the 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 | Follow Snow Engineering Co. Service Letter #247, dated August 14, 2005, revised May 17, 2006. |
| (2) If you find any damage as a result of any inspection required by paragraph (e)(1) of this AD, you must: (i) Replace any damaged parts with new parts; and (ii) Do the installation of the external doubler at the upper rudder hinge. | Before further flight after any inspection required by paragraph (e)(1) of this AD where you find any damaged parts. The installation of the external 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 | Follow 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. |
| (3) Do the installation of the external doubler at the upper rudder hinge | Upon accumulating 5,000 hours TIS or within the next 100 hours TIS after the effective date of this AD, whichever occurs 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 is the terminating action for the repetitive inspections required by this AD | Follow 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. |
| (4) Do not install any rudder without the external doubler at the upper rudder hinge required by paragraph (e)(3) of this AD | As of December 21, 2006 (the effective date of this AD) | Not Applicable. |
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
