AD 2002-11-05 R1: Air Tractor, Inc. Model AT-501 Airplanes

This AD applies to Model AT-501 airplanes that are certificated in any category. Use Table 1 in paragraph (c)(1) of this AD for AT-501 airplanes that do not incorporate and never have incorporated Marburger winglets and use Table 2 in paragraph (c)(3) of this AD for AT-501 airplanes that incorporate or have incorporated Marburger winglets. (1) The following table applies to airplanes that do not incorporate and never have incorporated Marburger winglets along with the safe life (presented in hours time-in-service (TIS)) of the wing lower spar cap for all affected airplane models and serial numbers: Table 1.--Safe Life for Airplanes That Do Not Incorporate and Never Have Incorporated Marburger Winglets Model Serial Nos. Wing lower spar cap safe line AT-501 0002 through 0061 4,531 hours TIS. AT-501 All beginning with 0062 7,693 hours TIS. (2) If piston-powered aircraft have been converted to turbine power, you must use the limits for the corresponding serial number turbine-powered aircraft. (3) The following table applies to airplanes that incorporate or have incorporated Marburger winglets. These winglets are installed in accordance with Supplemental Type Certificate (STC) No.…