AIR TRACTOR AT-502A, Maintenance Section

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Air Tractor, Inc. Maintenance Page 1
AT-502A/502B/504 March 14, 2018
INTRODUCTION
This section is presented to describe maintenance functions that are applicable to the AT-502/504 airplane.
Airframe maintenance items that are not specifically covered in this section are addressed in FAA Advisory
Circular (AC) 43.13. Additional maintenance functions for the engine, propeller, and other accessories can
be found in the specific manufacturer’s maintenance documentation.
FUEL REQUIREMENTS
See Approved Airplane Flight Manual.
OIL REQUIREMENTS
Oil used at the factory is denoted inside the oil door on the top engine cowling. If a different brand is
used, the engine and lines should be drained and a flushing procedure with the new oil should be carried out
in accordance with the Pratt & Whitney PT6A Maintenance Manual. Also see Flight Manual.
TIRE INFLATION
The main tires are inflated to a pressure of 50 psi (unloaded) or 52 psi (loaded). The tail wheel tire is
inflated to a pressure of 50 psi (loaded or unloaded).
LIFTING AND JACKING
A jack pad is provided with each aircraft for the main gear. This jack pad is to be used for changing or
removing a wheel. To install the jack pad, lay a soft rag on the inside so that it will not chip the paint from the
main gear leg and slide the jack pad up the lower end of the main gear leg until it is snug. It will be necessary
to remove and replace the lower plastic band that holds the brake line in place. The band is a Tyton T150M-0
and should be stocked as a standard spares item. After the jack pad is in place, install the bolt and nut
through the pad flanges with the bolt on the top side of the gear leg. This is to keep the pad from spreading
apart and slipping. Use a small hydraulic jack to lift the wheel off the ground. Be sure the tail wheel is locked,
and chocks are in place on the other main wheel. The hopper should be empty before jacking.
Alternately, to service the main wheel, tires or brakes, the pane may be jacked utilizing a typical
tripod general aviation wing jack of at least 3000 lb capacity and the jack point included in the delivery kit. To
accomplish this, remove the main landing gear cuff and expose the main gear spring clamp. Insert the jack
point into the head of the socket head bolt attaching the clamp block. You may need to place a dab of
grease or putty in the socket head of the bolt to temporarily hold the jack point in place. Position the jack
under the jack point and lift the wheel off the ground. Before lifting the plane be sure the other main gear is
chocked and that the tail wheel is locked. Use caution making sure the jack is stable understanding that the
main gear spring deflects latterly as the plane is lifted and lowered.
CAUTION: Care should always be taken when the aircraft is lifted to
prevent damage to the aircraft or harm to people near it.
To jack the tail wheel, place a small board (a short 2x4) under the tail spring about mid-way between
the forward spring attach bolt and the main clamp block that attaches the spring to the fuselage. Place the
jack on the board and lift the wheel. Be sure the parking brake is set before jacking.