After completion of the static rigging, a functional check of  the flight control system must be accomplished. The nature  of the functional check varies with the type of helicopter and  system concerned, but usually includes determining that:  An aircraft with a single horizontal main rotor that provides  both lift and direction of travel is a single rotor helicopter.  A secondary rotor mounted vertically on the tail counteracts  the rotational force (torque) of the main rotor to correct yaw  of the fuselage.  [Figure 2-25]  An autogyro is an aircraft with a free-spinning horizontal  rotor that turns due to passage of air upward through the  rotor. This air motion is created from forward motion of the  aircraft resulting from either a tractor or pusher configured  engine/propeller design.  [Figure 2-24] Upon completion of rigging, a thorough check should be made  of all attaching, securing, and pivot points. All bolts, nuts, and  rod ends should be properly secured and safetied as specified  in the manufacturers’ maintenance and service instructions. Configurations of Rotary-Wing Aircraft Autogyro Single Rotor Helicopter Figure 2-25.  Single rotor helicopter. Figure 2-24.  An autogyro. Figure 2-23.  A typical rigging protractor.  1.  The direction of movement of the main and tail rotor  blades is correct in relation to movement of the pilot’s  controls.  2.  The operation of interconnected control systems  (engine throttle and collective pitch) is properly  coordinated.  3.  The range of movement and neutral position of the  pilot’s controls are correct.  4.  The maximum and minimum pitch angles of the main  rotor blades are within specified limits. This includes  checking the fore-and-aft and lateral cyclic pitch and  collective pitch blade angles.  5.  The tracking of the main rotor blades is correct.  6.  In the case of multirotor aircraft, the rigging and  movement of the rotor blades are synchronized. 7.  When tabs are provided on main rotor blades, they  are correctly set.  8.  The neutral, maximum, and minimum pitch angles  and coning angles of the tail rotor blades are correct.  9.  When dual controls are provided, they function  correctly and in synchronization.  2-17 Main rotor rigging protractor 25° 20° 15° 10° 5° 0° CAUTION Make sure blade dampers are  positioned against auto-rotation inboard stops 15° 10° 5°