Skin Bulkhead Frame Stringer Longeron Skin Spars Rib Stringer Figure 1-48.  Vertical stabilizer.  Figure 1-46.  The fuselage terminates at the tail cone with similar  but more lightweight construction.  Figure 1-47.  Components of a typical empennage. Elevator Rudder Trim tabs Vertical stabilizer Horizontal stabilizer The other components of the typical empennage are of  heavier construction than the tail cone. These members  include fixed surfaces that help stabilize the aircraft and  movable surfaces that help to direct an aircraft during flight.  The fixed surfaces are the horizontal stabilizer and vertical  stabilizer. The movable surfaces are usually a rudder located  at the aft edge of the vertical stabilizer and an elevator located  at the aft edge the horizontal stabilizer.  [Figure 1-47] The structure of the stabilizers is very similar to that which  is used in wing construction.  Figure 1-48  shows a typical  vertical stabilizer. Notice the use of spars, ribs, stringers,  and skin like those found in a wing. They perform the  same functions shaping and supporting the stabilizer and  transferring stresses. Bending, torsion, and shear created  by air loads in flight pass from one structural member to another. Each member absorbs some of the stress and passes  the remainder on to the others. Ultimately, the spar transmits  any overloads to the fuselage. A horizontal stabilizer is built  the same way . The rudder and elevator are flight control surfaces that are  also part of the empennage discussed in the next section of  this chapter. The directional control of a fixed-wing aircraft takes place  around the lateral, longitudinal, and vertical axes by means  of flight control surfaces designed to create movement about  these axes. These control devices are hinged or movable  surfaces through which the attitude of an aircraft is controlled  during takeoff, flight, and landing. They are usually divided  into two major groups: 1) primary or main flight control  surfaces and 2) secondary or auxiliary control surfaces. The primary flight control surfaces on a fixed-wing aircraft  include: ailerons, elevators, and the rudder. The ailerons are  attached to the trailing edge of both wings and when moved,  rotate the aircraft around the longitudinal axis. The elevator  is attached to the trailing edge of the horizontal stabilizer.  When it is moved, it alters aircraft pitch, which is the attitude  about the horizontal or lateral axis. The rudder is hinged to  the trailing edge of the vertical stabilizer. When the rudder  changes position, the aircraft rotates about the vertical axis  (yaw).  Figure 1-49  shows the primary flight controls of a  light aircraft and the movement they create relative to the  three axes of flight. Primary Flight Control Surfaces Flight Control Surfaces 1-24