N W S E 33 30 24 21 15 12 6 3 33 30 24 2I I5 I2 6 3 GS GS DC NOV HDG Direction indicator Flux valve or flux gate DG/Amplifier or slaved gyro 10-46 Figure 10-82.  Components used to prvide direction indication.  Figure 10-81.  A vertical magnetic direction indicator provides a  realistic reference of headings.  Remote Indicating Compass Remote Indicating Slaved Gyro Compass (Flux  Gate Compass) This alters the magnetic field produced by the coils of the  indicator in the cockpit, and a magnetic indication relatively  free from deviation is displayed. Many of these systems are  of the magnesyn type. An elaborate and very accurate method of direction  indication has been developed that combines the use of a  gyro, a magnetic compass, and a remote indicating system.  [Figure 10-82]  It is called the slaved gyro compass or flux  gate compass system. A study of the gyroscopic instruments  section of this chapter assists in understanding this device. A gyroscopic direction indicator is augmented by magnetic  direction information from a remotely located compass.  The type of compass used is called a flux valve or flux  gate compass. It consists of a very magnetically permeable  circular segmented core frame or spider. The earth’s magnetic  field flows through this iron core and varies its distribution  through segments of the core as the flux valve is rotated  via the movement of the aircraft. Pickup coil windings are  located on each of the core’s spider legs that are positioned  120° apart.  [Figure 10-83] The distribution of earth’s magnetic field flowing through  the legs is unique for every directional orientation of the  aircraft. A coil is placed in the center of the core and is  energized by AC current. As the AC flow passes through  zero while changing direction, the earth’s magnetic field  is allowed to flow through the core. Then, it is blocked or  gated as the magnetic field of the core current flow builds  to its peak again. The cycle is repeated at the frequency of  the AC supplied to the excitation coil. The result is repeated  flow and nonflow of the earth’s flux across the pickup coils.  Magnetic deviation is compensated for by swinging the  compass and adjusting compensating magnets in the  instrument housing. A better solution to deviation is to  remotely locate the magnetic compass in a wing tip or vertical  stabilizer where there is very little interference with the  earth’s magnetic field. By using a synchro remote indicating  system, the magnetic compass float assembly can act as the  rotor of the synchro system. As the float mechanism rotates  to align with magnetic north in the remotely located compass,  a varied electric current can be produced in the transmitter. 