indicator (RMI) with either one needle or dual needle. Fixed- card ADF (also known as the relative bearing indicator (RBI))  always indicates zero at the top of the instrument, with the  needle indicating the RB to the station.  Figure 9-3  indicates  an RB of 135°; if the MH is 045°, the MB to the station is  180°. (MH + RB = MB to the station.)  The movable-card ADF allows the pilot to rotate the aircraft’s  present heading to the top of the instrument so that the head  of the needle indicates MB to the station and the tail indicates  MB from the station.  Figure 9-4  indicates a heading of 045°,  MB to the station of 180°, and MB from the station of 360°. The RMI differs from the movable-card ADF in that it  automatically rotates the azimuth card (remotely controlled  by a gyrocompass) to represent aircraft heading. The RMI  has two needles, which can be used to indicate navigation  information from either the ADF or the VOR receiver. When  a needle is being driven by the ADF, the head of the needle  indicates the MB TO the station tuned on the ADF receiver.  The tail of the needle is the bearing FROM the station. When  a needle of the RMI is driven by a VOR receiver, the needle  indicates where the aircraft is radially with respect to the  VOR station. The needle points the bearing TO the station  as read on the azimuth card. The tail of the needle points to  the radial of the VOR the aircraft is currently on or crossing.  Figure 9-5  indicates a heading of 360°, the MB to the station  is 005°, and the MB from the station is 185°. The ADF can be used to plot your position, track inbound  and outbound, and intercept a bearing. These procedures  Function of ADF Figure9-5. Radio magnetic indicator (RMI). Because the aircraft’s  magnetic heading (MH) is automatically changed, the relative  bearing (RB), in this case 095 ° , indicates the magnetic bearing  (095 ° ) to the station (no wind conditions) and the MH that takes  you there. Figure 7-3. Relative bearing (RB) on a fixed-card indicator.  Figure 9-3.  Relative bearing (RB) on a fixed-card indicator. Note  that the card always indicates 360 °  or north. In this case, the RB  to the station is 135 °  to the right. If the aircraft were on a magnetic  heading of 360 ° , then the magnetic bearing (MB) would also be 135 ° . Figure 9-4. Relative bearing (RB) on a movable-card indicator. By  placing the aircraft’s magnetic heading (MH) of 045 °  under the  top index, the RB of 135 °  to the right is also the magnetic bearing  (no wind conditions), which takes you to the transmitting station.  9-4 33  30  24  21  15  12  6  3  S  W  E  N ADF needle  VOR needle  33  30  24  21  15  12  6  3  S  W  E  N  HDG 33  30  24  21  15  12  6  3  S  W  E  N