are used to execute holding patterns and nonprecision  instrument approaches. The ADF needle points TO the station, regardless of aircraft  heading or position. The RB indicated is thus the angular  relationship between the aircraft heading and the station,  measured clockwise from the nose of the aircraft. Think of  the nose/tail and left/right needle indications, visualizing the  ADF dial in terms of the longitudinal axis of the aircraft.  When the needle points to 0°, the nose of the aircraft points  directly to the station; with the pointer on 210°, the station  is 30° to the left of the tail; with the pointer on 090°, the  station is off the right wingtip. The RB alone does not indicate  aircraft position. The RB must be related to aircraft heading  in order to determine direction to or from the station. When you are near the station, slight deviations from  the desired track result in large deflections of the needle.  Therefore, it is important to establish the correct drift  correction angle as soon as possible. Make small heading  corrections (not over 5°) as soon as the needle shows a  deviation from course, until it begins to rotate steadily toward  a wingtip position or shows erratic left/right oscillations. You  are abeam a station when the needle points 90° off your track.  Hold your last corrected heading constant and time station  passage when the needle shows either wingtip position or  settles at or near the 180° position. The time interval from  the first indications of station proximity to positive station  passage varies with altitude—a few seconds at low levels to  3 minutes at high altitude. The ADF may be used to “home” in on a station. Homing  is flying the aircraft on any heading required to keep the  needle pointing directly to the 0° RB position. To home in  on a station, tune the station, identify the Morse code signal,  and then turn the aircraft to bring the ADF azimuth needle to  the 0° RB position. Turns should be made using the heading  indicator. When the turn is complete, check the ADF needle  and make small corrections as necessary. Figure 9-6  illustrates homing starting from an initial MH of  050° and an RB of 310°, indicating a 50° left turn is needed  to produce an RB of zero. Turn left, rolling out at 50° minus  50° equals 360°. Small heading corrections are then made  to zero the ADF needle. If there is no wind, the aircraft homes to the station on a direct  track over the ground. With a crosswind, the aircraft follows  a circuitous path to the station on the downwind side of the  direct track to the station. NOTE: In  Figure 9-7 , for the aircraft closest to the station,  the WCA is 10° left and the RB is 10° right. If those values  do not change, the aircraft tracks directly to the station. If you  observe off-course deflection in the original direction, turn  again to the original interception heading. When the desired  course has been re-intercepted, turn 5° toward the inbound  course, proceeding inbound with a 15° drift correction. If the  initial 10° drift correction is excessive, as shown by needle  deflection away from the wind, turn to parallel the desired  course and let the wind drift you back on course. When the  needle is again zeroed, turn into the wind with a reduced  drift correction angle. For example, if your heading equals your course and the  needle points 10° left, turn 20° left, twice the initial RB.  [Figure 9-7] This is your intercept angle to capture the  RB. Hold this heading until the needle is deflected 20° in  the opposite direction. That is, the deflection of the needle  equals the interception angle (in this case 20°). The track has  been intercepted, and the aircraft remains on track as long  as the RB remains the same number of degrees as the wind  correction angle (WCA), the angle between the desired track  and the heading of the aircraft necessary to keep the aircraft  tracking over the desired track. Lead the interception to avoid  overshooting the track. Turn 10° toward the inbound course.  You are now inbound with a 10° left correction angle.  To track inbound, turn to the heading that produces a zero  RB. Maintain this heading until off-course drift is indicated  by displacement of the needle, which occurs if there is a  crosswind (needle moving left = wind from the left; needle  moving right = wind from the right). A rapid rate of bearing  change with a constant heading indicates either a strong  crosswind or close proximity to the station or both. When  there is a definite (2° to 5°) change in needle reading, turn in  the direction of needle deflection to intercept the initial MB.  The angle of interception must be greater than the number  of degrees of drift, otherwise the aircraft slowly drifts due to  the wind pushing the aircraft. If repeated often enough, the  track to the station appears circular and the distance greatly  increased as compared to a straight track. The intercept angle  depends on the rate of drift, the aircraft speed, and station  proximity. Initially, it is standard to double the RB when  turning toward your course. Tracking uses a heading that maintains the desired track  to or from the station regardless of crosswind conditions.  Interpretation of the heading indicator and needle is done to  maintain a constant MB to or from the station.  Tracking Orientation Station Passage Homing 9-5