Navigation

To return to the desired radial, the aircraft heading must be maintain the course. If the aircraft drifts, fly a heading altered to the right. As the aircraft returns to the desired track, to re-intercept the course then apply a correction to the deviation needle slowly returns to center. When centered, compensate for wind drift. the aircraft is on the desired radial and a left turn must be • If minor needle fluctuations occur, avoid changing made toward, but not to the original heading of 350° because headings immediately. Wait a moment to see if the a wind drift correction must be established. The amount of needle recenters; if it does not, then you must correctly correction depends upon the strength of the wind. If the wind recenter the course to the needle. velocity is unknown, a trial-and-error method can be used • When flying “TO” a station, always fly the selected to find the correct heading. Assume, for this example, a 10° course with a “TO” indication. When flying “FROM” a correction for a heading of 360° is maintained. station, always fly the selected course with a “FROM” indication. If this is not done, the action of the course While maintaining a heading of 360°, assume that the course deviation needle is reversed. To further explain this deviation begins to move to the left. This means that the wind reverse action, if the aircraft is flown toward a station correction of 10° is too great and the aircraft is flying to the with a “FROM” indication or away from a station right of course. A slight turn to the left should be made to with a “TO” indication, the course deviation needle permit the aircraft to return to the desired radial. indicates in a direction opposite to that which it should indicate. For example, if the aircraft drifts to the right When the deviation needle centers, a small wind drift of a radial being flown, the needle moves to the right correction of 5° or a heading correction of 355° should be or points away from the radial. If the aircraft drifts to flown. If this correction is adequate, the aircraft remains the left of the radial being flown, the needle moves on the radial. If not, small variations in heading should be left or in the direction opposite of the radial. made to keep the needle centered and consequently keep the aircraft on the radial. • When navigating using the VOR, it is important to fly headings that maintain or re-intercept the course. As the VOR station is passed, the course deviation needle Just turning toward the needle will cause overshooting fluctuates, then settles down, and the “TO” indication the radial and flying an S turn to the left and right of changes to “FROM.” If the aircraft passes to one side of the course. station, the needle deflects in the direction of the station as the indicator changes to “FROM.” Time and Distance Check From a Station Using a RMI Generally, the same techniques apply when tracking To compute time and distance from a station, first turn the outbound as those used for tracking inbound. If the intent is aircraft to place the RMI bearing pointer on the nearest 90° to fly over the station and track outbound on the reciprocal of index. Note the time and maintain the heading. When the the inbound radial, the course selector should not be changed. RMI bearing pointer has moved 10°, note the elapsed time Corrections are made in the same manner to keep the needle in seconds and apply the formulas in the following example centered. The only difference is that the omnidirectional to determine the approximate time and distance from a given range indicator indicates “FROM.” station. [Figure 16-33] If tracking outbound on a course other than the reciprocal of The time from station may also be calculated by using a short the inbound radial, this new course or radial must be set in method based on the above formula, if a 10° bearing change the course selector and a turn made to intercept this course. is flown. If the elapsed time for the bearing change is noted After this course is reached, tracking procedures are the same as previously discussed. Time-Distance Check Example Tips on Using the VOR Time in seconds between bearings = Minutes to station • Positively identify the station by its code or voice Degrees of bearing change identification. For example, if 2 minutes (120 seconds) is required to fly a • Remember that VOR signals are “line-of-sight.” A bearing change of 10 degrees, the aircraft is— weak signal or no signal at all is received if the aircraft 120 is too low or too far from the station. = 12 minutes to the station 10 • When navigating to a station, determine the inbound radial and use this radial. Fly a heading that will Figure 16-33. Time-distance check example. 16-26