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REGULATIONS

FLIGHT

Section 3251    ADF AND LOOP RECEIVERS

A. Navigation With Radio Loop Equipment (Cont'd)

3. Determining Correction Angle When Flying On-Course

a. Nose and Tail Bearings, QDMs, QDRs

(1) In using either tail or nose bearings in flight, it is necessary to determine the amount of correction required to stay on-course. Assuming that a pilot is flying from Syracuse to Smith Falls, attempting to maintain a magnetic course of 015(degrees). He starts out with a compass heading the same as his magnetic course disregarding any wind. If the air is calm or a direct tail wind or head wind is blowing, the heading and course will be the same. If the wind is blowing across the course, correction must be applied to remain on-course.

(2) The radio is tuned to Syracuse and the compass needle should bear on Syracuse 180(degrees) from the nose. The rotatable azimuth is now turned to the compass heading of 015(degrees). The compass needle should now point to Syracuse at the reciprocal of 15(degrees) or 195(degrees) the magnetic direction to Syracuse. This is assuming that the pilot is still on-course. Now assume that there is a strong northwest wind blowing. This will drift the aircraft to the southeast and the bearing on Syracuse will start shifting to the southwest. Assume that after 15 minutes of flight, Syracuse has a bearing of 200o instead of 195(degrees). This will mean the aircraft has drifted 5(degrees) to the right. The correct procedure then is to correct to the left twice the number of degrees of drift, terrain permitting in this case the aircraft should then be back on-course in approximately 15 minutes or the same number of minutes that it drifted off-course.

(3) To determine when he is back on-course, the pilot should reset his azimuth to his new compass-heading of 005(degrees). If the ADF is kept tuned to Syracuse, the on-course position is determined when the needle is again bearing on Syracuse at 195(degrees). He now reduces his correction one-half resulting in a new heading of 010(degrees). He resets the azimuth of the ADF to 010(degrees). If this is the proper heading, the needle will continue to bear 195(degrees) on Syracuse. If this is the wrong heading; that is, if he has corrected too much or too little, he will shortly drift off-course again, and by trial and error, he will find the proper amount of wind correction to remain on-course

2/1/47    Flight