INSTRUCTIONS FOR USE SEE DIAGRAM:
A : Place of setting heading
B : Destination
C : A "fix" right of intended track.
EXAMPLE:The intended track was from A (Broken Hill)to B (Tibooburra) a distance of 156 n.m. A "fix" was obtained at c (Lake Buncannia) right of intended track.

METHOD: To determine alteration to heading to fly direct to B, distance flown A to C and distance to fly C to B.

1. Place the centre of the base-line over the "fix" C, with the base-line connected to the place of setting heading A.

2. Note the RADIAL intercepting B. In this case by interpolating the 10" RADIAL. Therefore, the alteration to the present heading to fly direct to B (Tibooburra) is 10" LEFT. Without moving the RULE from the above position:

3. The distance flown A to C, along the base-line, using the ARCS and interpolating is 74 n.m.

4. The distance to fly C to B, along the 10" RADIAL, again using the ARCS and interpolating is 82 n.m.

lf in the above example the "fix" had been LEFT of intended track then it would have been necessary to reverse the RULE and have the base-line to the LEFT.
TO DETERMINE TRACK ERROR: The track error is determined by placing the RULE with the centre of the base-line OVER THE Position oF SETTING HEADING and the base-line along intended track. The RADIAL which intercepts the "fix", interpolating if necessary, is the track error. In the above example the track error is 6'.

THE NAV-AID RULE has been constructed from a special synthetic material of such thickness and flexibility to allow it to be bent without permanent distortion or breakage.