Figure 3-1 VOR Navigation

CHAPTER THREE

T-6A INSTRUMENT NAVIGATION

030 Radial

360

090

270

180

210 Radial

Figure 3-1 VOR Navigation

The above example concerned EHSI indications with the aircraft at a fixed position. Let us now

consider the changes in EHSI indications produced by a moving aircraft.

NOTE

The following examples assume no wind conditions.

When flying either directly inbound to or outbound from a NAVAID, you will be maintaining a

constant course and staying on the same radial. In Figure 3-2, aircraft "A" is flying inbound to

the NAVAID with a heading of 135. The position of the aircraft is northwest of the NAVAID

on the 315 radial. It stays on the same radial despite the fact its geographical position changes

(moves closer to the station).

Aircraft "B" in Figure 3-2 is outbound from the NAVAID with a heading of 225. Again the

geographical position changes but the aircraft remains on the 225 radial.

If you fly a heading that does not take you directly inbound or outbound in relation to a

NAVAID, your position relative will change. In Figure 3-2, while maintaining a heading of

360, aircraft "C's" position changes from southeast of the NAVAID on the 135 radial to

northeast of the NAVAID on the 045 radial.

Figure 3-2 illustrates two important principles:

The tail of the needle always indicates which radial the aircraft is on.

2. Maintaining a constant heading if not flying directly to or from a NAVAID, will cause the

tail of the needle to rise and the head to fall (assuming no wind conditions).

3-2

FUNDAMENTALS OF INSTRUMENT NAVIGATION