User Guide

134
135
Flight Instruction
Flight Instruction
HOMING AND TRACKING:
The easiest way to get to an NDB is simply to “home” on it:
just turn the airplane until the needle points straight ahead, and
keep it there.
Unfortunately, this won’t give you a straight track across the
ground. Instead, the wind will push you one way or the other. As
you keep turning to keep the station straight ahead, your heading
will change. If you started at any significant distance from the sta-
tion, you’ll invariably end up approaching the station directly into
the wind.
Instead, determine the
magnetic bearing to the station
by adding the relative bearing to
your compass heading. (If the
result exceeds 360 degrees, just
subtract 360 - for example, if
you’re heading 345 and the rel-
ative bearing is 030 for a total of
375, subtract 360 to get the cor-
rect magnetic bearing of 015.) Now turn to the magnetic bearing;
the needle should initially point straight ahead.
Next, hold that heading, and watch the needle. Unless
you’re very lucky, it’ll gradually start to drift to one side or the
other, indicating that you’re being blown off course.
If you were to just turn
until you were pointed right at
the station again, you’d merely
be homing again. Instead, turn
until the needle is as far on the
opposite side of the zero index
as it has drifted. This should
gradually bring you back to the
correct course, at which point the needle will have moved even
farther to the opposite side.
Now take out about half the correction. Continue to fly this
new heading, making further refinements as necessary.
DON’T LIKE ARITHMETIC?
The constant mental calculation of relative and magnetic
bearings has been the bane of ADF flyers for years, but there are
some ways around it.
Perhaps the simplest is to just visualize the ADF needle
superimposed on your directional gyro (DG). If it’s pointing 45
degrees right, for example, just look at your DG and note the num-
ber under the 45-degree “tick mark;” that’s the magnetic bearing
to the station.
A small step up in complexity are more modern ADF indi-
cators with a movable, rather than fixed, compass rose. Just twid-
dle the little adjusting knob to set your current magnetic heading
at the top of the instrument, and read the magnetic bearing to the
station directly from the needle. (You can also read your radial
from the station under the tail of the needle.)