Originally Posted by 5-in-50
In practice, the accuracy and errors of the NDB, ADF and turbulence will make the theory imeasurable.
Bringing wind into the situation simply means that the whole head falling and tail rising rule is offset by the drift angle. Still, you'll never achieve a true 'needle on the tail' condition (+-drift angle) unless you have either flown over the station or changed from a straight path to conduct an intercept
Originally Posted by Oktas8
In general, the head of the needle will tend to move from top to bottom. In general, you will not know precisely whether you're on track or not - but you should generally have a fair idea of a heading which will reduce the track error, such as it is.
I second the remark above, that drift angle is a fixed correction to apply. With wind, the tail will not end up at twelve o'clock.
And that's where the debate began . . . Because in the SIM it's possible to measure the theory pretty accurately, as wind is constant, there is no turbulence and you have almost perfect "flying" conditions.
On an outbound track of 145, on a heading of 165, offsetting 20 degrees of drift, my instructor says: "You'll notice the needle (which at this stage is 20 degrees right) will tend to fall towards the tail (swing towards 180) the further outbound you are".
My question was: "Why? The needle should remain in the same position."
On a constant track, on a constant heading, with no change in wind, the angle should remain the same no matter how far out you are.
But I accept it's not a perfect world, and so obviously what he was trying to explain was that the further out you are, the less the needle deflects for each mile off track.
Thanks for all the explanations, but I still think the theory is correct - if not in practice.