flight plan question... IFR

[fulanito_uk]

Hi all, i'm stuck...
I am flying this plan

PAJN

HNS (245.0) (heading 305)
HNS 30 (heading 337)
COALE (heading 344)

CYXY

Ok so i get it take off fly a heading of 305 on HNS (245 in the ADF) follow the arrow on the indicater, when the arrow swings down means i've pasted over HNS, time to go on HNS 30 (change heading to 337) right??

How do i know when I get to COALE do i just have to work it out with distance from HNS 30?

Thanks for you help!!

[Strategic Retreat]

How do i know when I get to COALE do i just have to work it out with distance from HNS 30?

In short, yes. If the fix is does not correspond to a navaid, then you must use the DME from the last VOR to know when you are on the given fix.

Or sometimes the fix is a bisection of two different radials of two different VORs, in which case you don't strictly need DME, but an IFR panel capable to manage two different VOR signals at the same time (or need to fiddle with the sole one you got, I guess), to know when you're on the fix.

Of course, if you got GPS it's even simpler to know when you're on the fix, but if you want to fly old school, when GPS stood for Going to a Party this Saturday... it's only VOR and DME for you.

[fulanito_uk]

thanks for the reply.. problem is HNS 30 is not a VOR....

Thanks

[Strategic Retreat]

thanks for the reply.. problem is HNS 30 is not a VOR...

Not a problem at all. For that there's a clock or better a chronometer beside the airspeed indicator in every IFR capable cockpit ever since the 20ies. Given a certain speed your plane is moving at (ground speed), you can calculate the time you need to reach the distance between HNS and the fix COALE with good precision.

The actual formula is: S / V == T * 60

Where S is Space in nm, V is Velocity in knots ground speed, and T is the resulting time factor that must be multiplied to the amount of minutes in a hour (60).

Simple example: Given your ground speed is 100knots and the hypothetical space between HNS and COALE is 30nm the formula would look like this:

30 / 100 == .3 * 60 == 18 minutes of flight

Or at least this is the formula I've always used in this kind of occasions and it has yet to fail me.

[fulanito_uk]

Wow great will give it a try, let you know my results a little later!

Thanks for taking the time!

[fulanito_uk]

Here is the result of the "COALE" intercept (13.48 mintues from HNS 30) not perfect but practice makes perfect

[Strategic Retreat]

Practice makes perverts perfect.

The technique is hardly new and dates back to the first non-visual flights of the 20ies of the 20th century, and of course you MUST take into account not only the speed and distance, but the drift due to winds aloft as well (at least in real life). But for that I have no formula. Always corrected empirically.

This is how instrumental flight was born, actually.