Formula for distance to loc/finals?

[wandrinabout]

I'm trying to remember the 1 in 60 formula to work out how many track miles you have to run to finals or loc intercept, based on degrees off final and distance.

Being lazy by asking I know, but thanks anyway.....

[Notso Fantastic]

I can't work out what you mean but it doesn't sound a sensible calculation to try and make in your head when you are trying to intercept an ILS. The 1 in 60 (ie 1 degree) rule leads to an approximation of a 3 degree glideslope being 3000' AAL at 10 miles, 4500' at 15 miles etc. Otherwise who cares what other distances are involved- concentrate on flying the aeroplane right! What you want to work out is not possible.

[Gerund]

Wandrinabout

Why not be really lazy

If you are receiving radar vectors onto the ILS, just ask approach and they will tell you! After all they are the only ones who really know and they will be happy to tell you - so that you can update your descent profile to be at the right altitude for the intercept.

[Miserlou]

If I remember correctly the 60 rule version only works if you are close to perpendicular the final course.

[compressor stall]

This rule of thumb might help...

If you're flying a DME ARC:

Every 60 degrees is about the same as the inbound leg (or ARC DME) (less than half a mile difference for a 10DME Arc)

OR even easier:

For 10 DME Arc, every 6 degrees is a mile
For 12 DME Arc, every 5 degrees is a mile
For 15 DME Arc, every 4 degrees is a mile.

Simple math will show that these figures are close enough to be exact for thier intended purpose.

I am sure you are not too lazy to work out the pattern in the above....

[wandrinabout]

Cheers for the responses all

Maybe I should have given a bit more info, so as not to sound so vague.

My question isn't really a big deal on line, as some of you point out, as we have the toys; radar, GPS, GNSS, FMC etc.
I was asking more in the context of a sim ride, whilst on raw data or the likes - has happened to me a few times where I would have liked to have known how far I had to go, esp on a non prec.

I know that sine of the angle off x the distance works for a right angle intercept, but 'fraid I can only do a rough guestimation when in the above scenario as it doesn't take much to overcook my grey matter.

So hence was wondering if the 1 in 60 method was easier in respect of a quick mental calc whilst in stress mode.

miserlou if the calc only works for perpendicular intercept, thats fine for me....

compressor I like it, cheers

Thanks

[Notso Fantastic]

You want to work out sine calculations, in your head, whilst trying to fly and intercept to an ILS? Luvvaduk! Do what everybody else does- just get the aeroplane in the right configuration in near enough the right place and concentrate on flying it right! Leave the sliderule calculations to someone else! You just get a 'feel' when to do the right thing at (almost) the right time. Don't do sums in your head!

[fireflybob]

The bearing to the LOM gives an indirect indication as to how many track miles you have to run, especially when added to other datawhich may be available. Can't give you any hard and fast rules but the bearing to the LOM is an indication which is frequently underused.

[wandrinabout]

Notso

Sine calc's notso bad, I use the clockface
ie: sine 45 - 3/4
30 - 1/2
20 - 1/3
15 - 1/4
10 - 1/6 (close enough)

But you are right, of course fly the a/c first, but.........