Okey dokey. The easy ballpark figures I use to maintain a 3* GS maneuvering on the initial or intermediate approach phases are as follows;
At average approach speed (140kts) and 800fpm ROD plan on loosing 300-350 feet per NM if you maintain a 3*GS.
Determine height to loose on the arc, ie if initial approach fix is at the beginning of the arc at 5000msl and the final aproach fix is at 2000msl then TOD will be 10 track miles prior to the FAF assuming speed approx 150ish and ROD 800-1000fpm.
Still a variation of the 1 in 3 or 3 in 1 rule so easy to remember.
Based on junior school maths (my comfort level) but if you have to come up with a plan in a flash it works fine for this too!
Re read thread, looks as though I`m prattling on about the wrong thing. Thus prior to applying the 1 in 3 rule you need to apply the 1 in 60 rule. 1* displacement at 60nm=1nm.
0n a 15nm arc each degree equals 1/4 mile so 40*of arc is 10nm straight line from start to finish so add 30% for the arc (that 3 again) gives approx 13nm. That should keep you on the consevtive side with a level off prior to the FAF. Again the 1 in 60
plus 30% is ballpark but relatively easy mental maths.
Last edited by flite idol; 9th June 2004 at 13:58.