Alrite guys this formula has been derived from 1:60 rule. Note that the rule works reasonable well( to within 10%) for angles upto 20deg. If you tried to use the 1:60 rule with an angle of 45 deg, the estimation would not work.
Do not use the 1:60 rule for problems involving angles greater than 20deg.
Fortunately your glideslopes will be less than 20deg(for fixed wing a/c) and, hopefully, your track errors will not be greater than 20deg !
Given these conditions the formula can be applied:-
where he came up with 1.66 is
ROD= Glide Path Angle x 100 x G.S/60
ROD=1.667(100/60) x Glide path angle x G.S
For standard 3 deg glide path the formula is
ROD= G.S x 5
@KEITH WILLIMAS
Buddy I hope you knw the fact that this formula is applicable only till 20 deg so dont play with boy.
