glide slope

[nam]

How do you guys calculate the glide slope angel? Like when you 3 degrees or whatever. If I am going 150, what should my  FPM be?

[OTTOL]

Take your groundspeed, add a zero, and divide by two.
IE: 120 KTS------ 120 & 0/1200  1200/2=600   600FPM would be your AVERAGE descent rate for an approach at 120KTS. Remember, this is a BASE figure, and is dependent on GROUNDSPEED, not AIRSPEED.

Like when you 3 degrees or whatever

Three degrees is standard for an ILS. If the angle is other than standard, it is usually noted on the approach plate. The difference in descent rate between a 3 degree and 3.5 degree glideslope, will be minimal. Use the formula given, and vary the rate as necessary. It should be NO more than 100 FPM +/- , from the base number.

[RitterKreuz]

there are two fiarly accurate methods to determine your rate of descent on a 3 degree glide slope. Both are based on groundspeed, not indicated airspeed so you may have to look at the GPS to see what the Groundspeed is (Assuming there is absolutely no wind groundspeed and indicated airspeed will be pretty much the same).

method 1.
Take the ground speed you are achieving and multiply it times 5

in your case, 150 kts X 5 = 750 fpm

method 2.
Take the ground speed you are achieving and add a zero then devide by 2.

in your case, 150 (add a zero to the end) = 1500

1500 devided by 2 = 750 feet per minute

[RitterKreuz]

Well OTTOL! good work haha if it werent for my wife calling and pestering me about my illness i might have beat you to the punch! haha

i guess you provide the formula and ill save him the math ;-)

[OTTOL]

LOL............I've started to reply to a post before, and between the wife, the child, the dog, the cats, work calling, and burning the toast, it sometimes takes an hour to type three lines!!!!
As long as the question is answered.................then MISSION ACCOMPLISHED!  ;)

[nam]

Thanks guys

[Fredgirardo]

Hi Nam,

     It is more about speed than degree. Try to controle your speed with the yoke and control the descent rate (FPM) with the throttle. The speed is directed link with the attack angle.

                                     Cheers