how to solve? 1 [Archive]

ARGPILOT

5th Jul 2007, 17:05

airplane desceding a 12% slope while maintaining a GS of 540.

What is the rate of descend aprox?

thanks

Capt. Slow

5th Jul 2007, 18:17

D'oh, very simple, but forgotten how! Isnt it:

G/S(ft per min)*(Glide slope in degrees/60)=Rate of Descent

I keep gettin 6201 ft/min ROD on a 6.8deg slope, which seems unusaully high...

DBate

5th Jul 2007, 18:32

For the required rate of descent multiply the descent angle by the NM/minute times 100.

Taking your example...

540kt = 9NM/min
12° x 900 = 10800'/min.

But... who would fly a 12° angle :confused:

Capt. Slow

5th Jul 2007, 18:38

Wasnt it a 12% gradient and not 12 degree? a little steep!

ray cosmic

5th Jul 2007, 18:45

Space shuttle?

DBate

5th Jul 2007, 19:28

Oh, sorry for that! You are absolutely right - it is gradient, not a slope...

In that case, to find the rate required, multiply the gradient by the GS (or rather TAS).

12% x 540 = 6480'/min.

Regards

Capt. Slow

5th Jul 2007, 19:32

So call it an even 6300' ;) Well your method seems a lot simpler than mine, might adopt that for the future...