21-7. Divide the ground speed conversion number into D (the DZ length minus the 200-meter buffer for all drops involving personnel); this determines T. Any fractional answer is rounded down to the next whole number.21-8. For example, how many jumper from a CH-47 (drop speed of 90 knots) can land on a 750 meter DZ each pass? To figure it out, use the following:T = Number of jumper.D = DZ length is 750 meters (given).R = Airspeed is 46 meters per second (90 knots .51 = 45.9; round up to 46).Solution: T = D/R (D divided by R).D/R = 750 meters - 200 meters = 550 divided by 46 meters per second = 11.9 seconds.T = 11 seconds (round down).Eleven seconds over DZ by one jumper per second + 1 jumper (the first jumper exiting the aircraft does not affect the number of seconds spent over the DZ) = 12 jumpers. Thus, 12 jumpers per pass can land on the 750 meter DZ.