We don't know . . .
-- the speed of the airplane at the moment he jumped
-- the altitude of the airplane at the moment he jumped
-- the speed or direction of the winds at every altitude all the way down
-- the position he was in during the 4 seconds of "free"-fall
-- the skydiver's weight
-- the drag of his parashoot
Otherwise, this sounds like a fun problem to work on.
I can tell you this:
The vertical component of the skydiver's total fall is equal to
(the airplane's elevation above sea level at the moment he jumps)
minus
(the elevation above sea level of the ground upon which he lands).
