If I'm not mistaken, he was flying for the flat spin sequence in Top Gun. With a camera mounted on the tail of his airplane. Flat spin +aft CG enhanced by movie cameera on the tail.. basically he ended up in an airplane that flat spun exceptionally well, but it didn't want to recover a bit.

from http://www.check-six.com/lib/Famous_Missing/Scholl.htm: After successfully completing an upward spin in his aircraft, Scholl attempted an inverted flat spin. While descending rapidly in the spin, and at an altitude of 3,000 feet, he uttered, "I've got a problem." Shortly later,, at an altitude of 1,500 feet, he spoke his last known words... "I've really got a problem." Rescue planes recovered only some floating debris, and it was speculated that the aircraft sank to a depth of over 900 feet.

The exact cause of the fatal crash remains unknown, as neither the plane, nor Scholl's body, was ever recovered.