A Chicago man described Monday how he was struck in the leg by a bullet that came through the bottom of a small plane he was flying over Cedar Lake, Ind.

Stephen J. Broussard, 43, a self-employed attorney from Hyde Park, said he was flying a single-engine Piper Warrior at about 1:30 p.m. Sunday out of Gary Regional Airport with his flight instructor, Jeff Riley, when Broussard heard a noise and felt a pain on the bottom of his right thigh near the buttocks. He was flying at about 2,400 feet at the time, he told Indiana State Police.

''Immediately, I started checking the plane . . .,'' he said.

Broussard described the pain in his thigh ''like somebody had popped me with a wet towel.''

Riley speculated that perhaps a spring had broken in Broussard`s seat. However, after they landed a few minutes later at the Gary airport, Broussard said he saw a hole in his seat and a hole in his pants along with some blood and told Riley, ''I`ve been shot.''

The two men later found a hole in the bottom of the seat corresponding to the one in the top, a hole in the outside fuselage of the plane, and a hole in the floor of the plane, Broussard said, but they have not yet found the bullet.

Indiana State Police flew over the area with Riley, Broussard said, and are investigating. Broussard was treated at a hospital.