On September 20, 1993, at 0904 hours Pacific daylight time, a Christen Industries, Inc., Pitts S-2B, N88EW, ground looped during the landing roll-out on runway 25 at Hawthorne Municipal Airport, Hawthorne, California. The pilots were conducting a local visual flight rules instructional flight. The airplane, operated by the flight instructor, sustained substantial damage. Neither the certificated airline transport pilot/flight instructor (CFI) nor the certificated private pilot/dual student was injured. Visual meteorological conditions prevailed. The flight originated at Hawthorne Municipal Airport at 0840 hours. The CFI reported in the Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2, and in a subsequent telephone interview, that the he was providing dual instruction so that the private pilot could "check-out" in conventional gear (tailwheel) airplanes. The dual student landed normally on the second landing. During the landing roll-out, the airplane began to drift to the right. The CFI instructed the dual student to apply left rudder to arrest the drift; however, the dual student applied "full left" rudder and the airplane swerved violently to the left. The CFI could not arrest the turn and the airplane "ground looped." The dual student reported in the Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2, that during the landing roll-out the airplane began to drift slowly to the left. The dual student stated he applied full right rudder while the instructor also applied full right rudder and right brake. The airplane continued to turn to the left and exited the runway.