On September 24, 1993, at 0800 hours mountain standard time, a Cessna 172P, N98909, sustained a hard landing on runway 26L at Phoenix Sky Harbor Airport, Phoenix, Arizona. The pilot was completing a local visual flight rules personal flight. The airplane, operated by Sawyer Aviation, Phoenix, Arizona, sustained substantial damage. The certificated private pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The flight originated at Phoenix Sky Harbor Airport at an undetermined time; the flight departed Chandler Municipal Airport, Chandler, Arizona, at 0745 hours. The pilot submitted the required Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2. He stated in the report that after departing Sky Harbor Airport he flew to Chandler Airport to practice touch and go takeoffs and landings. The last landing at Chandler was "rough" and he elected to return to Sky Harbor Airport. After entering the Class B airspace the pilot began to feel ill and momentarily lost consciousness. After regaining consciousness the pilot was able to land the airplane, but sustained a hard landing in the process. The operator reported that subsequent medical tests on the pilot could not determine the reason for the pilot's loss of consciousness.