On August 7, 1994, about 0530 eastern daylight time, an unmanned Cessna 152, N67334, registered to Leaseair Clearwater Inc., operating as a 14 CFR Part 91 personal flight, collided with the pilot-in-command and a parked airplane on the St. Petersburg-Clearwater International Airport. The airplanes sustained minor damage. The private pilot received a serious injury. Visual meteorological conditions prevailed and no flight plan was filed. The pilot stated he started the engine and noticed he had not removed the left wing tie-down during the preflight inspection. He retarded the throttle to the idle position, exited the airplane, walked around to the front of the leading edge of the left wing, removed the tie-down, turned to the left, and walked into the propeller. The Pilot's Operating Handbook for the Cessna 152, Section 4, Normal Procedures, Preflight Inspection, states in the checklist, wing tie-down-disconnect. It further states in the before start engine checklist, brakes-test and set.