On February 16, 2005, about 1000 eastern standard time, an Interplane SRO Skyboy experimental airplane, N942WW, operated as a Title 14 CFR Part 91 instructional flight, crashed while taking off at Zephyrhills, Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The flight instructor and student received serious injuries, and the aircraft was destroyed. The flight was originating at the time of the accident. The instructor did not submit a Pilot/Operator Accident/Incident report form to the NTSB. He stated that he is an Aero Sports certified ultralight flight instructor and he and his student were on an instructional flight when the accident occurred. He stated that they were taking off from runway 22 and the aircraft had climbed to about 50 feet altitude, when the flight controls stuck to the left and the airplane descended in a spiral, impacting the ground. He stated that the engine was been developing full power, and he could not apply any flight control input to correct the descending spiral. He said he remembered checking to see if the student had been on the controls while he was trying to arrest the descent, but the student was not on the controls, nor had he stalled the aircraft during the climb. According to the pilot the airplane was a "pusher" with the engine and propeller in the rear. When the airplane impacted the ground the fuselage became mangled from the nose all the way aft to the engine. An FAA inspector who responded to the accident site said that witnesses told him they saw the airplane descend in a left spiral and that after impacting the ground the engine continued operating and had to be secured in order to remove the occupants. According to the inspector the airplane was destroyed and the extent of the damage precluded him from determining if there were any evidence of flight control related anomalies.