Aircraft Accident/Incident Report

Pahokee, Florida 33476
Thursday, April 3, 2003 7:15 EST

The CFI reported that shortly before the accident, they were each taking turns practicing, "...agricultural turns a few hundred feet over fields...." He had completed a few of the turns and the rear seat occupant took the controls to take his turn at practicing the turns. The rear seat occupant took over the flight controls from him and had completed a few of the turns. During the middle of one of the turns being flown by the rear seat occupant, he (CFI) adding power abruptly and the engine hesitated/coughed. He had full aft elevator control input and was out of elevator control travel. The airplane then impacted the ground. He is aware that the carburetor does not have an accelerator pump, and did not perceive a preimpact flight control malfunction. Additionally, he did not feel that the engine hesitation caused the airplane accident. The passenger advised the owner post accident that while flying at approximately 150 feet above ground level, at an adequate airspeed (60-70 mph), the left wing dropped. The passenger further reported that the CFI said, "my aircraft", and the next thing the passenger knew, the aircraft was on the ground. There were no known witnesses to the accident. Examination of the airplane by an FAA inspector revealed evidence the airplane touched down in the field first with the left main landing gear; a piece of landing gear tubing remained in the initial ground scar location. The airplane slid approximately 20 feet and came to rest upright. The fuselage was broken aft of the aft seat; the empennage was displaced to the left. The engine and engine cowling were displaced to the right. Fuel was noted in the fuselage tank, and in the carburetor bowl; the carburetor was fractured near the flange and remained secured by the throttle control cable. Examination of the airplane following recovery by the NTSB revealed no evidence of preimpact failure or malfunction of the flight controls for roll, pitch, or yaw. Impact damage was noted to the left wingtip. The ignition switch operationally checked satisfactory. Examination of the engine revealed crankshaft, camshaft, and valve train continuity. Suction and compression was noted in all cylinders. The magnetos sparked at all spark plugs through the ignition leads during hand rotation of the engine. Bench testing of the retained carburetor revealed fuel leaked from the main metering nozzle when 6 psi was applied to the inlet. Disassembly of the carburetor revealed the float was properly installed; a plastic needle valve was noted to be installed. A slight amount of dirt was noted in the throttle bowl area. The carburetor was not equipped with a mixture control or accelerator pump.

The instructor's inadequate in-flight decision and his delay in taking remedial actions. Also causal was the student pilot's failure to maintain airspeed which resulted in a stall. Low altitude flight is a contributing factor.