NTSB Identification: CHI96FA135
HISTORY OF FLIGHT
On April 18, 1996, at 1430 central daylight time (cdt), a Piper J-3, N6510H, was destroyed during a collision with terrain and a post impact fire. Witnesses reported the airplane was on initial climb out after departing from a grass runway, when at approximately 250 feet the airplane banked sharply and descended into the terrain. The 14 CFR Part 91 flight was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. Both pilots on board were fatally injured. The airplane departed a private airport in Raymond, Nebraska, for the planned local flight.
The reported weather at Lincoln, Nebraska, at 1354 cdt was ceiling 6000 feet broken visibility greater than 10 miles, temperature 70 degrees, dew point 42 degrees, wind 310 degrees at 17 knots gusting to 24 knots, the altimeter was 29.64. The 1454 cdt weather observation at Lincoln, Nebraska was clear below 12000 feet, visibility greater than 10 miles, temperature 72, dew point 39, wind 280 degrees at 17 knots gusting to 24 knots, the altimeter was 29.64.
WRECKAGE AND IMPACT INFORMATION
The airplane wreckage path followed a magnetic heading of approximately 125 degrees. From the first ground scar mark to the location where the engine came to rest was measured at 29 feet four inches. A ground scar mark which was approximately normal to the direction of the wreckage path was measured at 33 feet 10 inches. The wing span of a standard J-3 Cub is listed at 35 feet two inches. The fuselage was buckled over approximately 90 degrees towards the right side of the airplane, between the rear seat and the tail. Both wings came to rest bottom side up. No evidence of fire was present on any of the plexiglass pieces found near the original impact location. The fuel gauge wire was found bent over, with approximately one half of the wire exposed.
All elevator, rudder and aileron control cables were continuous from the cockpit to their surfaces. All surfaces were attached and moved freely when checked by the investigator in charge (IIC) on April 19, 1996. The left aileron cable had a small amount of chaffing present were it exited the upper surface of the left wing, immediately in front of the aileron. Loose rib tapes were found in the area where the left aileron cables exited the left wing in front of the aileron.
All the flying wires which are used on the horizontal stabilizer were unbroken and attached. The jackscrew mount and rear attachment mounts for the horizontal were found attached and saftied. The trim cable for the horizontal was continuous from the jackscrew at the horizontal to the trim handle shaft in the cockpit. The horizontal stabilizer was set at a neutral position, which is consistent with the takeoff range.
All of the wing lift struts and brace struts were found attached except for one rodend which attached the lift strut to the fuselage. This rodend showed signs similar to a overload failure. Many of the leading edge ribs on both wings had been crushed and were flattened against the forward spar.
The gascalator bowl was saftied, and the drain valve was found at approximately its mid position. The screen inside the gascalator was not located. The fuel line from the gascalator to the carburetor was intact, but the internal rubber was melted. The mag switch was found in the both position, and the primer was found in, and locked. Both of the throttle controls were found in the full forward position. The throttle cable between the carburetor and the throttle lever was separated, with signs similar to a overload failure.
The air filter on the front of the carburetor air box appeared clean, except for sooting. The finger screen in the carburetor was clean except for sooting. The carburetor air box valve was found in the mid position. The carburetor had separated from its mount, and the exterior casting was fractured. The mixture control was found saftied, and the idle needle valve was installed. The throttle butterfly valve was found in the closed position. The carburetor was damaged and could not be flow checked on a test stand.
The fuel valve was found in the off position. The cockpit control lever for the fuel valve can be seen in the background when the carburetor was photographed. This photograph was taken before the engine was separated from the wreckage. During the documentation after moving the wreckage the fuel control lever measured approximately 1 and one eighth inches from the end of the installation nut to the center of the handle. No fuel samples could be taken from the accident airplane.
Both blades on the propeller were bent with a trace of chordwise scratches present. Neither propeller blade showed any signs of torsional bending.
MEDICAL AND PATHOLOGICAL TESTING
On April 19, 1996, an autopsy was performed on both pilots in Lancaster County. Toxicological testing performed on both pilots by the Federal Aviation Administration in Oklahoma City, Oklahoma, was negative for all tests conducted.
TESTS AND RESEARCH
The engine was placed in a shipping container and sent to the manufacturer's overhaul facilities on April 20, 1996. No abnormalities were noted with the engine during disassembly at the manufacturer's facilities on June 3, 1996. The complete engine disassembly report is included as a supplement to this report.
Both magnetos were damaged due to fire. Neither magneto could be benched checked for proper operation.
The aircraft owner was called by the investigator IIC on April 23, 1996 to discuss the rigging of the fuel valve cable. The owner stated that the fuel valve handle was always left in the on position, and not shut off after every flight. The owner stated that the distance from the mounting nut to the center of the actuation shaft was rigged at approximately one half inch when the fuel valve was in the on position. The owner also stated that it required a firm pull to actuate the fuel control cable.
On August 8, 1996 the IIC tested airplane N98506, a similar airplane as the accident aircraft. The airplane's fuel tank was approximately one half full during the testing. The fuel valve handle had approximately two inches of travel from the on to the off position. With the fuel valve set at approximately one inch aft of the on position the aircraft's engine operated normally at the maximum power setting. With the fuel valve handle at one and one quarter inches aft of the on position the aircraft's engine operated approximately 20 seconds at the maximum power setting, then the engine had a total loss of power. With the fuel valve at one and one eighth inches aft of the on position, the aircraft's engine operated approximately 30 seconds at the maximum power setting, then the engine had a total loss of power.
Five different witnesses gave statements to the Lancaster County Sheriffs department. All witnesses reported that the airplane reached an altitude of approximately 250 feet before it departed controlled flight and descend into the terrain. Because of the other differences between their statements, the dictated police report is included with this reported.