LAX99LA233

The pilot was flying about 6,500 feet agl when his engine dropped to 500 rpm. He manipulated the primer and the engine rpm began to fluctuate. The engine then quit. The pilot performed a forced landing in an open field and collided with ground obstructions. The aircraft was examined following the accident. The fuel tanks were about half full. The carburetor was examined further. When the carburetor was flow tested, fuel was seen dripping from the discharge nozzle after the fuel was turned on, indicating that the float needle was not seating properly, which could cause the engine to run excessively rich. The float needle was not properly torqued in the bowl assembly. Further, small pieces of brass appeared to have exfoliated around the top of the needle-seating surface. The needle appeared to have been altered from its original configuration. No other mechanical problems were noted with the aircraft or engine.

On June 29, 1999, at 1257 hours Pacific daylight time, an Ercoupe E, N3640H, experienced a loss of power and force landed in an open field in Winnemucca, Nevada. The aircraft, owned and operated by the pilot, sustained substantial damage. The private pilot was not injured. The personal cross-country flight, conducted under the provisions of 14 CFR Part 91, originated at the Jackpot, Nevada, airport, about 1100, and was destined for Winnemucca with a final destination of Reno, Nevada. Visual meteorological conditions prevailed and no flight plan was filed.

The pilot reported that he began the accident leg of the flight with full fuel tanks, a total of 24 gallons, for the 178-mile trip. He stated that he was flying with a group of other airplanes. About 13 miles from Winnemucca at 6,500 feet agl, the engine began to run rough and the rpm decreased to 500 rpm. He applied carburetor heat but the engine did not respond. The pilot reported that after checking the fuel gauges, he believed that he was out of fuel. He stated that he manipulated the primer in an attempt to keep the engine running until he could find a place to land. He reported that the rpm began to fluctuate, then the engine quit completely. The pilot radioed the other aircraft and advised the pilots that he was going to land. He made an emergency landing to a dirt road and exited the cockpit uninjured.

A Humboldt County Sheriff's Deputy witnessed the accident. He reported that he observed the airplane flying about 1,500 feet agl near a local high school. He stated that he could hear the engine surging and he noted that the airplane was rocking back and forth and appeared "unstable." The airplane suddenly descended in a sharp left turn. The deputy drove toward the area and arranged for medical personnel to respond. He reported that the airplane continued to rock from side to side as it descended toward the dirt road. The deputy stated that the airplane landed on the road, then bounced and continued forward about 100 feet. Both wings struck the sagebrush and the airplane swerved. The right main gear collapsed the right wing was substantially damaged. The aircraft came to a stop and tilted forward on the nose.

The deputy looked in the fuel tanks and reported that both side tanks were about half full and the center header tank contained its full capacity of 5 gallons.

A Federal Aviation Administration inspector from the Reno Flight Standards District Office examined the aircraft and powerplant following recovery. He reported that the only discrepancy he noted was that the fuel screen was clean but contained no fuel.

A disassembly and inspection of the carburetor was performed at Precision Airmotive in the presence of Safety Board investigators. A copy of that report is appended to this file.

The external condition of the carburetor revealed no damage. Throttle and mixture controls rotated freely. There was no damage to the throttle body or bowl assembly. The safety wire was missing from the mixture control and fuel screen plug. Additionally, a plug was missing from the throttle body bore area and the carburetor screen plug was loose.

The fully assembled carburetor was flow tested at 0.5 psi inlet pressure. Fuel was seen dripping from the discharge nozzle approximately 30 seconds after the fuel was turned on. The Precision representative reported that this indicated that the float needle valve was not seating properly.

The carburetor throttle body assembly was removed from the bowl and flow tested to determine float level. The flow test confirmed that the float needle valve was not seating. The Precision representative reported that he was not able to determine the float level because of the leaking float needle valve.

A tear down inspection of the carburetor was performed. The inspection revealed that the inlet screen was clean. No contamination was found in the idle or nozzle passages. All gaskets were present and in fair condition. The Precision representative noted that a liberal amount of gasket sealer had been used on the throttle body to bowl gasket. The venturi was not damaged. No defects were noted during the visual inspection and leak test of the float. According to the Precision representative, the float had been modified per service bulletin ACSB-84, which incorporates the Delrin float needle valve. The service bulletin was first issued in 1964. The Precision representative reported that the carburetor did not contain the correct needle valve or seat as required by the bulletin.

The Precision representative reported that the steel float needle exhibited normal wear but appeared to have been altered from its original appearance. The needle was not properly torqued in the bowl assembly. The float seat was safety wired as required but had a number of brass burrs around the top of the needle seating surface.

The FAA inspector reported that he spoke with the pilot regarding the aircraft's maintenance history. The pilot stated that when he first bought the aircraft, the engine would not idle. A maintenance facility removed and replaced the carburetor on October 30, 1998. Due to problems with the new carburetor, the original carburetor was reinstalled on December 15, 1998. The pilot reported that he did not remember having any modifications or updates performed on either carburetor.