SEA95LA083

The airplane's engine suddenly lost all power immediately after takeoff. The pilot attempted to switch fuel tanks and restart the engine, but his efforts were unsuccessful. The pilot force landed the airplane in rough terrain, causing substantial damage. An examination of the engine did not reveal evidence of pre-impact mechanical malfunctions. Fuel was found in the gascolator and fuel pump. The carburetor received thermal and impact damage. Pieces of the one-piece venturi were found in the lower portions of two engine intake tubes. Detailed examination of the carburetor and venturi pieces did not reveal evidence of pre-impact anomalies. The airplane had been operating as a glider towing aircraft while utilizing automotive fuel for several years prior to the accident.

On April 19, 1995, at 1223 hours Pacific daylight time, N60886, a Cessna 150J, registered to the Cascade Soaring Society, Inc., East Wenatchee, Washington, collided with terrain during a forced landing and was substantially damaged in Cashmere, Washington. The forced landing was precipitated by a loss of engine power during initial climbout after takeoff. The commercial pilot and his passenger received minor injuries. Visual meteorological conditions prevailed and no flight plan had been filed. The personal flight was en route to Wenatchee and was to be conducted under 14 CFR 91.

Records indicate that the airplane received 11.5 gallons of automotive fuel on April 16, 1995. The pilot stated that about 10 gallons of fuel were on board the airplane prior to departure from Cashmere on April 19, 1995. No records were found to verify the flight time from the last refueling.

According to the pilot, the pilot and the passenger departed from Wenatchee en route to Cashmere earlier in the day. A "comprehensive preflight" inspection was performed prior to departure from Wenatchee with no reported problems. After an uneventful flight and landing in Cashmere, the pilot taxied to runway 25 and took off. According to the pilot:

At 200 feet directly over the departure end of the runway the engine quit producing power. The [fuel] tank was switched without effect. Insufficient energy was available to return or take other action and touchdown was made avoiding major hazards and at a full stall flare.

The airplane impacted rough terrain and was substantially damaged. Flames were observed emanating from the engine firewall after impact. The fire was suppressed by the pilot and the local fire department.

The airplane, a 1969 Cessna 150J, was equipped with a Lycoming model O-320-E2D engine rated at 150 horsepower. According to the airplane's maintenance records, the engine had accumulated a total of 2,652 hours of operation, and was overhauled 768 operating hours prior to the accident. The airplane was also equipped with a fuel selector that had a LEFT- RIGHT-OFF valve. The airplane had a supplemental type certificate (STC) for the engine and fuel selector valve, as well as an STC for the use of automotive gasoline.

The airplane was utilized as a glider tow aircraft, and had accumulated a total time of 3,145 hours of flight time. The airplane received an annual inspection on April 1, 1994, about 93 operating hours prior to the accident. No unresolved discrepancies were found in the maintenance records.

The wreckage was examined by FAA aviation safety inspectors from Renton, Washington, at the accident site and again after the airplane had been removed. The examinations revealed the following:

Fuel was found in the gascolator and fuel pump. About 1-1/4 gallons of fuel were found in the right wing fuel tank, and about six gallons of fuel were found in the left wing fuel tank. A fuel line had been separated and was located in an area in which evidence of impact damage, thermal damage, and wire arcing had occurred.

An examination of the engine did not reveal evidence of pre- impact mechanical malfunction. Compression and valve train continuity was verified for all four cylinders. Pieces of the carburetor venturi were found in lower portions of the No. 1 and No. 4 cylinder intake tubes.

The carburetor, a Marvel-Schebler model MA-4SPA, had been separated from the engine and was separated into two halves. The recovered pieces of the carburetor were examined at the Safety Board's Metallurgical Laboratory in Washington, D.C. According to the metallurgist's factual report (attached):

Magnified visual examination of the fractures on all of the pieces found features indicative of overstress separation. The fractures on the received pieces of the supporting legs also showed significant bending deformation prior to separation.

Subsequent examination of the carburetor at facilities operated by Precision Airmotive in Everett, Washington, on October 18, 1995, under the supervision of the Safety Board, did not reveal evidence of pre-impact mechanical malfunction. The fuel screen, main nozzle assembly, main jet, and idle tube were disassembled and inspected; no blockages were found. The throttle arm was bent into the full throttle position.

The airworthiness directive AD 93-18-03 related to the carburetor one-piece venturi was complied with on April 22, 1994.