AVALON, CA, USA
N93508
CESSNA 152
After an over water flight to Catalina Island, the pilot reported having engine trouble and that he was attempting to return to the Catalina airport. The airport is located on a mountain top in an area of the island with steep mountainous terrain. A witness saw the aircraft and heard the engine repeatedly accelerate to full power, interrupted by sputtering and periods of silence. A second witness reported seeing the aircraft in a turn attempting to gain altitude as it approached the higher terrain. Ten minutes later, fire department units responding to reports of a brush fire found the burning aircraft wreckage. The weather at the time included a 20 degree spread between dew point and ambient temperature. Carburetor icing probability charts revealed the aircraft had flown in conditions conducive to moderate icing at cruise power and serious icing at glide power.
HISTORY OF FLIGHT On April 5, 1994, at 1846 Pacific daylight time, a Cessna 152, N93508, was destroyed by impact forces and a post crash fire during a declared emergency approach to the airport at Avalon, California. The aircraft was owned and operated by Orange County Flight Center, Santa Ana, California, and was rented by the pilot for a solo personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed for the operation. The certificated private pilot, the sole occupant, sustained fatal injuries. The flight originated from the John Wayne airport, Santa Ana, California, at 1748 on the day of the accident. The pilot requested and received from Coast Approach Control a clearance to 4,500 feet enroute to Catalina Island. Afterwards, he was cleared for a descent and that radar service was terminated. A few minutes after being cleared for descent, the pilot made a radio call in the blind reporting, "Catalina traffic, 508 has engine trouble. I'm making it back to the airport." Approach asked him to say his position. The pilot's next transmission was: "position ...I'm on the ah ... side." Approach made a second call, telling him that they did not know his location and asking him for his destination airport. The pilot replied "Catalina." Approach asked him to confirm that he was having an emergency north of the field, but there were no further transmissions. Approach tried to contact the pilot four more times. A ground witness reported seeing and hearing an aircraft in the vicinity a few minutes before the time of the crash. The witness estimated the altitude of the aircraft to have been 2,000 feet msl while on a southwesterly heading. The witness said he observed the aircraft for about 4 minutes, and during that time the aircraft maintained altitude and heading. He stated that what first attracted his attention to the aircraft was the unusual engine sounds. He heard intermittent sounds of an engine accelerating to full power interrupted by sputtering and 5 to 10 second periods of silence, during which time he described the aircraft as gliding silently. A second ground witness reported seeing the aircraft in what he judged as an attempt to gain altitude, and perform two 360 degree turns in order for the aircraft to clear the higher terrain. He last saw the aircraft as it descended below a ridge line. He stated that he did not believe that the aircraft would be able to clear the higher terrain. About 10 minutes later, an aircraft flying in the vicinity of Santa Catalina Island reported a brush fire approximately 2 miles west of the airport. Los Angeles County Fire Department units responded to the location and found the wreckage of the aircraft on fire. METEOROLOGICAL INFORMATION The weather at the time of the accident, as reported by the Long Beach weather observation facility, included a 20 degree spread between dew point and ambient temperature. According to Federal Aviation Administration carburetor icing probability, the aircraft had been flown in conditions conducive to moderate carburetor icing at cruise power, and serious icing conditions at glide power. WRECKAGE AND IMPACT INFORMATION The main wreckage of the aircraft was found burned and inverted. The final heading of the aircraft after impact was estimated to have been 015 degrees. The aircraft wreckage was contained within an approximate 200 foot perimeter and was distributed along a 340 degree axis toward a 20 degree up-slope of rising terrain. The left wing, with fuel remaining in the tank, was about 20 feet from the main fuselage. The left fuel tank showed evidence of hydraulic deformation. The right wing was destroyed by impact and post crash fire. The finger screen in the left wing tank was clean and unblocked. The empennage was found separated and inverted. It exhibited both impact and fire damage. The propeller was found separated from the engine at the crankshaft flange. The blades exhibited chord-wise scoring and leading edge gouges. One blade exhibited an "S" bend with a torsional twist. The spinner exhibited rotational crushing. The left front seat had separated from the seat track and was found approximately 40 feet north of the main wreckage. Both sets of seat belt latches were recovered. Neither set was found in a latched position. The engine was found separated from the engine mount and exhibited impact damage, but showed no evidence of fire involvement. The engine exhaust manifold exhibited crushing deformation. The muffler was crushed flat. Flight control surfaces and cables exhibited both impact and fire damage. The elevator trim was found with one degree tab up. The flap actuator was found in the full up position. The engine accessory section sustained impact damage. Both magnetos were recovered; one was in a fragmented condition, while the other had sustained visible impact damage. The oil sump had separated from the engine and exhibited impact damage. The vacuum pump was fractured and was partially separated from the engine. The oil filler cap and dipstick had also separated from the engine. A fuel sample taken at the accident scene was reported by the aircraft's manufacturer representative to have been free of visible contamination and gave the appearance of aviation fuel. The carburetor was separated and exhibited impact and fire damage. The carburetor air box was not located. The induction air filter was intact and exhibited several punctures. The fuel selector exhibited impact damage. The selector handle was separated. The fuel selector valve was inspected visually and was found to be in a closed position. The engine instruments exhibited impact and fire damage. The directional gyro showed a static reading of 358 degrees. The engine tachometer needle indicated 500 rpm. After recovery to a storage facility, the engine was disassembled and inspected. All four cylinders displayed combustion patterns. The camshaft and lifter bodies had wear patterns. Valve train continuity was established through hand rotation, with all connecting rods rotating freely on the crankshaft. The camshaft lobes exhibited wear. The oil pump housing and impeller gears had residual oil present. The accessory drive gears, including the crankshaft gear, were seated and displayed wear patterns. The carburetor, P/N 10-5267, S/N DT-0-617, was disassembled. The fuel screen was clean and unblocked. The single piece venturi was found with a molten piece of aluminum inside. There was no contamination found in the float bowl. The metal floats were stamped "6-84". Initially, the remaining intact magneto, Slick P/N 4381, S/N 920800551, would not produce spark. The case exhibited impact damage. The magneto was disassembled and the internal screws were found bent. After the magneto was reassembled it produced a spark from one terminal. The four upper spark plugs showed worn oval patterns and dry electrodes with coloration. Two of the lower spark plugs were found broken. The cylinders were recovered to an engine rebuild facility where they were disassembled and examined. All valves moved freely in their guides and were seated with minor leaking. All dimensions and tolerances were within limits, with the number four exhaust valve showing signs of metal transfer. MEDICAL AND PATHOLOGICAL INFORMATION The Los Angeles County Coroner performed an autopsy on the pilot, with samples retained for toxicological analysis by the FAA Civil Aero Medical Institute (CAMI)in Oklahoma City, OK. CAMI reported the presence of Sertraline in the blood, along with Acetaminophen measured at a level of 16.200 (ug/ml, ug/g).
the failure of the pilot to apply carburetor heat as appropriate while conducting flight in conditions conducive for carburetor icing. A factor in the accident was the unsuitable steep mountainous terrain for a forced landing.
Source: NTSB Aviation Accident Database
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