TOK, AK, USA
N8597D
PIPER PA-18
AS THE AIRPLANE REACHED THE END OF THE 600-FT STRIP, THE PILOT APPLIED THE SECOND NOTCH OF FLAPS. THE AIRPLANE BECAME AIRBORNE FOR ABOUT 20 FT, AND THEN SETTLED INTO BRUSH. THE PASSENGER REPORTED THAT 'MY IMPRESSION IS THAT WE LACKED OR LOST ADEQUATE POWER TO MAINTAIN FLIGHT...' ANOTHER COMPANY PA-18 AT SITE HAD NO DIFFICULTY IN FERRYING EVERYONE FROM THE SITE. EXAMINATION OF THE ENGINE SHOWED THAT AN EXHAUST CAM LOBE WAS 30-40% WORN, AND THE ASSOCIATED CAM FOLLOWER WAS WORN AND DISH SHAPED. THE DEPTH OF THE WORN AREAS EXCEEDED THE DEPTH OF THE NITRATED SURFACE. ACCORDING TO THE DIR OF MAINT, A 50-HR INSPECTION WAS PERFORMED PREVIOUS TO THIS FLIGHT AND METAL PARTICLES WERE FOUND IN THE OIL SCREEN.
On September 2, 1994, at 1126 Alaska daylight time, a wheel equipped Piper PA-18 airplane, N8597D, registered to the pilot, and operated by 40 Mile Air Ltd., of Tok, Alaska, crashed beyond the departure end of an airstrip during a takeoff attempt. The air taxi flight, operating under 14 CFR Part 135, was departing the accident site, which is located 24 nautical miles southwest of Tok on Natahona Creek, and the destination was Tok. A VFR flight plan was filed and visual meteorological conditions prevailed. The pilot and the passenger were not injured and the airplane was substantially damaged. According to the pilot, during an interview with FAA Inspector Steve Ketzer, he did not perform a engine run up because of the gravel and he did not check nor did he use carburetor heat prior to take off. The pilot stated that when he reached the end of the 600 foot long airstrip he applied a second notch of flaps and the airplane became airborne. The airplane then settled and the wheels struck some brush and the airplane crashed. The pilot could not recall the airspeed or the engine tachometer readings during the take off roll. Examination of the engine showed that one of the exhaust cam lodes on the camshaft was 30 to 40 percent worn and the cam follower was worn and dish shaped. According to Randy Rallo, Director of Maintenance for 40 Mile Air LTD., previous to this flight they performed a 50 hour inspection on the airplane and found metal particles in the oil screen. He further stated the wear on the cam lobe and cam follower went beyond the nitrated surface. Another PA-18, a company airplane, was also on the airstrip and had no difficulty in ferrying everyone from the accident site.
THE WORN CAM SHAFT LOBE AND WORN VALVE LIFTER.
Source: NTSB Aviation Accident Database
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