On July 28, 1996, about 1430 Alaska daylight time, a wheel/ski equipped Cessna 185, N70018, crashed during takeoff from the Ruth Glacier, about 42 miles northwest of Talkeetna, Alaska. The airplane was being operated as a visual flight rules (VFR) local area sightseeing flight under Title 14 CFR Part 135 when the accident occurred. The airplane, registered to and operated by Talkeetna Air Taxi Inc., Talkeetna, Alaska, was destroyed. The certificated airline transport pilot and three passengers were not injured. Two passengers received minor injuries. Visual meteorological conditions prevailed. A VFR flight plan was filed. The operator reported the pilot landed the airplane with 5 tourists aboard in an upslope direction on the glacier near the Sheldon mountain house. The landing area was located at 5,700 feet mean sea level. The landing area was about 2,500 feet long and sloped downhill about 100 feet. The pilot reported during a downhill takeoff, the engine was producing full power and the airplane became airborne at 65 MPH. The engine momentarily lost power and surged about 3 times from full power to almost no power. The pilot turned on the fuel boost pump, but full power was not restored. The airplane settled onto snow covered terrain and then collided with the edge of a crevasse. The total flight lasted about 30 seconds. The airplane received damage to the landing gear, fuselage, and empennage. The pilot reported the snow was wet and dense and he sank into the snow 8 to 12 inches while walking. The accident occurred in the Denali National Park. A national park ranger reported he interviewed two employees of an air taxi operator who visited the accident site on August 7, 1996, to retrieve additional wreckage. The employees reported they walked along the ski tracks produced by the accident airplane. The tracks were reported to have extended approximately 4,000 feet along the surface of the snow before leaving the surface at the edge of a crevasse. About 50 yards beyond the crevasse, additional ski tracks were noted skipping on the snow surface until the point of rest at the accident crevasse. The employees provided a similar statement to a Federal Aviation Administration (FAA) inspector. On August 2, 1996, an FAA airworthiness inspector conducted an examination of the accident airplane's engine and fuel system. No discrepancies were noted. On August 8, 1996, the inspector conducted another examination in which the airplane fuselage was strapped to a trailer and the engine was started. He reported the engine ran normally with no observed discrepancies.