On March 31, 1997, about 1530 Alaska standard time, a ski equipped Cessna 170B airplane, N4549C, sustained substantial damage while landing on frozen East Twin Lake, located about 33 miles south of Manley Hot Springs, Alaska. The airline transport certificated pilot and the one passenger aboard were not injured. The 14 CFR Part 91 pleasure flight departed Fairbanks, Alaska, about 1200. Visual meteorological conditions prevailed, and a VFR flight plan was in effect. During a telephone conversation with the NTSB investigator-in-charge on April 8, the pilot related he had just landed the accident airplane on East Twin Lake to go fishing. During the latter part of the landing roll, the right ski broke through the ice crust, the right main landing gear was pulled from the gear box, and the gear box was pulled away from fuselage. The right main landing gear collapsed, and the right wing struck the ground. The NTSB Form 6120.1/2 was not returned by the pilot.