On May 13, 2002, about 1030 Alaska daylight time, a tundra tire-equipped Bellanca 7GCBC airplane, N3JK, sustained substantial damage when the left main landing gear collapsed while landing at the Tanis Mesa airstrip, located about 42 miles southeast of Yakutat, Alaska. The commercial pilot and the one passenger were not injured. The 14 CFR Part 91 business (hunt/guide) flight operated in visual meteorological conditions without a flight plan. The flight departed Yakutat about 1010. The intermediate destination was the Tanis Mesa airstrip, with a return to Yakutat. The pilot/owner of the airplane contacted the NTSB investigator-in-charge (IIC) by telephone on May 13 at 1240 to report the accident. During the ensuing conversation, he said he was an owner of a guide business, and was landing his tailwheel airplane at the Tanis Mesa turf airstrip for a routine check on a hunting guide and clients. He said that soon after a normal touchdown, the left main landing gear collapsed, and the left wing struck the ground, damaging the outboard two feet of the wing and the left wing lift strut. The pilot said he was unaware of any pre-existing mechanical problems with the airplane, and that the airplane was equipped with 24-inch tundra tires. Postaccident discussion between the NTSB IIC and an aviation mechanic who repaired the airplane, disclosed that the mechanic discovered what he believed to be a pre-existing crack in the left main landing gear strut at the point the gear leg fractured.