On April 4, 2004, at 1715 Alaska daylight time, a tailwheel-equipped amphibious Grumman G21 airplane, N22932, sustained substantial damage when the left main landing gear collapsed following a loss of control while landing at the Unalaska Airport, Unalaska, Alaska. The two airline transport certificated pilots, and the seven passengers, were not injured. The Title 14, CFR Part 135 scheduled commuter flight was operated as Flight 325 by Peninsula Airways, Anchorage, Alaska, doing business as PenAir. The flight departed Akutan, Alaska, at 1645, en route to Unalaska. Visual meteorological conditions prevailed, and a visual flight rules (VFR) flight plan was in effect. According to information received from the operator's vice president, and from the NTSB Pilot/Operator Aircraft Accident Report submitted by the flight crew, the pilot-in-command of the flight was a check airman observing and instructing a recently upgraded captain during his initial operating experience. The new captain was the pilot flying, and occupied the left seat at the time of the accident. The check airman occupied the right seat pilot's station which was equipped with all flight controls, but did not have brake pedals. The airplane made an uneventful wheel landing touchdown on runway 30, but during the latter portion of the landing roll, as the tailwheel touched the runway, the airplane swerved hard to the left. The pilot flying indicated he applied full right brake, full right rudder, and differential power to arrest the turn. The airplane began a turn towards the center of the runway, and the rudder and differential power were neutralized. The airplane continued turning sharply to the right, and as the nose of the airplane passed approximately 20-25 degrees right of the runway centerline, the left main landing gear collapsed. The airplane slid on its fuselage for about 40 feet, before coming to rest on the runway. Reported wind conditions at the time of the accident were 7 knots gusting to 14 knots, from 027 degrees magnetic, or nearly a direct right crosswind. Discussions with the operator's vice president, and a review of digital photographs provided by the operator, disclosed that the airplane received structural damage to the bottom and right side of the fuselage. Interviews with and documents supplied by the FAA assistant principal operations inspector for the operator, disclosed the flying pilot had received an abbreviated level of transition training for the G21 airplane prior to receiving his G21 captain's check ride from the company check airman. The company check airman who administered the check ride and the flight training was the non-flying captain on the accident flight. According to the FAA inspector, the flying pilot had not met the operator's prescribed (and FAA approved) minimum training requirements for a G21 captain. He noted that only two of the four required training flights were completed, that only three of the required 12 wheel landings were accomplished, and that prohibited simultaneous flight checking and flight training were conducted. The FAA inspector indicated that prior to commencement of training in the G21, the flying pilot had accrued approximately 7 hours total tailwheel experience, collected over approximately 7 years. He received 1.8 hours of flight training in the G21, which included .1 (6 minutes) allocated for completion of the entire flight check requirements. A review of the airplane's maintenance records disclosed no evidence of any significant preaccident mechanical problems with the airplane, and no evidence of any preaccident mechanical anomalies were reported by the operator during the postaccident inspection.