The aircraft was landing on Runway 03, following a normal approach at 60 mph with two stages of flap selected. The pilot stated that the flare was high and resulted in a heavy landing, after which he slowed the aircraft to taxi speed, as normal. However, after taxiing down the runway for about 100 yds, the left main landing gear collapsed and the left wingtip contacted the surface. The aircraft came to rest on the edge of the runway, having swung through 90º. Its two occupants were uninjured.