The pilot reported that, after landing on a snow-covered, off-airport landing site in Big Lake, Alaska, he was positioning the Cessna 180 for parking. He added that the left ski broke through the ice, followed by the right ski.
He reported that he had not seen the area of “soft/thin” ice before taxiing.
The airplane sustained substantial damage to the fuselage.
The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.
Probable cause: The pilot’s selection of unsuitable terrain for landing, which led to both skis breaking through the ice while positioning the airplane after landing.
NTSB Identification: GAA18CA136
This February 2018 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
No guarantee of course, but a useful technique is to extend “lake landing” practice to the taxi/ parking phase. When landing first do a touch and go with enough weight on the skis to depress the snow,while maintaining enough speed to easily lift off again. Circle back and land in those tracks,if they are turning dark don’t land, it is water. Once down taxi at the highest safe speed back into those tracks, that is where you will park as it is as close to “proven” ice as you have. Need to park elsewhere?, circle over the parking area and check your tracks, if they do not turn dark, park on those tracks. If the tracks are turning dark keep the speed up and move to another area. Remember that the aircraft skis may well have less lbs/ft than your feet,so be very careful getting out of the aircraft and walking to shore.