N1155C

The pilot reported that while flying, he observed injured snowmobilers waving for help. After radioing for assistance, the pilot gathered emergency supplies from within the airplane and prepared to air drop the supplies to the snowmobilers and configured the airplane for a slow approach over their location. After a successful drop, he applied full power and banked left to avoid terrain. The airplane encountered a downdraft and started to descend with the left wing low. Despite the pilot’s control inputs, the airplane continued to lose altitude until it impacted the glacier below. The airplane’s firewall and both wings were substantially damaged. The pilot reported no mechanical failures or malfunctions that would have precluded normal flight.