Incident Overview
A flight operating under 14 CFR Part 135 experienced unforecast icing while approaching its original destination. The pilot reported that the airplane's windshield deicing plate was unable to clear ice from the windshield surface, and the entire windshield became ice-covered.
Diversion and Approach
Due to the icing conditions, the pilot decided to divert to an alternate airport, citing better instrument approach facilities. During the second instrument approach, FAA air traffic control personnel located next to the runway guided the pilot to a landing.
Landing and Collapse
The pilot stated that the airplane firmly contacted the runway at touchdown. During the landing roll, the left main landing gear collapsed, and the airplane collided with taxiway signs and runway edge lights.
Post-Accident Investigation
On-scene investigation revealed approximately 1½ inches of ice on the windshield. Shortly after the airplane came to a stop, the area of the windshield deicing plate was clear. The unbooted areas of the airplane's wings had 2 to 2½ inches of ice.