Incident Overview
A pilot reported an incident involving ice accumulation and a failed deice boot system during an instrument flight rules (IFR) flight. The pilot stated that during climbout, he frequently checked the wings for ice accumulation and observed what appeared to be a trace of ice. At approximately 13,000 feet mean sea level (msl), with almost no climb at 125 knots indicated airspeed, the pilot pulled the yoke back slightly to climb, and the aircraft began to shudder.
Diversion and Approach
The pilot decided to divert and again checked the wings, observing what he described as a trace of ice. He cycled the deice boots, but there was no apparent change in wing appearance. During the approach, he cycled the boots again between 3,000 and 2,000 feet msl. The pilot stated that about 20 to 30 feet above the surface, he started a slight roundout. When he eased back on the yoke, the airplane shuddered and the nose did not raise.
Hard Landing
At that point, the pilot was ready to touch down. He pulled back on the yoke while adding power; however, the airplane landed hard and was damaged.
Post-Incident Testing
Later, the surface deice system was tested. The boots did not hold pressure due to multiple wing boot holes and a shuttle valve internal leak. Functional tests revealed that the control valves did not direct proper pressure to the system, and the shuttle valves did not direct pressure properly to the boots, with leakage to the vacuum side of the valves.