What happened
The pilot initially contacted Flight Service Station (FSS) at 1101 with intentions of canceling a proposed flight due to weather concerns. A briefing indicated that Kansas City was reporting very light rime icing between 4,000 and 11,000 feet, supported by a Pilot Report (PIREP) of light to moderate rime ice located 30 miles south of the airport between 6,000 and 8,000 feet. The pilot stated he needed to leave immediately and initiated a reservation and flight plan.
At 1217, the pilot received a weather update suggesting he could expect icing while descending through the clouds. En route, while flying on top at 11,000 feet, the pilot diverted to Kansas City. When cleared to descend, the pilot reported being still in the clouds and accumulating ice, requesting permission to remain at 11,000 feet until clear of the cloud layer.
At 1439, air traffic control advised the pilot that a descent must begin shortly as he was only 13 miles from the outer marker. During the subsequent descent, the aircraft disappeared from radar and was observed emerging from the overcast in a near-vertical dive. The landing gear were found in the down position.
Findings
The aircraft was not equipped with de-icing equipment. No ice was observed on the wreckage upon recovery. The pilot had been aware of icing conditions aloft but continued the descent into the cloud layer despite prior warnings and personal intentions to cancel the flight due to weather.