On December 1, 2013, a Beechcraft B36TC turbocharged Bonanza crashed in mountainous terrain in central Idaho while en route from Baker, Ore., to Butte, Mon. All five occupants were killed. The NTSB accident report stated the probable cause of the accident was “continued flight into known light-to-moderate icing conditions over mountainous terrain.” Reporting stations along the flight path advertised widespread marginal VFR and Airmets had been issued for moderate icing, mountain obscuration and moderate turbulence, and wind shear. There also were numerous pilot reports of icing conditions for various locations in Idaho and along the route of flight.
In reality, the NTSB’s finding in this accident might more properly be called a result rather than a probable cause. In my view, the clear cause of this accident was poor risk management by the Bonanza pilot. I know it’s always easy in hindsight to come to such a conclusion, yet the pilot of this Bonanza launched on this flight despite the fact that he was flying an aircraft that was not equipped for flight in known icing conditions. Even a cursory review of the weather would have revealed the almost certain presence of ice in the clouds at the minimum en route altitude of 13,000 feet.
