This November 2008 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Beech Duke. Injuries: None. Location: Rock River, Wyo. Aircraft damage: Substantial.
What reportedly happened: The pilot, who was on a cross-country flight in IFR conditions, reported that he was picking up clear ice in clouds while the airplane was in cruise flight at 16,000 feet MSL. In an effort to get out of the icing conditions, he requested and received clearance to progressively lower altitudes down to 10,000 feet. The airplane continued to accumulate ice. The pilot requested a turn, and this was denied by the controller as there were two other airplanes in the vicinity with similar icing problems. The pilot then requested and received clearance to descend to 9,000 feet, where he could see portions of the ground. At this point, the windshield was completely covered with clear ice, as were the unprotected portions of the aircraft. Both engines were operating at full power. The pilot informed the controller that he needed to descend further. At an altitude of 7,500 feet, he circled several times attempting to see if he could reach an airport for landing. No ice had melted or come off the airplane, and the weather was deteriorating. The pilot stated that he had no forward visibility due to the clear ice.
The pilot decided to land on a highway. During the approach the airplane hit a power line, which severed the upper half of the rudder and vertical stabilizer. The pilot turned the airplane slightly left, and landed in a terraced field next to the highway. During the landing roll, the landing gear was sheared off when the airplane encountered a ditch.
Probable cause: The failure to maintain clearance from a power line due to the lack of forward visibility because of an ice-covered windshield. Contributing to the accident was the flight’s encounter with icing weather conditions.
For more information: NTSB.gov