Cessna 208B Caravan, Alliance, Neb., Feb. 8, 2007–The commercial pilot of Caravan N1116Y was seriously injured when the postal cargo airplane hit the roof of a metal building and then the ground during a nonprecision approach to Runway 12 at Alliance Municipal Airport (AIA) in night IMC. The pilot, who had filed an IFR flight plan, had been cleared for the VOR 30 approach but at 2:09 a.m. requested a change to the VOR 12 approach. At 2:19, the recorded weather at AIA was wind 070 degrees at 4 knots, visibility 1 sm, mist, overcast 200 feet, temperature -6 degrees C, dew point -7 degrees C; altimeter 30.17 inches.
A witness, a train engineer, felt a shock wave on his locomotive and noticed it had a coating of ice. He also reported that it was foggy. He found the Suburban Air Freight Caravan in a ditch, with a power pole leaning across the roadway. The airplane’s fuselage had split open on its left side. The right wing and empennage were still attached to the fuselage. The inboard section of the left wing was attached but the outboard section was found near the scar where the airplane first hit the ground.
Rime ice, from one-tenth of an inch to one-eighth of an inch thick, was found on the leading-edge boots of the wings, elevators and fin and on the propeller
de-icing boots, as well as on the unprotected surfaces of the aircraft. The leading surface of the right strobe light had the most ice, about three-eighths of an inch.