NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The airline transport pilot was repositioning the airplane to its home base after maintenance was completed at a repair station. The pilot filed an instrument flight rules (IFR) flight plan with a cruise altitude of 9,000 ft mean sea level (msl). The en route portion of the flight to the destination was uneventful. Before descending to approach altitude, the pilot contacted approach control and reported that he had received weather information for the destination airport. The pilot then requested and was given clearance to fly the area navigation (RNAV) approach to runway 7. Approach control cleared the pilot to descend to 3,000 ft msl and issued pilot reports for icing. The pilot flew the RNAV approach to runway 7, tracking inbound to the airport on the published approach course. About 5.8 miles from the airport, the pilot cancelled his IFR clearance and continued inbound under visual flight rules. His recorded altitude at the time of IFR cancellation was 2,700 ft msl. Reported weather at the airport at the time of the accident included a ceiling of 1,700 ft above ground level (2,649 ft msl) and wind from 240 degrees at 9 kts, gusting to 14 kts, and variable from 240 to 330 degrees. One witness at the airport saw the airplane enter a downwind leg to land into the wind on runway 25. As the airplane began its turn from the base leg to final, several other witnesses saw it nose down and descend to impact in wooded terrain about 300 ft short of the runway threshold.
A postaccident weather study showed high icing potential within the cloud layers above the surface and a likelihood of moderate or greater icing along the airplane's route of flight until the airplane descended below the cloud ceiling. Because the surface temperature was below freezing, any structural ice that built up on the airplane while it descended through the clouds would not have melted after the airplane descended below the cloud ceiling.
An examination of the airplane revealed no preimpact mechanical malfunctions or anomalies that would have precluded normal operations. Data recovered from the airplane's Remote Data Module showed that the airplane's anti-ice tank switch was turned on about 7 minutes 30 seconds before the accident and remained on for 1 minute 50 seconds. The switch was then turned off and remained off for the remainder of the flight. The airplane's flaps were extended to the "HALF" position about 2 minutes 50 seconds before the accident. Just before the data ended, the airplane's pitch and bank increased, and the stall warning activated. In the last 3 seconds of data, the airplane's bank angle was 48 to 50 degrees, and the indicated airspeed was between 87 and 90 kts. The Pilot's Operating Handbook for the airplane showed that at 60 degrees of bank with half flaps, the airplane's stall speed was 95 kts. It is possible that, during the approach, ice accumulated on the airplane, which may have increased the airplane's stall speed. However, regardless of whether or not structural ice was present, during the turn to final, the pilot allowed the airspeed to decrease below the airplane's published stall speed. As a result, the wing's critical angle-of-attack was exceeded, and the airplane entered an aerodynamic stall and departed controlled flight.