Swearingen SA226T Merlin III

During takeoff from the departure airport, as the pilot advanced the throttles, the aircraft made a "sudden turn to the right." The pilot successfully aborted the takeoff, performed an engine run-up, and then took off without incident. The pilot experienced no anomalies during the second takeoff or the flight to the destination airport. As he reduced the power while in the traffic pattern, at the destination airport, the left engine accelerated to 60 percent power. The pilot reported to the tower that he had "one engine surging and another engine that seems like I lost control or speed." The pilot advanced and retarded the throttles and the engines responded appropriately, so he continued the approach. As the pilot flared the airplane for landing, the left engine surged to 65 percent power with the throttle lever in the "idle" position. The airplane immediately turned to the right; the right wing dropped and impacted the ground. Disassembly of the engines revealed no anomalies to account for surging, or for an uncommanded increase in power or lack of throttle response. Functional testing of the fuel control units and fuel pumps revealed the flight idle fuel flow rate was 237 and 312 pounds per hour (pph), for the left and right engines, respectively. These figures were higher than the new production specification of 214 pph. According to the manufacturer, flight idle fuel flow impacts thrust produced when the power levers are set to the flight idle position and differences in fuel flow can result in an asymmetrical thrust condition.

The pilot departed Front Range Airport (elevation 5512 feet) at approximately 2008, climbed to 7,000 feet msl, accelerated to 270 knots, and requested his IFR clearance. Weather at the time of N950TT's departure was 500 feet overcast; witnesses reported the tops of the thin cloud condition were 8,500 feet msl and it was very dark on top (no stars or moon). The pilot made several changes in airspeed and climb rate until radar indicated that he had entered an 8,500 fpm decent. The pilot reported to ATC that he had 'stalled' the airplane. Radar indicated that he then climbed at 7,500 fpm until his estimated airspeed was 10 knots, and then subsequently descended again at 8,400 fpm until he impacted the frozen ground. The pilot had flown 4 times for 7 hours in the previous 40 days. Five airline pilots, each of who had 3,000 to 5,000 hours in Swearingens, stated individually that even though the airplane is single pilot certified, they believed that 'its a two pilot airplane--because the work load is too high.'

On final approach to Ushuaia Airport, following an uneventful cargo flight from Río Grande, the twin engine aircraft collided with a flock of birds. The windshield was broken and the left engine lost power. The crew was able to continue the approach and landing. After touchdown, the aircraft went out of control and collided with a snow wall. Both pilots escaped with minor injuries and the aircraft was damaged beyond repair.