Priority Air Charter

The two pilots departed in a turbine powered DC-3C at maximum gross weight for a repositioning flight. The airplane was part of a test program for new, higher horsepower engine installation. Soon after liftoff and about 3 seconds after decision speed (V1), the left engine lost total power. The propeller began to auto-feather but stopped feathering about 3 seconds after the power loss. The airplane yawed and banked to the left, descended, and impacted terrain. Recorded engine data indicated the power loss was due to an engine flameout; however, examination of the engine did not determine a reason for the flameout or the auto-feather system interruption. While it is plausible that an air pocket developed in the fuel system during the refueling just before the flight, this scenario was not able to be tested or confirmed. It is possible that the auto-feather system interruption would have occurred if the left power lever was manually retarded during the auto-feather sequence. The power loss and auto-feather system interruption occurred during a critical, time-sensitive phase of flight since the airplane was at low altitude and below minimum controllable airspeed (Vmc). The acutely transitional phase of flight would have challenged the pilots' ability to manually feather the propeller quickly and accurately. The time available for the crew to respond to the unexpected event was likely less than needed to recognize the problem and take this necessary action – even as an immediate action checklist/memory item.

The pilot departed with the airplane contaminated with ice, into known severe icing conditions, and was unable to maintain altitude, subsequently impacting trees and terrain. Witnesses reported the accident airplane arrived at the departure airport contaminated with ice. Several witnesses stated they asked the pilot if he needed the airplane deiced prior to his next departure and the pilot stated he did not need any deice service. Several witnesses said they noticed the pilot chipping-off ice from the airplane prior to his departure. While en route the pilot reported the airplane had encountered icing conditions and he was unable to maintain altitude. Several thick pieces of ice were recovered around the accident site and one of the recovered ice pieces had a semicircular shaped edge that was consistent with a leading edge of an airfoil. No pre-impact anomalies were found with the leading edge de-ice boots that were installed on both wings, vertical and horizontal stabilizers, and wing struts. Federal Aviation Regulations state that all ice contamination shall be removed prior to flight. The Cessna 208B Pilot Operating Handbook indicates that continued flight into known icing conditions must be avoided.