Abstract: A propeller oil control system for a turboprop engine of an aircraft includes an engine control unit and a propeller oil controller. The engine control unit is operable to determine a flight phase of the aircraft and is configured to supply control commands. The propeller oil controller is coupled to receive a supply of oil and to discharge the oil at a discharge oil pressure. The propeller oil controller includes an electrohydraulic servo valve that receives the control commands moves to a plurality of positions between a first position and a mid-position, and a plurality of positions between the mid-position and a second position. The engine control unit only commands the electrohydraulic servo valve to move out of the first position when the engine control unit determines the aircraft is conducting a take-off roll or the aircraft is in flight.

Abstract: A propeller pitch control system for a turboprop engine of an aircraft includes an engine control unit and a pitch control unit. The engine control unit is operable to determine a phase of flight of the aircraft and is configured to supply control commands. The pitch control unit is coupled to receive the control commands from the engine control unit and includes a housing, a beta piston, a position sensor, a beta tube, and an electrohydraulic valve. The engine control unit only commands the electrohydraulic valve to move the beta piston from the fully retracted position when the engine control unit determines the aircraft is conducting pre-takeoff roll taxiing operations or is conducting post landing touchdown operations.

Abstract: A propeller pitch control system for a turboprop engine of an aircraft includes a negative torque sensor, a full feather control valve assembly, and a feather valve assembly. The feather valve assembly is responsive to fluid pressures from the negative torque sensor and the control valve assembly to move between a plurality of positions. An engine control unit or a manual user interface can also be used to control the position of the feather.

Abstract: A propeller pitch control system for a turboprop engine of an aircraft includes a negative torque sensor, a full feather control valve assembly, and a feather valve assembly. The feather valve assembly is responsive to fluid pressures from the negative torque sensor and the control valve assembly to move between a plurality of positions. An engine control unit or a manual user interface can also be used to control the position of the feather.

Abstract: A propeller oil control system for a turboprop engine of an aircraft includes an engine control unit and a propeller oil controller. The engine control unit is operable to determine a flight phase of the aircraft and is configured to supply control commands. The propeller oil controller is coupled to receive a supply of oil and to discharge the oil at a discharge oil pressure. The propeller oil controller includes an electrohydraulic servo valve that receives the control commands moves to a plurality of positions between a first position and a mid-position, and a plurality of positions between the mid-position and a second position. The engine control unit only commands the electrohydraulic servo valve to move out of the first position when the engine control unit determines the aircraft is conducting a take-off roll or the aircraft is in flight.

Abstract: A propeller pitch control system for a turboprop engine of an aircraft includes an engine control unit and a pitch control unit. The engine control unit is operable to determine a phase of flight of the aircraft and is configured to supply control commands. The pitch control unit is coupled to receive the control commands from the engine control unit and includes a housing, a beta piston, a position sensor, a beta tube, and an electrohydraulic valve. The engine control unit only commands the electrohydraulic valve to move the beta piston from the fully retracted position when the engine control unit determines the aircraft is conducting pre-takeoff roll taxiing operations or is conducting post landing touchdown operations.

Abstract: Methods and systems are provided for monitoring the completion of a workflow checklist task. The apparatus comprises multiple sensors located in different points of an operational field space that is subject to the workflow checklist task. A synthetic sensing board that receives inputs from the plurality of sensors relating to the workflow checklist task. The synthetic sensing board has a core sensing circuit that processes the inputs and generates first order inferences about completion of the checklist task. It also assigns weighted values to each of the inputs and generates a second order inference about completion of the tasks based on summation of the weighted values of each input. A communications gateway transmits the first order and second order inferences about completion of the workflow checklist task to a display device.