System and method for rotorcraft autorotation entry assist

A flight control computer, comprising:

• a processor;
• and
• a non-transitory computer-readable storage medium storing a program to be executed by the processor, the program including instructions for:
• monitoring an operating state of an engine of a rotorcraft;
• detecting a failure of the engine according to the operating state;
• and
• engaging, in response to the failures of the engine, an autorotation entry assist process, comprising instructions for:
• determining if a pilot has released manual control of the rotorcraft;
• determining a target flight control setting in response to determining that the pilot has released manual control of the rotorcraft and in response to a main rotor revolutions per minute (RPM) of a main rotor of the rotorcraft being below a predetermined threshold;
• generating a rotor RPM related command according to at least one of the main rotor RPM or a rate of change of the main rotor RPM, wherein the one or more RPM related commands comprises a first command to change a collective blade pitch angle of blades of the main rotor in proportion to a rate of change of the main rotor RPM after the engine failure;
• and
• controlling a flight characteristic of the main rotor by controlling a flight control of the rotorcraft connected to the main rotor according to the rotor RPM related command.

A method, comprising:

• receiving engine performance data indicating an engine operating condition of one or more engines of a rotorcraft, wherein the one or more engines drive a main rotor of the rotorcraft during operation of the one or more engines
• detecting an engine failure condition of the one or more engines according to the performance data;
• and
• engaging an automated autorotation entry assist process in response to at least detecting the engine failure, wherein the automated autorotation entry assist process comprises:
• receiving a signal indicating a measured main rotor revolutions per minute (RPM) of the main rotor;
• detecting an in-detent state in response to a pilot being out of manual control of a pilot control of the rotorcraft;
• generating, in response to detecting the in-detent state, one or more rotor RPM related commands according to at least a target main rotor RPM and the measured main rotor RPM, wherein the one or more RPM related commands comprises a first command to change a collective blade pitch angle of blades of the main rotor in proportion to a rate of change of the main rotor RPM after the engine failure;
• and
• sending a first signal to a flight control of the rotorcraft according to the one or more rotor RPM related commands, and controlling the flight control according to the one or more rotor RPM related commands.