Method and system for operating an aircraft powerplant

A system for operating an aircraft powerplant comprising an engine coupled to a variable-pitch propeller, the system comprising:

• at least one processing unit;
• and
• at least one non-transitory computer-readable memory having stored thereon program instructions executable by the processing unit for:
• receiving, from a pilot of the aircraft, an input indicative of thrust demanded from the powerplant, the input including a position of a power lever;
• operating the powerplant according to the input indicative of thrust demanded from the powerplant and according to a first setting for a propeller rotational speed;
• receiving, from the pilot of the aircraft via a cockpit input other than the position of the power lever, a pilot request to change the propeller rotational speed from the first setting to a second setting while the powerplant is operated according to the input indicative of thrust demanded from the powerplant;
• determining a power need for the engine based on the input indicative of thrust demanded from the powerplant;
• determining whether the power need is compatible with the second setting for the propeller rotational speed;
• when the power need is compatible with the second setting for the propeller rotational speed, modifying a command for at least one of fuel flow to the engine and oil flow to the propeller to govern the powerplant in accordance with the second setting for the propeller rotational speed;
• and
• when the power need is incompatible with the second setting for the propeller rotational speed, overriding the pilot request to change the propeller rotational speed from the first setting to the second setting by maintaining the first setting for the propeller rotational speed despite the pilot request to change the propeller rotational speed from the first setting to the second setting;
• wherein:
• the second setting for the propeller rotational speed is lower than a maximum propeller rotational speed;
• the engine is a first engine and the variable-pitch propeller is a first variable-pitch propeller;
• the aircraft has a twin engine configuration including a second engine coupled to a second variable-pitch propeller;
• and
• the instructions are executable by the processing unit for:
• when a failure of the second engine is detected while the powerplant is governed in accordance with the second setting for the propeller rotational speed, governing the powerplant in accordance with the maximum propeller rotational speed for the first variable-pitch propeller;
• and
• when the pilot selects take-off power through the power lever while the powerplant is governed in accordance with the second setting during cruise, causing, by a control system of the aircraft, the powerplant to be governed in accordance with the maximum propeller rotational speed for the first variable-pitch propeller.

An aircraft powerplant comprising:

• a gas turbine engine;
• a variable-pitch propeller coupled to the gas turbine engine;
• and
• a controller coupled to the gas turbine engine and the variable-pitch propeller and configured for:
• receiving, from a pilot of the aircraft, an input indicative of thrust demanded from the powerplant, the input including a position of a power lever;
• operating the powerplant according to the input indicative of thrust demanded from the powerplant and according to a first setting for a propeller rotational speed;
• receiving, from the pilot of the aircraft via a cockpit input other than the position of the power lever, a pilot request to change the propeller rotational speed from the first setting to a second setting while the powerplant is operated according to the input indicative of thrust demanded from the powerplant;
• determining a power need for the engine based on the input indicative of thrust demanded from the powerplant;
• determining whether the power need is compatible with the second setting for the propeller rotational speed;
• when the power need is compatible with the second setting for the propeller rotational speed, modifying a command for at least one of fuel flow to the engine and oil flow to the propeller to govern the powerplant in accordance with the second setting for the propeller rotational speed;
• and
• when the power need is incompatible with the second setting for the propeller rotational speed, overriding the pilot request to change the propeller rotational speed from the first setting to the second setting by maintaining the first setting for the propeller rotational speed despite the pilot request to change the propeller rotational speed from the first setting to the second setting;
• wherein:
• the second setting for the propeller rotational speed is lower than a maximum propeller rotational speed;
• the engine is a first engine and the variable-pitch propeller is a first variable-pitch propeller;
• the aircraft has a twin engine configuration including a second engine coupled to a second variable-pitch propeller;
• and
• the controller is configured for:
• when a failure of the second engine is detected while the powerplant is governed in accordance with the second setting for the propeller rotational speed, governing the powerplant in accordance with the maximum propeller rotational speed for the first variable-pitch propeller;
• and
• when the pilot selects take-off power through the power lever while the powerplant is governed in accordance with the second setting during cruise, causing, by a control system of the aircraft, the powerplant to be governed in accordance with the maximum propeller rotational speed for the first variable-pitch propeller.