There is provided a system and a method for operating a multi-engine rotorcraft. When the rotorcraft is cruising in an asymmetric operating regime (AOR) at least one engine is an active engine and is operated in an active mode to provide motive power to the rotorcraft and at least one second engine is a standby engine and is operated in a standby mode to provide substantially no motive power to the rotorcraft, at least one of a power level of the at least one second engine is increased and at least one variable geometry mechanism of the at least one second engine is moved to shed any ice accumulation on the at least one second engine.

An ice protection system adapted to protect at least one ice-susceptible flight surface of an aircraft includes a mechanical ice protection device attached to the flight surface. A controller controls a power source that causes the mechanical ice protection device to change in shape and, thereby, change an aerodynamic characteristic of the flight surface. This change in shape happens only when the current thickness of ice on the surface exceeds a minimum thickness.

An ice protection system adapted to protect at least one ice-susceptible flight surface of an aircraft includes a mechanical ice protection device attached to the flight surface. A controller controls a power source that causes the mechanical ice protection device to change in shape and, thereby, change an aerodynamic characteristic of the flight surface. This change in shape happens only when the current thickness of ice on the surface exceeds a minimum thickness.

A method for de-icing or anti-icing an aircraft portion having at least one piezoelectric element fastened on the inner face of the aircraft portion includes, during a design phase of the aircraft portion, placing the piezoelectric element on an area of the aircraft portion to determine frequencies of resonance and increased dynamic coupling, and during the de-icing or anti-icing of the aircraft portion, the same piezoelectric element is excited according to the natural frequencies of the area.

A method for de-icing or anti-icing an aircraft portion having at least one piezoelectric element fastened on the inner face of the aircraft portion includes, during a design phase of the aircraft portion, placing the piezoelectric element on an area of the aircraft portion to determine frequencies of resonance and increased dynamic coupling, and during the de-icing or anti-icing of the aircraft portion, the same piezoelectric element is excited according to the natural frequencies of the area.

A system and a method include at least one control unit that determines a de-icing time for an aircraft within a de-icing area of an airport, predicts a de-icing time for an aircraft within a de-icing area of an airport, schedules de-icing times for a plurality of aircraft within a de-icing area of an airport, and/or predicts demand for future de-icing operations of aircraft within a de-icing area of an airport.

A method of monitoring an ice protection system of a rotorcraft or an aircraft includes applying heat to rotating blades of the rotorcraft or the aircraft according to a heater duty cycle and determining an anticipated ice shed time for ice to shed from the rotating blades. Torque of the rotating blades is sensed, and an actual ice shed time for ice to shed from the rotating blades is determined based on the sensed torque. A status of the ice protection system is determined based on the anticipated ice shed time and the actual ice shed time, and the status of the ice protection system is output for consumption by a consuming system.

On an aircraft, a multi-mode power generator is operated in a variable voltage mode to power an electric Wng Ice Prevention System (eWIPS), and is operated in a fixed voltage mode to provide backup power. When atmospheric conditions are conducive to the formation of ice (and main generators are operative), the multi-mode power generator is operated in variable voltage mode to power the eWIPS with a first or second variable voltage. The first variable voltage, the value of which depends on atmospheric conditions, is for anti-ice operation. The second variable voltage, which can be the maximum output voltage, is for de-ice operation. Transitions between different variable voltage levels are not instantaneous which eliminates fatigue damage due to transients. If a main generator fails (or when atmospheric conditions are not conducive to the formation of ice), the multi-mode power generator is operated in fixed voltage mode to provide backup power.

A number of devices are provided for detecting presence of ice in an airstream. In some examples such device includes a housing defining a first chamber and a second chamber, and a partition wall separating the first chamber and the second chamber. The first chamber has at least one inlet opening on a front housing wall facing the airstream, and at least one outlet opening, smaller than the at least one inlet opening. The second chamber is configured for being operatively coupled to at least one electromagnetic (EM) system that is configured for transmitting EM energy to the first chamber at least via the partition wall, which is transparent and/or translucent with respect to the EM energy, the EM energy being configured for melting ice that can accrete with respect to the inlet opening. The device is configured for being operatively coupled to at least one air pressure sensor in fluid communication with the first chamber for detecting at least pressure changes in the first chamber responsive to ice accretion on the inlet opening.

A number of devices are provided for detecting presence of ice in an airstream. In some examples such device includes a housing defining a first chamber and a second chamber, and a partition wall separating the first chamber and the second chamber. The first chamber has at least one inlet opening on a front housing wall facing the airstream, and at least one outlet opening, smaller than the at least one inlet opening. The second chamber is configured for being operatively coupled to at least one electromagnetic (EM) system that is configured for transmitting EM energy to the first chamber at least via the partition wall, which is transparent and/or translucent with respect to the EM energy, the EM energy being configured for melting ice that can accrete with respect to the inlet opening. The device is configured for being operatively coupled to at least one air pressure sensor in fluid communication with the first chamber for detecting at least pressure changes in the first chamber responsive to ice accretion on the inlet opening.