Apparatus and associated methods relate to determining, based on a spatial extent of ice accretion, a maximum size of super-cooled droplets contained in an atmosphere and/or if an atmosphere contains super-cooled water droplets that equal and/or exceed a predetermined size. A testing region on an exterior surface of an aircraft is monitored for ice accretion by an ice detector. A boundary calculator determines a specific location to be tested within the testing region. The determined specific location corresponds to a calculated boundary that separates an ice-accretion region from an ice-free region if the atmosphere contains super-cooled water droplets of no larger than the predetermined size. If the ice detector detects ice accretion at the determined specific location, an alert is generated. The alert can advantageously inform a pilot of the aircraft that the atmosphere contains super-cooled water droplets that equal or exceed the predetermined size.

Apparatus and associated methods relate to determining, based on a spatial extent of ice accretion, a maximum size of super-cooled droplets contained in an atmosphere and/or if an atmosphere contains super-cooled water droplets that equal and/or exceed a predetermined size. A testing region on an exterior surface of an aircraft is monitored for ice accretion by an ice detector. A boundary calculator determines a specific location to be tested within the testing region. The determined specific location corresponds to a calculated boundary that separates an ice-accretion region from an ice-free region if the atmosphere contains super-cooled water droplets of no larger than the predetermined size. If the ice detector detects ice accretion at the determined specific location, an alert is generated. The alert can advantageously inform a pilot of the aircraft that the atmosphere contains super-cooled water droplets that equal or exceed the predetermined size.

Apparatus and associated methods relate to determining, based on a spatial extent of ice accretion, whether an atmosphere contains super-cooled water droplets that equal and/or exceed a predetermined size. A convex-shaped housing is mounted to an aircraft and exposed to an airstream. The convex-shaped housing has a testing region that is monitored for ice accretion by an ice detector. A boundary locator determines a specific location to be tested within the testing region. The determined specific location corresponds to a calculated boundary that separates an ice-accretion region from an ice-free region if the atmosphere contains super-cooled water droplets up to the predetermined size. If the ice detector detects ice accretion at the determined specific location, an alert is generated. The alert can advantageously inform a pilot of an atmosphere containing super-cooled water droplets that equal or exceed the predetermined size.

Apparatus and associated methods relate to determining, based on a spatial extent of ice accretion, whether an atmosphere contains super-cooled water droplets that equal and/or exceed a predetermined size. A convex-shaped housing is mounted to an aircraft and exposed to an airstream. The convex-shaped housing has a testing region that is monitored for ice accretion by an ice detector. A boundary locator determines a specific location to be tested within the testing region. The determined specific location corresponds to a calculated boundary that separates an ice-accretion region from an ice-free region if the atmosphere contains super-cooled water droplets up to the predetermined size. If the ice detector detects ice accretion at the determined specific location, an alert is generated. The alert can advantageously inform a pilot of an atmosphere containing super-cooled water droplets that equal or exceed the predetermined size.

An ice protection system for an aircraft includes one or more heaters configured to be coupled to a surface of a wing of the aircraft. The ice protection system also includes a controller configured to, in response to a first determination indicating presence of an icing condition, determine a setpoint temperature for a first location of an outer surface of the wing configured to be heated by a heater of the one or more heaters. The controller is also configured to control power provided to the heater based on the setpoint temperature. The setpoint temperature for the first location is determined to cause a second location of the outer surface of the wing, which is heated by the heater and is located at a particular distance from the first location, to remain above a threshold temperature based on a projected temperature profile of the outer surface heated by the heater.

An ice protection system for an aircraft includes one or more heaters configured to be coupled to a surface of a wing of the aircraft. The ice protection system also includes a controller configured to, in response to a first determination indicating presence of an icing condition, determine a setpoint temperature for a first location of an outer surface of the wing configured to be heated by a heater of the one or more heaters. The controller is also configured to control power provided to the heater based on the setpoint temperature. The setpoint temperature for the first location is determined to cause a second location of the outer surface of the wing, which is heated by the heater and is located at a particular distance from the first location, to remain above a threshold temperature based on a projected temperature profile of the outer surface heated by the heater.

A system includes a plurality of sensors along a surface of an airfoil operable to measure a first set of ice thickness values at a first time and a second set of ice thickness values at a second time. The system further includes a processor configured to determine a first plurality of lift calculation variables and a second plurality of lift calculation variables. The processor also generates a threshold angle of attack value and updates the threshold angle of attack value at the second time, based on one or more differences between the first and second sets of ice thickness values and the first and second plurality of lift calculation variables. The processor is further configured to send, to a display, based on the updated threshold angle of attack, one or more changes to flight data to adjust the actual angle of attack of the airfoil.

A system includes a plurality of sensors along a surface of an airfoil operable to measure a first set of ice thickness values at a first time and a second set of ice thickness values at a second time. The system further includes a processor configured to determine a first plurality of lift calculation variables and a second plurality of lift calculation variables. The processor also generates a threshold angle of attack value and updates the threshold angle of attack value at the second time, based on one or more differences between the first and second sets of ice thickness values and the first and second plurality of lift calculation variables. The processor is further configured to send, to a display, based on the updated threshold angle of attack, one or more changes to flight data to adjust the actual angle of attack of the airfoil.

An airfoil (100) comprises a skin (110), comprising an external surface (112) and an internal surface (114), opposite the external surface (112). The skin (110) is magnetically and electrically conductive. The airfoil (100) also comprises an interior space (108), formed by the skin (110). The internal surface (114) faces the interior space (108). The airfoil (100) additionally comprises a leading edge (106) along the external surface (112). The airfoil (100) further comprises a hybrid acoustic induction-heating system (102), configured to impede formation of ice on the external surface (112). The hybrid acoustic induction-heating system (102) comprises an induction coil (130) within the interior space (108). At least a portion (136) of the induction coil (130) is sufficiently close to the internal surface (114) to produce an eddy current (180) in the skin (110) when an alternating electrical current (134) is flowing in the induction coil (130). The hybrid acoustic induction-heating system (102) also comprises at least one magnet (140) within the interior space (108). At least the one magnet (140) is configured to produce a steady-state magnetic field (182) within the skin (110).

An aircraft ice detection system is configured to determine a condition of a cloud and includes a radar system, a lidar system, optics and a dichroic filter. The radar system is configured to project quasi-optical radiation to the cloud and receive reflected quasi-optical radiation from the cloud. The lidar system is configured to project optical radiation to the cloud and receive reflected optical radiation from the cloud. The optics are configured to direct the quasi-optical radiation and the optical radiation to the cloud and receive the reflected quasi-optical radiation and the reflected optical radiation from the cloud. The dichroic filter is configured to direct the quasi-optical radiation from the radar system to the optics, direct the optical radiation from the lidar system to the optics, direct the reflected quasi-optical radiation from the optics to the radar system and direct the reflected optical radiation from the optics to the lidar system.