Patent Description:
Aircraft are used to transport passengers and cargo between various locations. Various aircraft include icing detectors that are used to determine icing conditions on various portions of the aircraft, such as portions of an engine, wings, and the like. In response to detection of icing conditions, ice protection systems are activated to remove or otherwise reduce the ice on the portions of the aircraft.

Certain regulations, such as promulgated by the United States Federal Aviation Administration (FAA), define atmospheric envelopes in which icing conditions are considered for aircraft design and certification. Accumulation of ice on certain surfaces, such as aircraft wings and engine inlets, may affect performance of the aircraft. Icing conditions can exist in different forms, such as supercooled liquid water, ice crystals, or a mixture of the two.

Ice accumulation on a leading edge of a wing can impact lift and drag characteristics, while ice accumulation on an engine inlet or ingestion of ice crystals into the engine can reduce thrust. Additionally, ice accretion on air data probes can cause erroneous air data measurements. As such, real-time detection of icing conditions is used to ensure safe and efficient operation of an aircraft.

The distinct icing types have different and unique effects on an aircraft, which can pose a risk to transport category commercial aircraft at all temperatures and conditions within FAA icing regulations, for example but not limited to, <NUM> CFR Part <NUM>, Appendix C, O and <NUM> CFR Part <NUM> Appendix D icing envelopes. Known aircraft typically use an ice accretion sensor that includes a probe designed to collect supercooled water droplets on the probe surface. However, the probe is typically unable to detect ice crystals within the Appendix D icing envelope.

<CIT>, in accordance with its abstract, states a system includes a device having a first surface configured to be exposed to airflow about an exterior of an aircraft, the device including a first self-compensating heater configured to heat the first surface, a first current monitor configured to sense a first measurement value representing electrical current flow through the first self-compensating heater, one or more processors, and computer-readable memory encoded with instructions that, when executed by the one or more processors, cause the system to receive aircraft flight condition data and produce an icing condition signal based upon the first measurement value and the aircraft flight condition data.

<CIT>, in accordance with its abstract, states an anti-ice system for an aircraft. The system includes one or more sensors that are configured to generate data indicative of one or more of the size, shape, density and type of air borne particles in the vicinity of the aircraft. The one or more sensors are coupled to a data conditioner that is configured to prepare the data for processing. The data conditioner is coupled to a reasoner that is configured to determine from the data, the severity of an icing threat to an airframe, at least one engine and at least one air data probe. One or more controllers are coupled to the reasoner. The one or more controllers automatically operate an anti-icing mechanism for at least one of the at least one engine, the airframe, and the at least one air data probe depending on the icing threats determined by the reasoner.

<CIT>, in accordance with its abstract, states a system for detecting the presence of ice crystals in a cloud comprising two thin walled semicylinder-shaped sensors, one having a concave inner surface and oriented longitudinally in a leading edge of an airfoil and the other having a convex outer surface being oriented longitudinally in the leading edge of the airfoil so that cloud water flows towards and into contact with the convex outer surface; a temperature controlling arrangement for heating the two sensors and maintaining them at a substantially constant temperature; and a comparison arrangement for finding a difference between (i) a power to maintain the temperature of the first sensor at its substantially constant temperature (ii) a power to maintain the temperature of the second sensor at its substantially constant temperature; and comparing the difference of the powers to a threshold value for evidencing the presence or predetermined amount of ice in the cloud water.

A need exists for an icing detection system and method that is able to distinguish between different types of icing conditions, such as supercooled water and ice crystals. Further, a need exists for a system and a method for detecting aircraft icing in various forms, and operating deicers in response thereto.

With those needs in mind, according to a first aspect, a system comprising a first icing detector, a second icing detector and a control unit is provided, as defined in claim <NUM>. Further, according to a second aspect, there is provided an aircraft comprising the system of the first aspect, as defined in claim <NUM>. Further still, according to a third aspect, there is provided a method as defined in claim <NUM>.

The present disclosure provide systems and methods for detecting aircraft icing, in various forms, and distinguishing between different icing conditions. The systems and methods include first and second icing detectors in communication with a control unit, which is configured to differentiate between supercooled liquid water and ice crystal icing conditions. The control unit is further configured to output signals to airframe and engine ice protection systems.

In contrast to known ice detection systems, examples of the present disclosure are configured to identify and differentiate between both glaciated ice crystals and supercooled liquid water, and thereby provide a health check for an aircraft, including various systems, engines, and the like. Further, the systems and methods described herein are able to detect different phases of water. As such, examples of the present disclosure are independent of drop size or temperature, and can therefore function in any icing conditions (for example, Appendix C, Appendix O, or Appendix D).

Also, the systems and methods described herein increase flight deck crew situational awareness, in contrast to known systems, which rely on memory items and checklists. Additionally, the systems and methods described herein lead to reduced power and/or fuel consumption due to optimized activation of the ice protection systems.

<FIG> illustrates a schematic block diagram of a system <NUM> for deicing one or more portions of an aircraft <NUM>, according to the present disclosure. The system <NUM> includes a first icing detector <NUM> and a second icing detector <NUM>. A control unit <NUM> is in communication with the first icing detector <NUM> and the second icing detector <NUM>, such as through one or more wired or wireless connections. The control unit <NUM> is further in communication with a first deicer <NUM> and a second deicer <NUM>, such as through one or more wired or wireless connections. In at least one example, the control unit <NUM> is also in communication with a user interface <NUM>, such as can be part of a computer workstation, a flight deck computer, or the like. For example, the user interface <NUM> can be located in a cockpit or flight deck of the aircraft <NUM>.

The deicers <NUM> and <NUM> can be any types of devices, systems, or the like configured to deice portions of an aircraft. Examples of the deicers <NUM> and <NUM> include anti-ice systems, ice prevention systems, deicing devices and systems, and/or the like.

The first icing detector <NUM> includes one or more probes, sensors, or the like that are configured to detect a first icing condition. The first icing detector <NUM> is an icing conditions detector that is configured to detect both ice water content and liquid water content. While such an icing conditions detector is configured to detect ice water content and liquid water content, the icing conditions detector is unable to differentiate between ice water content and liquid water content.

The second icing detector <NUM> includes one or more probes, sensors, or the like that are configured to detect a second icing condition, which may differ from the first icing condition. The second icing detector <NUM> is a magnetostrictive ice detector, which can detect liquid water content, but not ice water content. Ice accretion on a magnetostrictive ice detector builds and sheds in cycles. Typically, when a magnetostrictive ice detector is used, an engine anti-ice operation is performed before a wing anti-ice operation.

As noted, the control unit <NUM> is in communication with one or more deicers that are configured to deice one or more portions of the aircraft <NUM>. For example, the first deicer <NUM> is configured to deice one or more first portions of the aircraft <NUM>. The first deicer <NUM> is, or is part of, an ice protection system. In at least one example, the first deicer <NUM> is configured to deice one or more portions of an engine of the aircraft <NUM>. The first deicer <NUM> can include one or more heaters, heating coils, heating mats, pneumatic heaters, hot air blowers, and/or the like.

The second deicer <NUM> is configured to deicer one or more second portions of the aircraft <NUM>. The second deicer <NUM> is or is part of an ice protection system. In at least one example, the second deicer <NUM> is configured to deice one or more portions of a wing of the aircraft <NUM>. The second deicer <NUM> can include one or more heaters, heating coils, heating mats, pneumatic heaters, hot air blowers, and/or the like.

Optionally, the first deicer <NUM> is configured to deice or more portions of a wing of the aircraft <NUM>, and the second deicer <NUM> is configured to deice or more portions of the engine of the aircraft <NUM>. Also, optionally, the control unit <NUM> can be in communication with more or less deicers than shown. For example, the control unit <NUM> can be in communication with only the first deicer <NUM> or the second deicer <NUM>. As another example, the control unit <NUM> can be in communication with three or more deicers, each of which is configured to deice a different portion of the aircraft <NUM>.

As noted, the user interface <NUM> can be part of a computer workstation, a flight computer, and/or the like within the aircraft <NUM>. The user interface <NUM> includes a display <NUM>, such as an electronic monitor, screen, television, or the like, and a speaker <NUM> (for example, an audio speaker, loudspeaker, and/or the like). Optionally, the user interface <NUM> may include only one of the display <NUM> or the speaker <NUM>.

In operation, the first icing detector <NUM> is configured to detect the first icing condition and the second icing detector <NUM> is configured to detect the second icing condition. In response to detecting the first icing condition, the first icing detector <NUM> outputs a first icing signal <NUM> indicative of the first icing condition. Similarly, in response to detecting the second icing condition, the second icing detector <NUM> outputs a second icing signal <NUM> indicative of the second icing condition. The control unit <NUM> receives the first icing signal <NUM> and the second icing signal <NUM> from the first icing detector <NUM> and the second icing detector <NUM>, respectively. As described herein, the control unit <NUM> differentiates between presence of liquid water content (such as supercooled liquid water) and ice crystal formation (for example, ice crystal icing) based on receiving one or both of the first icing signal <NUM> and the second icing signal <NUM>. In at least one example, in response, the control unit <NUM> operates the first deicer <NUM> and the second deicer <NUM> in response to receiving one or both of the first icing signal <NUM> and/or the second icing signal <NUM>. In at least one example, the control unit <NUM> also outputs one or more information signals <NUM> to the user interface <NUM>. The information signals <NUM> are indicative of information based on the icing conditions. Such information can be shown on the display <NUM> and/or broadcast through the speaker <NUM>. Optionally, the control unit <NUM> can differentiate between icing conditions but not automatically operate one or more deicers in response thereto.

In response to the control unit <NUM> receiving the first icing signal <NUM> indicative of the first icing condition from the first icing detector <NUM> (such as an icing conditions detector that is configured to detect both ice water content and liquid water content), and the second icing signal <NUM> indicative of the second icing condition from the second icing detector <NUM> (a magnetostrictive ice detector that is only able to detect liquid water content), the control unit <NUM> determines the presence of supercooled liquid water and potentially ice crystals on one or more surfaces of the aircraft <NUM>. Accordingly, the control unit <NUM> can then automatically operate the first deicer <NUM>, such as to remove ice from one or more portions of an engine, and the second deicer <NUM>, such as to remove ice from one or more surfaces of a wing. In this manner, the system <NUM> reduces overuse (and therefore energy consumption) of the deicers, as both the first icing signal <NUM> and the second icing signal <NUM> are received in order to activate both the first deicer <NUM> and the second deicer <NUM>. The control unit <NUM> can further output one or more information signals <NUM> indicating potential for ice building on edges of windscreens and wiper blades, which can be shown on the display <NUM> and/or broadcast via the speaker <NUM>.

In at least one example, in response to the receiving both the first icing signal <NUM> and the second icing signal <NUM>, the control unit <NUM> automatically operates the first deicer <NUM> to remove, prevent, and/or otherwise reduce icing in relation to an engine of the aircraft <NUM>. The control unit <NUM> can then activate the second deicer <NUM> based on the cycles of the first deicer <NUM>. As a non-limiting example, the first deicer <NUM> can be activated after two detection cycles, and the second deicer <NUM> can be activated after eight additional detection cycles. In other examples, the first deicer <NUM> can be activated in fewer or more than two detections cycles, and the second deicer <NUM> can be activated in fewer or more than eight additional detection cycles.

In response to the control unit <NUM> receiving the first icing signal <NUM> indicative of the first icing condition, but not the second icing signal <NUM> indicative of the second icing condition (that is, the control unit <NUM> only receives the first icing signal <NUM>), the control unit <NUM> determines the presence of ice crystals. For example, if liquid water content was present, then the control unit <NUM> would also receive the second icing signal <NUM> from the second icing detector <NUM>. Because the first icing detector <NUM> is able to detect both ice water content and liquid water content, reception of the first icing signal <NUM> indicative of the first icing condition necessarily means that ice water content is present, but not liquid water content. In this manner, the control unit <NUM> can differentiate between ice water content and liquid water content through analysis of the first icing signal <NUM> and the second icing signal <NUM>. In particular, if both the first icing signal <NUM> and the second icing signal <NUM> are received, the control unit <NUM> determines that both supercooled liquid water content and potentially ice crystals are present on one or more portions of the aircraft <NUM>. If, however, only the first icing signal <NUM> is received, but not the second icing signal <NUM>, the control unit <NUM> determines that ice crystals are present on or more portions of the aircraft <NUM>. In either scenario, the control unit <NUM> automatically operates one or both of the first deicer <NUM> or the second deicer <NUM> to remove, prevent, or otherwise reduce potential ice formation on one or more portions of the aircraft <NUM>. The control unit <NUM> can further output the one or more information signals <NUM> to the user interface <NUM>, in order to display and/or broadcast information regarding activation of the one or more deicers, for example. The information signals <NUM> can also include information regarding effects in relation to various portions of the aircraft <NUM>.

In response to the control unit <NUM> receiving the second icing signal <NUM> from the second icing detector <NUM>, but not the first icing signal <NUM> from the first icing detector <NUM>, the control unit <NUM> determines an error condition, which may require maintenance. For example, the first icing detector <NUM> is configured to detect both ice water content and liquid water content, while the second icing detector <NUM> is configured to detect only liquid water content. By receiving the second icing signal <NUM> from the second icing detector indicating the presence of liquid water content, but not the first icing signal <NUM> which would otherwise also detect the presence of liquid water content, the control unit <NUM> determines a malfunction of one or both of the first icing detector <NUM> and/or the second icing detector <NUM>. In response, the control unit <NUM> outputs the one or more information signals <NUM> which include an alert message indicating the potential of an error.

As used herein, the term "control unit," "central processing unit," "CPU," "computer," or the like may include any processor-based or microprocessor-based system including systems using microcontrollers, reduced instruction set computers (RISC), application specific integrated circuits (ASICs), logic circuits, and any other circuit or processor including hardware, software, or a combination thereof capable of executing the functions described herein. Such are exemplary only, and are thus not intended to limit in any way the definition and/or meaning of such terms. For example, the control unit <NUM> may be or include one or more processors that are configured to control operation, as described herein.

The control unit <NUM> is configured to execute a set of instructions that are stored in one or more data storage units or elements (such as one or more memories), in order to process data. For example, the control unit <NUM> may include or be coupled to one or more memories. The data storage units may also store data or other information as desired or needed. The data storage units may be in the form of an information source or a physical memory element within a processing machine.

The set of instructions may include various commands that instruct the control unit <NUM> as a processing machine to perform specific operations such as the methods and processes of the various examples of the subject matter described herein. The set of instructions may be in the form of a software program. The software may be in various forms such as system software or application software. Further, the software may be in the form of a collection of separate programs, a program subset within a larger program, or a portion of a program. The software may also include modular programming in the form of object-oriented programming. The processing of input data by the processing machine may be in response to user commands, or in response to results of previous processing, or in response to a request made by another processing machine.

The diagrams of examples herein may illustrate one or more control or processing units, such as the control unit <NUM>. It is to be understood that the processing or control units may represent circuits, circuitry, or portions thereof that may be implemented as hardware with associated instructions (e.g., software stored on a tangible and (optionally, non-transitory) computer readable storage medium, such as a computer hard drive, ROM, RAM, or the like) that perform the operations described herein. The hardware may include state machine circuitry hardwired to perform the functions described herein. Optionally, the hardware may include electronic circuits that include and/or are connected to one or more logic-based devices, such as microprocessors, processors, controllers, or the like. Optionally, the control unit <NUM> may represent processing circuitry such as one or more of a field programmable gate array (FPGA), application specific integrated circuit (ASIC), microprocessor(s), and/or the like. The circuits in various examples may be configured to execute one or more algorithms to perform functions described herein. The one or more algorithms may include aspects of examples disclosed herein, whether or not expressly identified in a flowchart or a method.

<FIG> illustrates a flow chart of a method for deicing one or more portions of an aircraft, according to an example of the present disclosure. Referring to <FIG> and <FIG>, at <NUM>, the control unit <NUM> is communicatively coupled to the first icing detector <NUM> and the second icing detector <NUM>. At <NUM>, the control unit <NUM> determines if the first icing signal <NUM> indicative of the first icing condition is received. If the first icing signal <NUM> is received at <NUM>, the control unit <NUM> next determines at <NUM> if the second icing signal <NUM> indicative of the second icing condition is received. If the second icing signal is also received at <NUM>, the method proceeds to <NUM>, at which the control unit <NUM> determines that supercooled liquid water content and potential ice crystal icing is present on one or more surfaces of the aircraft <NUM>. At <NUM>, the control unit <NUM> then activates one or more deicers, such as the first deicer <NUM> and/or the second deicer <NUM>, in response thereto. Optionally and/or additionally, at <NUM>, instead of deicers being activated, the control unit <NUM> can trigger an internal engine function, such as raising idle speed.

If, however, the second icing signal <NUM> is not detected at <NUM>, the method proceeds to <NUM>, at which the control unit <NUM> determines the presence of ice crystal icing. At <NUM>, the control unit <NUM> then activates the one or more deicers, such as the first deicer <NUM> and/or the second deicer <NUM>, in response thereto. Optionally and/or additionally, at <NUM>, instead of deicers being activated, the control unit <NUM> can trigger an internal engine function, such as raising idle speed.

If, however, the first icing signal <NUM> is not received at <NUM>, the method proceeds to <NUM>, at which the control unit <NUM> determines if the second icing signal <NUM> has been received. If the first icing signal <NUM> is not received at <NUM> and the second icing signal <NUM> is not received at <NUM>, the control unit <NUM> determines that no icing conditions are present, and refrains from activating the deicers at <NUM>.

If, however, the first icing signal <NUM> is not received at <NUM>, but the second icing signal <NUM> is received at <NUM>, the control unit <NUM> determines an error condition at <NUM>. The error condition may be a scenario that requires maintenance, such as to check and potentially repair one or both of the ice detectors <NUM> and <NUM>. Accordingly, the method may then proceed from <NUM> to <NUM>, at which the control unit <NUM> outputs an information signal <NUM> indicating the error condition to the user interface <NUM>. The error condition can be shown on the display <NUM> and/or broadcast through the speaker <NUM>.

The method can also include message to individuals, such as pilots, regarding the operations described herein. The messages can be shown on a display and/or broadcast through a speaker.

<FIG> illustrates a perspective front view of the aircraft <NUM>, according to an example of the present disclosure. The aircraft <NUM> includes a propulsion system <NUM> that includes engines <NUM>, for example. In at least one example, one or more first deicers <NUM> (shown in <FIG>) are operatively coupled to one or more of the engines <NUM>. Optionally, the propulsion system <NUM> may include more engines <NUM> than shown. The engines <NUM> are carried by wings <NUM> of the aircraft <NUM>. In at least one example, one or more second deicers <NUM> (shown in <FIG>) are operatively coupled to one or both of the wings <NUM>.

In other embodiments, the engines <NUM> may be carried by a fuselage <NUM> and/or an empennage <NUM>. The empennage <NUM> may also support horizontal stabilizers <NUM> and a vertical stabilizer <NUM>. The fuselage <NUM> of the aircraft <NUM> defines an internal cabin <NUM>, which includes a flight deck or cockpit, one or more work sections (for example, galleys, personnel carry-on baggage areas, and the like), one or more passenger sections (for example, first class, business class, and coach sections), one or more lavatories, and/or the like. The user interface <NUM> shown in <FIG> is within the internal cabin <NUM>, such as within the flight deck.

<FIG> shows an example of an aircraft <NUM>. It is to be understood that the aircraft <NUM> can be sized, shaped, and configured differently than shown in <FIG>.

<FIG> illustrates a perspective lateral view of a nose <NUM> of the aircraft <NUM>, according to an example of the present disclosure. The first icing detector <NUM> and the second icing detector <NUM> can be located proximate to the nose <NUM>. For example, the first icing detector <NUM> and the second icing detector <NUM> can be disposed below a window <NUM> of the flight deck and above a front landing gear <NUM>. The first icing detector <NUM> and the second icing detector <NUM> can be on the same side of the aircraft <NUM>. Optionally, the first icing detector <NUM> can be on a first side of the aircraft <NUM>, and the second icing detector <NUM> can be on a second side of the aircraft <NUM>. Optionally, the first icing detector <NUM> and the second icing detector <NUM> can be at various other locations of the aircraft <NUM>, such as on a top of the fuselage, on one or more engines, one or more wings, and/or the like.

As described herein, examples of the present disclosure provide systems and methods that are able to distinguish between different types of icing conditions, such as supercooled water and ice crystals. Further, examples of the present disclosure provide systems and methods for detecting icing in various forms and operating deicers in response thereto.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described examples (and/or aspects thereof) can be used in combination with each other. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the various examples of the disclosure without departing from their scope. While the dimensions and types of materials described herein are intended to define the parameters of the various examples of the disclosure, the examples are by no means limiting and are exemplary examples. Many other examples will be apparent to those of skill in the art upon reviewing the above description. The scope of the various examples of the disclosure should, therefore, be determined with reference to the appended claims. In the appended claims and the detailed description herein, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein. " Moreover, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

Claim 1:
A system (<NUM>) comprising:
a first icing detector (<NUM>) configured to detect a first icing condition in relation to one or more portions of an aircraft (<NUM>), wherein the first icing detector (<NUM>) is an icing conditions detector configured to detect both ice water content and liquid water content, wherein the icing conditions detector is unable to differentiate between the ice water content and the liquid water content, and wherein the first icing detector (<NUM>) is configured to output a first icing signal (<NUM>) indicative of the first icing condition;
a second icing detector (<NUM>) configured to detect a second icing condition in relation to the one or more portions of the aircraft (<NUM>), wherein the second icing detector (<NUM>) is a magnetostrictive ice detector configured to detect the liquid water content only, and wherein the second icing detector (<NUM>) is configured to output a second icing signal (<NUM>) indicative of the second icing condition; and
a control unit (<NUM>) in communication with the first icing detector (<NUM>) and the second icing detector (<NUM>), wherein the control unit (<NUM>) is configured to receive the first icing signal (<NUM>) from the first icing detector (<NUM>) and the second icing signal (<NUM>) from the second icing detector (<NUM>), and wherein the control unit (<NUM>) is further configured to distinguish between presence of supercooled liquid water and ice crystal icing in response to receiving one or both of the first icing signal (<NUM>) or the second icing signal (<NUM>).