EP3478582A1

EP3478582A1 - Intuitive display of angle of attack guidance on aircraft attitude indicator

Info

Publication number: EP3478582A1
Application number: EP17819472.6A
Authority: EP
Inventors: Gary Watson
Original assignee: L3 Technologies Avionic Products
Current assignee: L3 Technologies Avionic Products
Priority date: 2016-06-29
Filing date: 2017-06-29
Publication date: 2019-05-08
Also published as: BR112018077334A2; WO2018002878A1; CA3029131A1

Abstract

An aircraft avionic system for use in an equipped aircraft includes a controller and a display. The controller provides output data to the display, with the output data producing visual images on the display. An angle of attack data source provides current angle of attack data for the equipped aircraft. The controller is responsive to the angle of attack data in order to provide the output data to drive the display to depict a direction of control needed to preclude a stall. The display of direction of control needed is graduated based on a current level of stall imminence. The stall imminence is a function of the angle of attack of the equipped aircraft.

Description

INTUITIVE DISPLAY OF ANGLE OF ATTACK GUIDANCE ON AIRCRAFT ATTITUDE

INDICATOR

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. provisional patent application Serial No.:

62/356,118, filed on June 29, 2016, the disclosure of which is hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention is directed to aircraft avionics systems, and more particularly to integrated angle of attack indicators.

BACKGROUND OF THE INVENTION

[0003] Currently, the display of angle of attack information is a separate physical unit or a

representation of that display on an electronic flight display. It may also be displayed as a "fast/slow" or "pitch limit indicator" with respect to set points on previous instruments.

Therefore, a pilot is required to look away from an avionics display that they may be currently following, for example, an attitude display, to find the angle of attack indicator.

SUMMARY OF THE INVENTION

[0004] While a pilot may be trained to locate and follow the indications and recommendations available in current angle of attack indicators, it is an added requirement on a pilot, especially in high workload situations, such as low altitude maneuvering in an airport traffic pattern

(especially during takeoff and landing).

[0005] The present invention provides an avionics system that displays a direction of control needed to preclude an aerodynamic stall. This angle of attack indication may be graduated such that as the stall point is approached, the angle of attack indication starts to appear, and as the stall becomes imminent, a higher level of urgency is provided. Such higher levels of urgency may include various levels of opacity, different colors, and different graphical indications. The changing opacity, color, and graphical indications may also be supplemented with changing aural indications.

[0006] According to an aspect of the present invention, an aircraft avionic system for use in an equipped aircraft includes a controller and a display. The controller provides output data to the display. The display produces visual images on the display as defined by the output data. An angle of attack data source provides current angle of attack data for the equipped aircraft. The controller, responsive to the angle of attack data, provides the output data to drive the display to depict a direction of control needed to preclude a stall. The display of direction of control needed is graduated based on a current level of stall imminence. The stall imminence is a function of the angle of attack of the equipped aircraft.

[0007] The graduated display of direction of control needed may comprise a plurality of

graphical indications that include varying levels of at least one of opacity, color saturation, and color selection. The level of opacity and color saturation are a function of stall imminence, such that the level of opacity and color saturation increases as the level of stall imminence increases. The level of stall imminence may increase with an increase in angle of attack of the equipped aircraft.

[0008] The color selection may be a function of stall imminence, such that a first color indicates a normal flight condition, a second color indicates the equipped aircraft is in an approaching aerodynamic stall condition, a third color indicates the equipped aircraft is in a closer to aerodynamic stall condition, and a fourth color indicates a closest point to aerodynamic stall condition.

[0009] A point approaching aerodynamic stall may occur when the angle of attack is above the first threshold. A point closer to aerodynamic stall may occur when the angle of attack is above the first threshold and above a second threshold. A point closest to aerodynamic stall may occur when the angle of attack is above the first and second thresholds and above a third threshold.

[0010] The plurality of graphical indications may also include varying levels of flashing such that the graphical indication flashes on and off in a manner sufficient to attract the attention of the pilot. Similar to color selection, the rate of flashing of the graphical indications may be a function of stall imminence, with the rate of flashing increasing as the equipped aircraft approaches ever closer to aerodynamic stall conditions. The graphical indications may begin flashing when a particular aerodynamic stall condition is reached.

[0011] The avionics system may also include graduated auditory indications of direction of control needed. The graduated auditory indications may be a function of stall imminence. A volume of the auditory indications may increase with an increase in angle of attack of the equipped aircraft. [0012] The equipped aircraft may be considered to be in normal flight when the angle of attack data indicates the angle of attack of the equipped vehicle is below the first threshold. During normal flight, the controller response to the angle of attack data may provide output data to drive the display to depict a graphical indication that indicates when the equipped aircraft is flown in a best lift/drag condition.

[0013] According to an aspect of the present invention, a method for graduating display of

direction of control needed to preclude a stall includes receiving angle of attack data from an angle of attack data source. The angle of attack data is compared to a plurality of thresholds. If the angle of attack is below a first threshold the aircraft is considered to be in normal flight conditions and optimal lift/drag evaluations maybe displayed in an attitude indication display. If the angle of attack is above the first threshold, but below a second threshold, the aircraft is considered to be in an approaching aerodynamic stall condition, and a direction of control needed will be graphically indicated in a first graphic displayed in the attitude indication display. In another step of the method, if the angle of attack is above the first and second thresholds, but below a third threshold, the aircraft is considered to be in a closer to aerodynamic stall condition, and a direction of control needed will be graphically indicated in a second graphic displayed in the attitude indication display. If the angle of attack is above the first, second, and third thresholds, the aircraft is considered to be in a closest to aerodynamic stall condition, and a direction of control needed will be graphically indicated in a third graphic displayed in the attitude indication display. The graphics may be incremental, with the second graphic more opaque than the first graphic, and the third graphic more opaque than the second graphic.

[0014] The direction of control needed graphics may include varying levels of at least one of opacity, color saturation, and color selection. The level of opacity and color saturation may be decided as a function of stall imminence, such that the level of opacity and color saturation increases as the level of stall imminence increases. The level of stall imminence may increase with an increase in angle of attack of the equipped aircraft. The color selection may also be a function of stall imminence, such that a first color indicates normal flight, a second color indicates the equipped aircraft is approaching aerodynamic stall, a third color indicates the equipped aircraft is closer to aerodynamic stall, and a fourth color indicates the equipped aircraft is at a closest point to aerodynamic stall. [0015] In parallel with the display of the direction of control needed graphics, graduated auditory indications of the direction of control needed may also be used. The graduated auditory indications may also be a function of stall imminence. A volume of the auditory indications may increase with an increase in angle of attack of the equipped aircraft.

[0016] These and other objects, advantages, purposes, and features of this invention will become apparent upon review of the following specification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a block diagram illustrating an avionics system for an equipped aircraft in

accordance with an embodiment of the present disclosure;

[0018] FIG. 2 is a graphical illustration of an attitude display in a normal flight display

condition;

[0019] FIG. 3 is a graphical illustration of the attitude display of FIG. 2 in an approaching

aerodynamic stall condition;

[0020] FIG. 4 is a graphical illustration of the attitude display of FIG. 2 in a closer to

aerodynamic stall condition;

[0021] FIG. 5 is a graphical illustration of the attitude display of FIG. 2 in a closest to

aerodynamic stall condition;

[0022] FIG. 6 is a graphical illustration of the attitude display of FIG. 2 in a best lift/drag

condition when in normal flight condition; and

[0023] FIG. 7 is a flow diagram of a method for graduating a display of direction of control needed to preclude a stall in accordance with an embodiment of the present disclosure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present disclosure will now be described with reference to the accompanying figures, wherein the numbered elements in the following written description correspond to like-numbered elements in the figures.

[0025] As discussed herein, exemplary embodiments may be used to intuitively, and in a

graduated fashion, display control guidance needed by a pilot to preclude an aerodynamic stall, especially in high workload situations such as low altitude maneuvering in an airport traffic pattern (e.g., takeoff and landing). As discussed herein, exemplary embodiments provide an avionics system that displays a direction of flight control needed to preclude an aerodynamic stall. This flight control guidance indication may be graduated such that as a stall point is approached, direction of control indications start to appear, and as the aerodynamic stall becomes imminent, a higher level of urgency is provided. Such higher levels of urgency may be indicated with various levels of opacity, different colors, and different graphical selections. As also discussed herein, the changing opacity, colors, and graphical selections may also be

supplemented with changing aural indications.

[0026] As discussed herein, an aerodynamic stall point or critical angle of attack is that point where the angle of attack is high enough an airplane's wing may lose lift and stall. Once a particular aircraft's stall point is determined, various points approaching the stall point may also be identified. These points may also be determined over a range of aircraft conditions (airspeed, flap position, etc.). Therefore, as discussed herein, with known stall points and additional angle of attack values that are identified as approaching the stall point, a current angle of attack value may be evaluated.

[0027] An intuitive and graduated angle of attack indication embodiment, as illustrated in Figure

1, includes an angle of attack data source 102 that supplies angle of attack data to a controller 106. The controller 104 is agnostic to the source of the angle of attack data. Angle of attack data sources may include any known or anticipated angle of attack data source. Examples include angle of attack transducers or vanes, and angle of attack sensors. Regardless of the source, angle of attack data may comprise merely an angle value. The angle of attack data received from the angle of attack data source 102 is compared to a plurality of thresholds that are set as a function of current flight information data 104. Examples include airspeed and flap position. Setting the thresholds as a function of current flight information of the equipped aircraft allows for changing aerodynamic stall conditions as flight conditions change.

[0028] As discussed herein, the received angle of attack data is compared to threshold levels by the controller 106 and resultant angle of attack or direction of control guidance indications with respect to the equipped aircraft's proximity to aerodynamic stall conditions are displayed on a display 108. For example, control guidance may include an indication that the aircraft's pitch needs to be lowered to lower the current angle of attack, with the type of indication graduated, as discussed herein. [0029] In one aspect of the present invention, the display 108 is an attitude display, such as illustrated in Figure 2. While any number of graduated levels of imminent aerodynamic stall indication may be used, in an aspect of the present invention, four graduated levels of aerodynamic stall immanency are used. They are "normal flight" condition, "approaching aerodynamic stall" condition, "closer to aerodynamic stall" condition, and a "closest to aerodynamic stall" condition. While other descriptors may be used, the exemplary descriptors "approaching," "closer," and "closest," allow comparison and an intuitive and graduated display of a direction of flight control needed (e.g., a downward pitch) to preclude an aerodynamic stall of an aircraft. Obviously, the closer an equipped aircraft is to aerodynamic stall, the more urgent the need for the pilot to be informed of the condition and be provided the direction of control guidance needed to preclude the aerodynamic stall.

[0030] Therefore, as illustrated in Figure 3, when the controller 106 determines that a current angle of attack data value is above a first threshold value, but below a second threshold value, an "approaching aerodynamic stall" condition exists, and a corresponding direction of control indicator 302a, illustrated in Figure 3, is displayed. The depicted direction of control 302a for the approaching aerodynamic stall condition is a least intrusive indication added to the display 108. As illustrated in Figure 3, the depicted direction of control 302a indicates the equipped aircraft needs to be pitched down so that its current angle of attack decreases.

[0031] As illustrated in Figure 4, when the controller 106 determines that the current angle of attack data value is above the first threshold value and a second threshold value, but below a third threshold value, a "closer to aerodynamic stall" condition exists, and a corresponding direction of control indicator 302b, illustrated in Figure 4, is displayed. The depicted direction of control 302b for the closer to aerodynamic stall condition, is a more intrusive indication to pitch the aircraft down than the direction of control 302a depicted in Figure 3. In an aspect of the present invention, the direction of control 302b depicted in Figure 4 may comprise a different color, a different color saturation, and/or a background pattern, from the direction of control 302a depicted in Figure 3. While changing colors, color saturations, and background patterns, as discussed herein, may be used, other graphical depictions may also be used. For example, different geometrical shapes may be used.

[0032] As illustrated in Figure 5, when the controller 106 determines that the current angle of attack data value is above the first, second, and third threshold values, a "closest to aerodynamic stall" condition exists, and a corresponding direction of control indicator 302c, illustrated in Figure 5, is displayed. The depicted direction of control 302c for the closest to aerodynamic stall condition, is a much more visually intrusive indication to pitch the aircraft down than the previous indicator depictions 302b, 302a. Similar to the direction of control indicator 302b, the direction of control indicator 302c may also comprise a different color, a different color saturation, or a different background pattern as compared to the lower level direction of control indicators 302b, 302a.

[0033] In a further aspect of the present invention, illustrated in Figure 6, when the controller

106 determines that the current angle of attack data value is below the first threshold, a lift/drag ratio indicator 302d may be displayed when the controller 106 determines that a current determined lift/drag ratio during normal flight conditions is at an optimal level.

[0034] While changing colors, color saturations, and background patterns, as discussed herein, may be used, other graphical depictions may also be used. For example, different geometrical shapes may be used. In a further aspect of the present invention, auditory indicators may also be used. Examples include simple buzzers or bells, with varying volumes and degrees of attention catching qualities. The above-mentioned auditory indicators may also include verbal guidance and/or warning announcements.

[0035] Figure 7 is a flow diagram illustrating the steps to a method for graduating a display of direction of control needed to preclude an aerodynamic stall. As illustrated in Figure 7, in step 702, angle of attack data is received from an angle of attack source. As discussed herein, the angle of attack data may come from any angle of attack data source. In step 704 of Figure 7, the received angle of attack data is compared to threshold values. As also discussed herein, the threshold values are set as a function of the equipped aircraft's current flight conditions and related flight data.

[0036] In step 706 of Figure 7, if the angle of attack value is above a third threshold value, the equipped aircraft is considered to be in a "closest to aerodynamic stall" condition. When the angle of attack value is above the third threshold value, the process flow will continue to step 708 of Figure 7, and an aircraft condition will be set to "closest to aerodynamic stall." As illustrated in Figure 5, a corresponding direction of control (e.g., pitch control) needed for the "closest to aerodynamic stall" condition will be graphically indicated in a third graphic 302c displayed in the display 108. The third threshold value is greater than either of a second threshold value and a first threshold value.

[0037] In step 710 of Figure 7, if the angle of attack value is above the first and second threshold values and below the third threshold value, the equipped aircraft is considered to be in a "closer to aerodynamic stall" condition. When the angle of attack value is above the first and second threshold values and below the third threshold value, the process flow will continue to step 712 of Figure 7, and an aircraft condition will be set to "closer to aerodynamic stall." As illustrated in Figure 4, a corresponding direction of control (e.g., pitch control) needed for the "closer to aerodynamic stall" condition will be graphically indicated in a second graphic 302b displayed in the display 108.

[0038] In step 714 of Figure 7, if the angle of attack value is above the first threshold and below the second threshold, the equipped aircraft is considered to be in an "approaching aerodynamic stall" condition. When the angle of attack value is above the first threshold and below the second threshold value, the process flow will continue to step 716 of Figure 7, and an aircraft condition will be set to "approaching aerodynamic stall." As illustrated in Figure 3, a corresponding direction of control (e.g., pitch control) needed for the "approaching aerodynamic stall" condition will be graphically indicated in a first graphic 302a displayed in the display 108.

[0039] In step 718 of Figure 7, if the angle of attack value is below a first threshold, the

equipped aircraft is considered to be in a "normal flight" condition. As discussed herein, normal flight conditions, as illustrated in Figures 2 and 6, may include the absence of direction of control indicators 302, or the inclusion of a lift/drag optimal flight condition indicator 302d.

[0040] As discussed herein, the graphics may be incremental, with the second graphic more opaque than the first graphic, and the third graphic more opaque than the second graphic.

Alternatively, the first, second, and third graphics may be different colors, or different geometrical objects.

[0041] Changes and modifications in the specifically described embodiments can be carried out without departing from the principles of the present invention, which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents.

Claims

CLAIMS The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An aircraft avionic system for use in an equipped aircraft, said system comprising:

a controller and a display, said controller providing output data to said display, said output data producing visual images on said display;

an angle of attack data source providing current angle of attack data for the equipped aircraft; and

said controller responsive to said angle of attack data in order to provide said output data to drive said display to depict a direction of control needed to preclude a stall, wherein said display of direction of control is graduated based on a current level of stall imminence, wherein said stall imminence is a function of the angle of attack of the equipped aircraft.

2. The system as claimed in Claim 1 , wherein said graduated display of direction of control needed comprises a plurality of graphical indications comprising varying levels of at least one of opacity, color saturation, and color selection.

3. The system as claimed in Claim 2, wherein the level of opacity and color saturation are a function of stall imminence, such that the level of opacity and color saturation increases as the level of stall imminence increases, and wherein the level of stall imminence increases with an increase in angle of attack of the equipped aircraft.

4. The system as claimed in Claim 2, wherein the color selection is a function of stall imminence, such that a first color indicates normal flight, a second color indicates the equipped aircraft is approaching aerodynamic stall, a third color indicates the equipped aircraft is closer to aerodynamic stall, and a fourth color indicates the equipped aircraft is a closest point to aerodynamic stall.

5. The system as claimed in Claim 4, wherein a point approaching aerodynamic stall occurs when the angle of attack is above a first threshold, wherein a point closer to aerodynamic stall occurs when the angle of attack is above the first threshold and above a second threshold, and wherein a point closest to aerodynamic stall occurs when the angle of attack is above the first and second thresholds, and above a third threshold.

6. The system of Claim 5, wherein the equipped aircraft is in normal flight when the angle of attack data indicates the angle of attack of the equipped vehicle is below the first threshold.

7. The system as claimed in Claim 6, wherein during normal flight, said controller response to said angle of attack data provides output data to drive said display to depict a graphical display that indicates when the equipped aircraft is flown in a best lift/drag condition.

8. The system as claimed in any of Claims 1-7 further comprising graduated auditory indications of direction of control needed, wherein the graduated auditory indications are a function of stall imminence, wherein a volume of the auditory indications increases with an increase in angle of attack of the equipped aircraft.

9. The system as claimed in any of Claims 1-7, wherein said angle of attack data source is an angle of attack sensor.

10. A method for graduating display of direction of control needed to preclude a stall in an avionics equipped aircraft, the method comprises:

receiving angle of attack data from an angle of attack data source;

comparing the received angle of attack data to a plurality of thresholds;

selecting a normal flight condition if the angle of attack is below a first threshold, wherein a direction of control needed graphic displayed in an attitude display in the equipped aircraft is transparent;

selecting an "approaching aerodynamic stall" condition and graphically indicating a corresponding direction of control needed in a first graphic displayed in the attitude display when the angle of attack is above the first threshold but below a second threshold; selecting a "closer to aerodynamic stall" condition, and graphically indicating a corresponding direction of control needed in a second graphic displayed in the attitude display, when the angle of attack is above the first and second thresholds but below a third threshold; and selecting a "closest to aerodynamic stall" condition and graphically indicating a corresponding direction of control needed in a third graphic displayed in the attitude display when the angle of attack is above the first, second, and third thresholds.

11. The method as claimed in Claim 10, wherein displaying the first, second, and third graphics comprises displaying a plurality of graphical indications comprising varying levels of at least one of opacity, color saturation, and color selection.

12. The method as claimed in Claim 11, wherein the level of opacity and color saturation are a function of stall imminence, such that the level of opacity and color saturation increases as the level of stall imminence increases, and wherein the level of stall imminence increases with an increase in angle of attack of the equipped aircraft.

13. The method as claimed in Claim 11, wherein the color selection is a function of stall imminence, such that a first color indicates normal flight, a second color indicates the equipped aircraft is approaching aerodynamic stall, a third color indicates the equipped aircraft is closer to aerodynamic stall, and a fourth color indicates a closest point to aerodynamic stall.

14. The method as claimed in Claim 13 further comprising a fifth color that indicates when the equipped aircraft is being flown in a best lift/drag condition.

15. The method as claimed in any of Claims 10-14, further comprising providing graduated auditory indications of direction of control needed, wherein the graduated auditory indications are a function of stall imminence, and wherein a volume of the auditory indications increases with an increase in angle of attack of the equipped aircraft.

16. The method as claimed in any of Claims 10-14, wherein the second graphic is more opaque than the first graphic, and the third graphic is more opaque than the second graphic.

17. An aircraft avionic system for use in an equipped aircraft, said system comprising: a controller and a display, said controller providing output data to said display, said output data producing visual images on said display;

an angle of attack data source providing current angle of attack data for the equipped aircraft;

said controller responsive to said angle of attack data in order to provide said output data to drive said display to depict a direction of control needed to preclude a stall, wherein said display of direction of control is graduated based on a current level of stall imminence, wherein said stall imminence is a function of the angle of attack of the equipped aircraft, and wherein the controller is configured to compare the received angle of attack data to a plurality of thresholds; wherein said controller is configured to select a normal flight condition if the angle of attack is below a first threshold, wherein a direction of control needed graphic displayed in an attitude display in the equipped aircraft is transparent;

wherein said controller is configured to select an "approaching aerodynamic stall" condition and graphically indicate a corresponding direction of control needed in a first graphic displayed in the attitude display when the angle of attack is above the first threshold but below a second threshold;

wherein said controller is configured to select a "closer to aerodynamic stall" condition, and graphically indicate a corresponding direction of control needed in a second graphic displayed in the attitude display, when the angle of attack is above the first and second thresholds, but below a third threshold; and

wherein said controller is configured to select a "closest to aerodynamic stall" condition, and graphically indicate a corresponding direction of control needed in a third graphic displayed in the attitude display when the angle of attack is above the first, second, and third thresholds.