Patent Publication Number: US-11644340-B2

Title: Automated avionics systems and methods for determining a modified path of descent of an aircraft

Description:
BACKGROUND 
     Automated avionics systems replace mechanical and electro-mechanical instrument gauges and controls historically used in aircraft with one or more electronic displays for displaying primary flight information such as attitude, altitude, heading, vertical speed, and so forth, to the pilot, and/or receiving command inputs from the pilot for controlling aircraft systems. Automated avionics systems may include one or more primary flight displays (PFD) and one or more multifunction displays (MFD). Further, automated avionics systems may provide one or more controllers, such as one or more avionics control and display units (CDU), which may provide a user interface (e.g., a touch interface) to allow the aircraft&#39;s flight crew (e.g., a pilot and/or a co-pilot) to control the operation of the aircraft via the PFD and/or the MFD and to view navigation information related to the route the aircraft is traversing. Integrated avionics systems also allow the flight crew to manually control operation of the aircraft&#39;s systems via the PFD, the MFD, or other controls. 
    
    
     
       DRAWINGS 
       The Detailed Description is described with reference to the accompanying figures. The use of the same reference numbers in different instances in the description and the figures may indicate similar or identical items. 
         FIG.  1    is a block diagram illustrating an automated avionics system for an aircraft in accordance with embodiments of the present disclosure. 
         FIG.  2    is an illustration depicting a representative example instrument panel of an aircraft including an automated avionics system configured in accordance with various implementations of the present disclosure. 
         FIG.  3    is a schematic view illustrating an exemplary system for determining a modified path of descent for an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  4    is a schematic view illustrating another exemplary system for determining a modified path of descent for an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  5    is a schematic view illustrating another exemplary system for determining a modified path of descent for an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  6    is a schematic view illustrating another exemplary system for determining a modified path of descent for an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  7    is a schematic view illustrating another exemplary system for determining a modified path of descent for an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  8    is a schematic view illustrating another exemplary system for determining a modified path of descent for an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  9    is a schematic view illustrating another exemplary system for determining a modified path of descent for an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  10    is a schematic view illustrating another exemplary system for determining a modified path of descent for an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  11    is a schematic view illustrating another exemplary system for determining a modified path of descent for an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  12 A  is a screenshot illustrating a display for displaying on graphical interface of an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  12 B  is another screenshot illustrating a display for displaying on graphical interface of an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  13    is another screenshot illustrating another display for displaying on a graphical interface of an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  14 A  is another screenshot illustrating another display for displaying on a graphical interface of an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  14 B  is a screenshot illustrating another display for displaying on a graphical interface of an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  15    is a screenshot illustrating another display for displaying on a graphical interface of an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  16    is a screenshot illustrating another display for displaying on a graphical interface of an automated avionics system, such as the automated avionics system illustrated in  FIG.  1   , in accordance with embodiments of the present disclosure. 
         FIG.  17 A  is a flow diagram illustrating an example process for determining a modified path of descent for an aircraft in accordance with an example implementation of the present disclosure. 
         FIG.  17 B  is a flow diagram illustrating an example process for determining a modified path of descent for an aircraft in accordance with an example implementation of the present disclosure. 
         FIG.  17 C  is a flow diagram illustrating an example process for determining a modified path of descent for an aircraft in accordance with an example implementation of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     An automated avionics system can include electronic devices, such as integrated avionics systems, which are utilized by one or more aircraft operators (e.g., a pilot and/or a co-pilot) to navigate an aircraft. Integrated avionics systems may employ primary flight display(s) (PFDs) and multifunction display(s) (MFDs) to furnish primary flight control, navigational, and other information to the flight crew of the aircraft. Additionally, the integrated avionics systems may also employ an avionics control and display unit (CDU) and/or other control devices that are configured to provide control functionality to the PFDs and/or the MFDs. 
     While automated avionics systems may provide the functionality flight crew and/or autopilot navigation of the aircraft (e.g., according to a predefined flight plan), these systems lack the ability to account for deviations from the flight plan without substantial pilot intervention. Under certain circumstances, it may be desirable to initiate descent of the aircraft prior to or after a predetermined top of descent point (TOD) associated with the flight plan, requiring a deviation from the original descent trajectory. For example, the pilot may receive authorization to initiate descent of the aircraft prior to reaching the TOD. In other circumstances, the pilot may reach or pass the TOD without receiving authorization to initiate descent. Under such circumstances, it may be desirable to initiate descent of the aircraft at a desired geographic location and/or altitude other than the TOD, while maintaining and/or accounting for aspects of the flight plan. For example, altering the TOD may necessitate accounting for one or more constraints (e.g., altitude constraints) associated with the flight plan, connecting with the original descent trajectory at a specified altitude constraint, and/or descending at an operator-selected rate of speed. There is a recognized need to provide functionality for determining a descent trajectory based on a revised TOD and accounting for one or more of these variables. 
     Accordingly, automated avionics systems and methods for determining a modified path of descent for an aircraft are described. In an embodiment, an automated avionics system includes a display device for providing a graphical interface for displaying flight-related information to a pilot, and an interface device disposed on the display device for receiving information from the pilot and allowing the pilot to interact with the graphical interface. The system further includes a memory operable to store a database related to a flight plan, the database including information related to the flight plan such as a position of descent for the aircraft, altitude constraint(s), and a path of descent including a vertical trajectory between the first position of descent and a downstream altitude point. The system further includes a processor communicatively coupled with the interface device and operatively coupled with the display device and the memory. The processor is operable to receive, from the interface device, an indication to initiate descent of the aircraft associated with a position of the aircraft, receive information related to the flight plan from the database, and perform modification(s) to the path of descent. Performing the modification(s) to the path of descent includes determining, based on a comparison of the first position of descent and the position of the aircraft, a deviation between the position of descent and the position of the aircraft, and based on the determination of a deviation from the position of descent, calculating a second position of descent based on the position of the aircraft. The processor is further operable to calculate a second path of descent based on the second position of descent and the downstream altitude point, the second path of descent including a vertical trajectory between the second position of descent and the downstream altitude point, the second path of descent complying with the altitude constraint(s) of the flight plan. In some embodiments, calculating the second path of descent includes determining, by whether the second path of descent complies with the altitude constraint(s); and when the second path of descent violates one or more of the altitude constraints, recalculating the second path of descent so that the vertical trajectory between the second position of descent and the downstream altitude point complies with the violated altitude constraints. The processor may be further operable to cause the display device to display the second path of descent to the pilot and/or send an indication to the pilot to cause the aircraft to initiate the second path of descent. The processor can be further operable to actuate the engine(s) and/or control column(s) of the aircraft to initiate descent. 
     Example Embodiments 
       FIGS.  1  and  2    illustrate an example embodiment of an automated avionics system (e.g., integrated avionics system  102 ) within an aircraft  100 . The integrated avionics system  102  generally includes an interface having a graphical interface  104 , a processor  150 , a memory  152 , a communications interface  154 . 
     The processor  150  provides functionality to the graphical interface  104 . For example, the processor  150  can be operably and/or communicatively coupled with the graphical interface  104 . The processor  150  can control the components and functions of the system  102  described herein using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or a combination thereof. The terms “controller,” “functionality,” “service,” and “logic” as used herein generally represent software, firmware, hardware, or a combination of software, firmware, or hardware in conjunction with controlling the system  102 . In the case of a software implementation, the module, functionality, or logic represents program code that performs specified tasks when executed on a processor (e.g., central processing unit (CPU) or CPUs). The program code can be stored in one or more computer-readable memory devices (e.g., internal memory and/or one or more tangible media), and so on. The structures, functions, approaches, and techniques described herein can be implemented on a variety of commercial computing platforms having a variety of processors. 
     The processor  150  provides processing functionality for the system  102  and can include any number of processors, micro-controllers, or other processing systems, and resident or external memory for storing data and other information accessed or generated by the system  102 . The processor  150  can execute one or more software programs that implement techniques described herein. The processor  150  is not limited by the materials from which it is formed or the processing mechanisms employed therein and, as such, can be implemented via semiconductor(s) and/or transistors (e.g., using electronic integrated circuit (IC) components), and so forth. 
     The system  102  includes a display device  112  and an interface device  114  that allows a pilot to provide input. In some embodiments, the interface device  114  is a touch screen interface, such as an electronic visual display that incorporates a touch panel overlying an electronic display to detect the presence and/or location of a touch within the display area of the screen. In these embodiments, the pilot can provide input using an instrument such as a finger, a stylus, and so forth. In some embodiments, the interface device  114  allows the pilot to provide to provide non-touch input via one or more keyboards, cursors, buttons, knobs, dials, control columns, and so forth. 
     The display device  112  can include an LCD (Liquid Crystal Diode) display, a TFT (Thin Film Transistor) LCD display, an LEP (Light Emitting Polymer) or PLED (Polymer Light Emitting Diode) display, and so forth, configured to display text and/or graphical information such as graphical interface  104  on a display screen. The display device  112  can be backlit via a backlight such that it can be viewed in the dark or other low-light environments. In some embodiments, the display device  112  can be disposed on an instrument panel of the aircraft, a pedestal area of the aircraft, an outboard area of the aircraft, and so forth. In embodiments, the integrated avionics system  102  can include one or more display devices  112  providing differing functionality including, but not limited to: PFD(s), MFD(s), head up display(s) (HUDs), secondary display unit(s) (SDUs) and so forth. In some embodiments, the system  102  includes multiple display devices  112  and corresponding graphical interfaces  104 . The display device(s)  112  may furnish a general-purpose pilot interface to control the aircraft&#39;s avionics. For example, the display devices  112  allow the pilots to control various systems of the aircraft such as the aircraft&#39;s autopilot system, navigation systems, communication systems, engines, and so on, via the avionics data bus. In implementations, the avionics data bus may include a high-speed data bus (HSDB), such as data bus complying with ARINC 429 data bus standard promulgated by the Airlines Electronic Engineering Committee (AEEC), a MIL-STD-1553 compliant data bus, and so forth. 
     The interface device  114  can be coordinated with the display device  112  for entry of data and commands. In embodiments including a touch interface device, the operator may use his or her fingers to manipulate images on the display device  112 . The interface device  114  can be disposed on the display device  112 , external to the display device  112 , or a combination thereof. In some embodiments, the display device  112  is operable by a combination of direct touch received at the display device  112  and input received external to the display device  112 . 
     In embodiments including a touch interface device, the interface device  114  includes a touch surface  116 . For example, the touch surface  116  can be a resistive touch screen, a surface acoustic wave touch screen, a capacitive touch screen, an infrared touch screen, optical imaging touch screens, dispersive signal touch screens, acoustic pulse recognition touch screens, combinations thereof, and the like. Capacitive touch screens can include surface capacitance touch screens, projected capacitance touch screens, mutual capacitance touch screens, and self-capacitance touch screens. In implementations, the touch surface  116  is configured with hardware to generate a signal to send to a processor and/or driver upon detection of touch information (e.g., a touch input). As indicated herein, touch inputs include inputs, gestures, and movements where the input contacts the touch surface  116 . In embodiments, the interface device  114  can receive touch information from an operator (e.g., user such as a pilot and/or a co-pilot) to interact with the graphical interface  104  displayed on the display screen. In some embodiments, the graphical interface  104  may include both active portions (e.g., areas that are responsive to operator touch information) and non-active portions (e.g., areas that are not responsive to operator touch information). In implementations, keyboards, cursors, buttons, softkeys, keypads, knobs and so forth, may be used for entry of data and commands instead of or in addition to the touch surfaces  116 . 
     In embodiments, the graphical interface  104  is configured for displaying flight information (e.g., interactive flight-related information  106 ). In some embodiments, the flight information includes information related to the flight plan of an aircraft (e.g., a vertical trajectory, constraints, etc.) as described below. In some embodiments, the interactive flight-related information  106  is displayed in one or more primary flight windows (PFWs), one or more multifunction windows (MFWs), or a combination thereof. The PFWs may be configured to display primary flight information, such as aircraft attitude, altitude, heading, vertical speed, and so forth. In embodiments, the PFWs may display primary flight information via a graphical representation of basic flight instruments such as an attitude indicator, an airspeed indicator, an altimeter, a heading indicator, a course deviation indicator, and so forth. The PFWs may also display other flight-related information providing situational awareness to the pilot such as terrain information, ground proximity warning information, weather information, and so forth. 
     In embodiments, The MFWs display interactive flight-related information  106  describing operation of the aircraft such as navigation routes, moving maps, engine gauges, weather radar, terrain alerting and warning system (TAWS) displays, ground proximity warning system (GPWS) displays, traffic collision avoidance system (TCAS) displays, airport information, and so forth, that are received from a variety of aircraft systems via the avionics data bus and/or are self-contained within the display device  112 . In some embodiments, the PFW may provide the functionality of an MFW. Where the system  102  includes multiple MFWs, MFWs that control a common systemwide value/state can be cross-filled when multiple instances viewing this value are active substantially simultaneously. Further, the display device  112  may be capable of displaying multiple instances of the same application in multiple MFWs, for example, with no restrictions on the number of the same application that could be displayed substantially simultaneously. In some embodiments, MFWs and/or PFWs shall support display and/or control of third-party applications (e.g., video, hosted applications, ARINC 661, etc.). 
     The system  102  further includes a communications interface  154 . The communications interface  154  is operatively configured to communicate with components of the system  102 . For example, the communications interface  154  can be configured to transmit data for storage in the system  102 , retrieve data from storage in the system  102 , and so forth. The communications interface  154  is also communicatively coupled with the processor  150  to facilitate data transfer between components of the system  102  and the processor  150  (e.g., for communicating inputs to the processor  150  received from a device communicatively coupled with the system  102 ). It should be noted that while the communications interface  154  is described as a component of a system  102 , one or more components of the communications interface  154  can be implemented as external components communicatively coupled to the system  102  via a wired and/or wireless connection. The system  102  can also include and/or connect to one or more input/output (I/O) devices (e.g., via the communications interface  154 ), including, but not necessarily limited to: a display, a mouse, a touchpad, a keyboard, and so on. 
     The communications interface  154  and/or the processor  150  can be configured to communicate with a variety of different networks, including, but not necessarily limited to: ARINC 429; RS-232; RS-422; CAN Bus; ARINC 661; a wide-area cellular telephone network, such as a 3G cellular network, a 4G cellular network, or a global system for mobile communications (GSM) network; a wireless computer communications network, such as a WiFi network (e.g., a wireless local area network (WLAN) operated using IEEE 802.11 network standards); an internet; the Internet; a wide area network (WAN); a local area network (LAN); a personal area network (PAN) (e.g., a wireless personal area network (WPAN) operated using IEEE 802.15 network standards); a public telephone network; an extranet; an intranet; and so on. However, this list is provided by way of example only and is not meant to limit the present disclosure. Further, the communications interface  154  can be configured to communicate with a single network or multiple networks across different access points. 
     The memory  152  is an example of tangible, computer-readable storage medium that provides storage functionality to store various data associated with operation of the system  102 , such as software programs and/or code segments, or other data to instruct the processor  150 , and possibly other components of the system  102 , to perform the functionality described herein. Thus, the memory  152  can store data, such as a program of instructions for operating the system  102  (including its components), and so forth. It should be noted that while a single memory  152  is described, a wide variety of types and combinations of memory (e.g., tangible, non-transitory memory) can be employed. The memory  152  can be integral with the processor  150 , can include stand-alone memory, or can be a combination of both. 
     The memory  152  can include, but is not necessarily limited to: removable and non-removable memory components, such as random-access memory (RAM), read-only memory (ROM), flash memory (e.g., a secure digital (SD) memory card, a mini-SD memory card, and/or a micro-SD memory card), magnetic memory, optical memory, universal serial bus (USB) memory devices, hard disk memory, external memory, and so forth. In implementations, the system  102  and/or the memory  152  can include removable integrated circuit card (ICC) memory, such as memory provided by a subscriber identity module (SIM) card, a universal subscriber identity module (USIM) card, a universal integrated circuit card (UICC), and so on. In embodiments, the memory  152  includes one or more software modules capable of being executed by the processor  150 , and one or more data sets and/or databases. 
     In embodiments, the memory  152  is operable to store a database of flight-related information associated with a flight plan of the aircraft. Flight-related information associated with the flight plan can include: a position of descent for the aircraft (also noted as top of descent or TOD), geographical constraints, and a path of descent including a vertical trajectory between the first position of descent and a downstream geographical point (e.g. a downstream altitude point). The geographical constraints include passage points for the aircraft in a horizontal plane, with which are associated possible constraints (e.g., altitude constraints, speed constraints, time constraints, etc.). In a specific embodiment, the altitude constraints each define an altitude above, below, or at which the aircraft has to fly at a given point. Each altitude constraint is thus associated with a constrain point above (“ABOVE constraint”), below (“BELOW constraint”), between (“BETWEEN constraint”), or through (“AT constraint”) which the aircraft  100  must pass. In specific embodiments, the downstream altitude point is an AT constraint, a Final Approach Fix (“FAF”), or a waypoint. 
     It is to be understood that flight-related information associated with the flight plan can be obtained from a variety of sources including, but not limited to: pilot input, data received from other aircraft systems, data received from aircraft instrumentation, and so forth. In specific embodiments, one or more types of flight-related information are calculated by the system  102  and storable in memory  152 . For example, the processor  150  is operable to determine the TOD and/or path of descent based on other flight-related information (e.g., altitude constraints, waypoints, path types, latitude/longitude positions, etc.). 
     In embodiments, the processor  150  is operable to interface with the memory  152  to determine a modified (e.g., new or revised) path of descent for the aircraft  100 . In embodiments, the processor  150  is operable to determine a new path of descent for the aircraft  100  based on a modified TOD. For example, the processor  150  can initiate descent of the aircraft  100  upstream or downstream of the original TOD of the flight plan based on an indication received from the interface device  114 . In some embodiments, the processor  150  receives from the interface device  114 , an indication to initiate descent of the aircraft  100  (“descent indication”) at a real-time geographical position associated with the aircraft  100 , for example, at a current position or a downstream position of the aircraft  100 . It is to be understood that while modifying the path of descent by determining a new path of descent is described herein, modifying the path of descent can also include revising the original path of descent, for example by modifying one or more portions of the original path of descent while retaining other portions. 
     Referring now to  FIGS.  3  through  11   , example paths of descent  160  and modified paths of descent  162  for an aircraft  100  are shown. In  FIGS.  3  through  11   , the vertical axis indicates the altitude of the aircraft  100  relative to a reference altitude, and the horizontal axis designates a curvilinear abscissa of the aircraft  100  in a horizontal plane. The illustrated trajectories therefore represent the successive altitudes of the aircraft  100  during a movement of the aircraft  100 . 
     Referring now to  FIG.  3   , the processor  150  is operable to interface with the memory  152  to determine a modified path of descent  162  for the aircraft  100  that complies with one or more constraints of the flight plan. In some embodiments, the processor  150  is operable to determine a modified path of descent for the constraints corresponding to altitude constraints of the flight plan, which must be observed by the aircraft  100  during its descent, as illustrated in  FIG.  3   . Example constraints include one or more BETWEEN constraint  164 A defining a maximum altitude and a minimum altitude that the aircraft  100  must pass between in a given passage point in the horizontal plane, one or more BELOW constraint  164 B defining a maximum altitude in another passage point in the horizontal plane, and one or more AT constraint  164 C defining an imposed altitude of the aircraft  100  in a passage point in the horizontal plane. In some implementations, the flight plan further includes one or more ABOVE constraint  164 D defining a minimum altitude of the aircraft  100  in a passage point in the horizontal plan (e.g., as described with reference to  FIG.  4   ) 
     In some implementations, the processor  150  is operable to interface with the memory  152  to determine whether a deviation is present between the original TOD  166  and the position of the aircraft associated with the descent indication. For example, the processor  150  can detect a deviation, greater than a predetermined deviation threshold, between the altitude of the aircraft in the indicated point in the horizontal plane and the altitude in this given point as provided by the original descent trajectory. This deviation threshold corresponds to a tolerance margin between the altitude of the aircraft at the indicated point and the altitude provided by the original descent trajectory. 
     In some implementations, the processor  150  is operable to interface with the memory  152  to determine a modified path of descent  162  for the aircraft  100  based on a descent indication including a position of the aircraft  100  that is upstream from the original TOD  166  of the flight plan (e.g., as described with reference to  FIGS.  3  through  6   ). In such implementations, the processor  150  determines a modified position of descent (e.g., modified TOD  168 ) based on the real-time position of the aircraft  100  and/or a downstream altitude position of the aircraft  100 , the modified TOD  168  being upstream from the original TOD  166 . In some embodiments, the modified TOD  168  corresponds directly to the indicated position of descent. In other embodiments, the TOD  168  may include a position downstream from the indicated position of descent or the real-time position of the aircraft to provide an adequate transition between the level flight phase and the descent phase. The processor  150  then calculates a modified path of descent  162  including a vertical trajectory between the modified position of descent  168  and next downstream AT constraint  164 C in the horizontal plane. 
     Referring now to  FIG.  4   , the modified path of descent  162  may violate one or more constraints of the flight plan. In such implementations, the processor  150  is operable to recalculate the modified path of descent  162  so that the vertical trajectory complies with all downstream constraints. The processor  150  determines a recalculated path of descent  162 A by determining a vertical trajectory between the modified TOD  168  and the furthest reachable constraint that matches the constraint crossing type of the first constraint violated by the modified path of descent without violating any intermediate constraints. For example, the processor  150  can calculate a vertical trajectory between the modified TOD  168  and the BETWEEN constraint  164 A without violating the intermediate ABOVE constraint  164 D. In such embodiments, the original descent path  160  is joined beyond the furthest reachable constraint. For example, the processor  150  can calculate a vertical trajectory between the furthest reachable constraint (e.g., BETWEEN constraint  164 A) and the AT constraint  164 C without violating the intermediate BELOW constraint  164 B. In some implementations, the processor  150  treats the furthest reachable constraint as an AT constraint to optimize the recalculated path of descent  162 A. For example, the processor  150  can calculate a vertical trajectory between the modified TOD  168  and the maximum altitude associated with the BETWEEN constraint  164 A. By determining the recalculated path of descent  162 A based on the furthest reachable constraint, the processor  150  provides a recalculated path of descent  162 A that rejoins the original descent path  160  while minimizing fluctuations in flight path angle. Treating the furthest reachable constraint as an AT constraint further reduces fluctuations in the flight path angle and/or slope of descent path. 
     Referring now to  FIGS.  5  and  6   , the processor  150  can determine a recalculated path of descent  162 A that rejoins the original descent path  160  beyond the furthest reachable constraint without violating further downstream constraints. In some implementations, the processor  150  can calculate a vertical trajectory directly between the furthest reachable constraint (e.g., ABOVE constraint  164 D) and the AT constraint  164 C that does not violate any intermediate constraints (e.g., BETWEEN constraint  164 A; as described with reference to  FIG.  5   ). In other implementations, the processor  150  cannot calculate a vertical trajectory directly between the furthest reachable constraint (e.g., ABOVE constraint  164 D) and the AT constraint  164 C without violating an intermediate constraint (e.g., ABOVE constraint  164 E). In these implementations, the processor  150  will calculate a vertical trajectory between the furthest reachable constraint (e.g., ABOVE constraint  164 D) and the AT constraint  164 C that complies with the intermediate constraint (e.g., ABOVE constraint  164 E). In some implementations, the processor  150  treats the intermediate constraint as an AT constraint to optimize the recalculated path of descent  162 B. For example, the processor  150  can calculate a vertical trajectory between the furthest reachable constraint (e.g., ABOVE constraint  164 D) and the AT constraint  164 C that passes the intermediate ABOVE constraint  164 E at the maximum altitude associated with the intermediate ABOVE constraint  164 E. Treating the intermediate constraint as an AT constraint reduces fluctuations in the flight path angle and/or slope of descent path. 
     Referring now to  FIGS.  7  and  8   , the processor  150  is operable to interface with the memory  152  to determine a modified path of descent  162  for the aircraft  100  based on a descent indication including a position of the aircraft  100  that is downstream from the original TOD  166  of the flight plan. In such implementations, the processor  150  determines a modified position of descent (e.g., modified TOD  168 ) based on the real-time position of the aircraft  100  and/or a downstream altitude position of the aircraft  100 , the modified TOD  168  being downstream from the original TOD  166 . The processor  150  then calculates a modified path of descent  162  including a vertical trajectory between the modified position of descent  168  and next downstream AT constraint  164 C in the horizontal plane. 
     Utilizing techniques described above, the processor  150  is operable to recalculate the modified path of descent  162  so that the vertical trajectory based on the downstream modified TOD  168  complies with all downstream constraints. For example, the processor  150  determines a recalculated path of descent  162 A by calculating a vertical trajectory between the modified TOD  168  and the BETWEEN constraint  164 A. In such embodiments, the original descent path  160  is joined beyond the furthest reachable constraint. For example, the processor  150  can calculate a vertical trajectory between the furthest reachable constraint (e.g., BETWEEN constraint  164 A) and the AT constraint  164 C without violating the intermediate BELOW constraint  164 B. In some implementations, the processor  150  treats the furthest reachable constraint as an AT constraint to optimize the recalculated path of descent  162 A. For example, the processor  150  can calculate a vertical trajectory between the modified TOD  168  and the maximum altitude associated with the BETWEEN constraint  164 A. By determining the recalculated path of descent  162 A based on the furthest reachable constraint, the processor  150  provides a recalculated path of descent  162  that rejoins the original descent path  160  while minimizing fluctuations in flight path angle. Treating the furthest reachable constraint as an AT constraint further reduces fluctuations in the flight path angle and/or slope of descent path. 
     Referring now to  FIGS.  9  through  11   , the processor  150  is operable to interface with the memory  152  to determine a modified path of descent  162  for the aircraft  100  by executing a flight path algorithm based on one or more operator-selected or predefined characteristics (e.g., descent rate, flight path angle limit). In such implementations, the processor  150  determines a modified position of descent (e.g., modified TOD  168 ) based on the real-time position of the aircraft  100  and/or a downstream altitude position of the aircraft  100 . The processor  150  then calculates a modified path of descent  162  including a vertical trajectory between the modified position of descent  168  and the original path of descent  160  based on the selected descent rate. For example, the processor  150  determines a flight path angle (“FPA”)  170  for intercepting the original path of descent  160  using the following flight path algorithm: 
     
       
         
           
             
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               P 
               ⁢ 
               A 
             
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               - 
               
                 
                   tan 
                   
                     - 
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                 ⁡ 
                 
                   ( 
                   
                     
                       desired_fpm 
                       ⁢ 
                       _dscnt 
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                       _rate 
                     
                     ground_speed 
                   
                   ) 
                 
               
             
           
         
       
     
     The processor  150  then determines if the modified path of descent  162  violates any constraints (e.g., BETWEEN constraint  164 A, BELOW constraint  164 B) of the flight plan. Where no constraints are violated, the calculated flight path angle  170  required for the selected descent rate is maintained until the modified path of descent  162  intercepts the original path of descent  160  (e.g., as described with reference to  FIG.  9   ). 
     In some implementations, the modified path of descent  162  based on the calculated flight path angle  170  and the selected descent rate may violate one or more constraints of the flight plan (e.g., as described with reference to  FIG.  10   ). In such implementations, the processor  150  is operable to recalculate the modified path of descent  162  so that the vertical trajectory complies with all downstream constraints. In some implementations, the processor  150  determines a recalculated path of descent  162 A by determining a vertical trajectory between the modified TOD  168  and the furthest limiting ABOVE constraint before the original path of descent  160  is intercepted (e.g., as described with reference to  FIG.  10   ). For example, the processor  150  can calculate a vertical trajectory between the modified TOD  168  and the ABOVE constraint  164 D without violating the intermediate ABOVE constraint  164 F. In such embodiments, the processor  150  can determine a descent rate that differs from the selected descent rate, for example to avoid level-off at the ABOVE constraint  164 D. For example, the actual descent rate may be slower or faster than the selected descent. In some embodiments, the processor  150  determines the steepest descent rate and corresponding FPA  170 A that complies with the constraints of the flight plan. 
     For example, the processor  150  can calculate a vertical trajectory between the furthest reachable constraint (e.g., BETWEEN constraint  164 A) and the AT constraint  164 C without violating the intermediate BELOW constraint  164 B. In some implementations, the processor  150  treats the furthest reachable constraint as an AT constraint to optimize the recalculated path of descent  162 A. For example, the processor  150  can calculate a vertical trajectory between the modified TOD  168  and the maximum altitude associated with the BETWEEN constraint  164 A. By determining the recalculated path of descent  162 A based on the furthest reachable constraint, the processor  150  provides a recalculated path of descent  162 A that rejoins the original descent path  160  while minimizing fluctuations in flight path angle. Treating the furthest reachable constraint as an AT constraint further reduces fluctuations in the flight path angle and/or slope of descent path. 
     In some embodiments, the processor  150  is operable to interface with the memory  152  to provide an indication to the pilot to cause the aircraft to initiate the modified path of descent  162  (or the recalculated path of descent  162 A). For example, the processor  150  may display, via the display device  112 , a prompt requiring the pilot to accept or decline initiation of the modified path of descent  162 . The pilot can then engage one or more components and/or systems of the aircraft that are internal and/or external to the system  102  for initiating or traversing the modified path of descent  162 , as described below. In some embodiments, the processor  150  is operable to interface with the memory  152  to elicit operator confirmation of a modified path of descent  162  for the aircraft  100  that violates an operator-selected and/or predefined characteristic, as described below. If the operator terminates the modified path of descent  162 , the processor  150  may be operable to adjust the modified path of descent  162  to comply with the operator-selected and/or predefined characteristics. 
     In one or more embodiments, the processor  150  is operable to engage one or more control systems of the aircraft  100  to initiate the modified path of descent  162  (or recalculated path of descent  162 A). In some implementations, the processor  150  can cause the flight director, autopilot system, and/or navigation system to actuate one or more modes of operation. For example, the processor  150  can cause the autopilot system to actuate the vertical navigation mode (VNAV) to traverse the vertical trajectory. The processor  150  can also cause the autopilot system to actuate a flight level change (FLC) mode and/or an altitude hold mode (ALT) to achieve and/or maintain desired airspeed and/or altitude while traversing the vertical trajectory. 
     The processor  150  is further operable to engage one or more components and/or systems of the aircraft that are internal and/or external to the system  102  for initiating or traversing the modified path of descent  162  (or recalculated path of descent  162 A). In some embodiments, the processor  150  can actuate one or more systems and/or modes of operation of an aircraft engine. For example, the processor  150  can actuate the autothrottle system to control power of the engine. The autothrottle system can maintain predetermined speed and/or thrust during different phases of flight (e.g., cruise, descent, hold, near destination, approach, landing flare, inside the approach fix, etc.). For example, the autothrottle system can control the power of the engine to maintain the operator-selected descent rate. 
       FIGS.  12 A through  16    illustrate example displays  200  furnishing flight information to the pilot and configured to receive input from the pilot and provide functionality for the pilot to engage with the graphic interface  104 . For example, the display  200  can include information related to the flight plan including, but not limited to: a moving map, flight path angle, descent rate, navigation information, and so forth. In some embodiments, the processor  150  may cause the modified path of descent  162  and/or the recalculated path of descent  162 A to be displayed to the pilot via one or the more display devices  112  and graphical interface  104  of the aircraft  100 . For example, one or more of the moving maps, virtual situation displays, and/or synthetic vision technology displays of the graphical interface  104  may be updated to include the modified path of descent  162  and/or recalculated path of descent  162 A. 
     In some embodiments, the display  200  can include one or more selectable items (buttons, selectable menus, etc.) for receiving input from the pilot. For example, the display  200  can include a selectable button  202  for initiating descent of the aircraft  100  (e.g., as described with reference to  FIG.  12 A ). The pilot can select the button by touch input (e.g., via touch surface  116 ) to cause the processor  150  to engage the descent functionality described above (e.g., as described above with reference to  FIGS.  3  through  11   ). In some embodiments, the processor  150  may populate the graphical interface  104  with additional selectable descent option(s) (e.g., selectable option button  212 ) based upon receiving a selection of selectable button  202  (e.g., as described with reference to  FIG.  12 B ). In some embodiments, the display  200  can include a selectable menu  204  having a selectable menu option  206  (e.g., as described with reference to  FIG.  13   ). The pilot can select the selectable menu option  206  (e.g., via touch surface  116 ) to cause the processor  150  to engage descent functionality described above. It is to be understood that the use of touch inputs (buttons, selectable menus, etc.) received via a touch surface is provided by way of example only. In other embodiments, pilot input can be received from other input devices (buttons, cursors, bezels, wheels, etc.) of the integrated avionics system  102 . 
     In some embodiments, the display  200  is configured for receiving operator-selected characteristics related to the modified path of descent  162  (e.g., descent rate, flight path angle limit, etc.). For example, the display  200  can include a selectable button  210  for inputting a desired descent rate, minimum descent rate, or maximum descent rate (e.g., as described with reference to  FIG.  15   ). In some embodiments, the display  200  is configured for receiving input from the operator to confirm or terminate the modified path of descent  162  based on operator-selected and/or predefined characteristics (e.g., descent rate, flight path angle limit, etc.). For example, when the modified path of descent  162  violates an operator-selected or predefined characteristic, a modal popup  208  can be displayed requiring the operator to approve or cancel initiation of the modified path of descent (e.g., as described with reference to  FIGS.  14 A,  14 B,  16   ). 
     Example Processes 
       FIGS.  17 A- 17 C  depicts an example process  250  for initiating descent of an aircraft utilizing an automated avionics system, such the integrated avionics system  102  described above. As shown in  FIG.  17 A , an indication to initiate descent of the aircraft (“descent indication”) is received, the descent indication being associated with a position of the aircraft (Block  252 ). In embodiments, the descent indication may include a real-time geographical and altitude position associated with the aircraft, for example, at a current position or a downstream position of the aircraft (“indicated position of descent”). 
     Information associated with a flight plan for the aircraft is received, the information including a first position of descent for the aircraft (e.g., original TOD  166 ), one or more altitude constraints, and a first path of descent (“original path of descent”) including a vertical trajectory between the first position of descent and a downstream altitude point (Block  254 ). As described above, the processor  150  is operable to receive flight plan information from a database of flight-related information associated with the flight plan stored in memory  152 . In specific embodiments, the downstream altitude point is an AT constraint and/or a Final Approach Fix (“FAF”). 
     At least one modification of the first path of descent is performed (Block  256 ). In embodiments, performing a modification of the first path of descent can include determining a new path of descent based on a modified TOD and/or performing one or more revisions of the first path of descent. 
     The original position of descent is compared to the position of the aircraft included in the descent indication (Block  258 ). A determination is made of whether there is a deviation between the original position of descent and the indicated position of descent (Decision Block  260 ). In some embodiments, the processor  150  can detect a deviation, greater than a predetermined deviation threshold, between the altitude of the aircraft in the indicated point in the horizontal plane and the altitude in this given point as provided by the original descent trajectory, as described above. 
     Where no deviation is detected between the original position of descent and the indicated position of descent, the original path of descent is maintained (Block  262 ). When a deviation is detected between the original position of descent and the indicated position of descent, a second position of descent (e.g., modified TOD  168 ) is determined based on the indicated position (Block  264 ). As described above, the modified TOD  168  may correspond directly to the indicated position, or may be downstream of the indicated position to provide an adequate transition between the level flight and descent phases. 
     A second path of descent (“modified path of descent”) is calculated based on the second position of descent and the downstream altitude point (Block  266 ). The modified path of descent includes a vertical trajectory between the second position of descent and the downstream altitude point, and complies with the downstream altitude constraint(s) of the flight plan. As described above, the processor  150  then calculates a modified path of descent  162  including a vertical trajectory between the modified position of descent  168  and next downstream AT constraint  164 C in the horizontal plane. In some implementations, calculating a second path of descent includes comparing the second path of descent with the altitude constraints of the flight plan (Block  268 ). A determination is made of whether any downstream altitude constraints of the flight plan are violated by the modified path of descent (Decision Block  270 ). Where no downstream altitude constraints are violated, the modified path of descent is initiated by actuating an engine, control column, or other control of the aircraft (Block  284 ). 
     Where one or more downstream altitude constraints are violated, the furthest reachable downstream violated altitude constraint is identified (Block  274 ). In some implementations, a first intermediate vertical trajectory is determined between the second position of descent and the furthest downstream violated altitude constraint (Block  276 ). In such implementations, a second intermediate vertical trajectory is determined between the furthest violated altitude constraint and the downstream altitude point (Block  278 ). As described above with reference to  FIG.  4   , the processor  150  can calculate a vertical trajectory between the modified TOD  168  and the BETWEEN constraint  164 A without violating the intermediate ABOVE constraint  164 D. In such embodiments, the original descent path  160  is joined beyond the furthest reachable constraint. For example, the processor  150  can calculate a vertical trajectory between the furthest reachable constraint (e.g., BETWEEN constraint  164 A) and the AT constraint  164 C without violating the intermediate BELOW constraint  164 B. In some implementations, the furthest reachable constraint is treated as an AT constraint to optimize the modified path of descent. As described above with reference to  FIG.  4   , the processor  150  can calculate a vertical trajectory between the modified TOD  168  and the maximum altitude associated with the BETWEEN constraint  164 A. By determining the recalculated path of descent  162 A based on the furthest reachable constraint, the processor  150  provides a recalculated path of descent  162 A that rejoins the original descent path  160  while minimizing fluctuations in flight path angle. Treating the furthest reachable constraint as an AT constraint further reduces fluctuations in the flight path angle and/or slope of descent path. 
     In some implementations, the modified path of descent is displayed to the pilot (Block  280 ). As described above, the processor  150  may cause the modified path of descent  162  (or recalculated path of descent  162 A) to be displayed to the pilot via one or the more display devices  112  of the aircraft  100 . For example, one or more of the moving maps of the graphical interface  104  may be updated to include the modified path of descent. 
     In some embodiments, an indication is sent to the pilot to cause the aircraft to initiate the modified path of descent  162  (or the recalculated path of descent  162 A) (Block  282 ). For example, the processor  150  may display, via the display device  112 , a prompt requiring the pilot to accept or decline initiation of the modified path of descent  162 . In the event that the pilot declines initiation of the modified path of descent  162 , the original path of descent is maintained. 
     The modified path of descent is initiated by actuating an engine, control column, or control system of the aircraft (Block  284 ). As described above, the processor  150  is operable to engage one or more control systems of the aircraft  100  to initiate the modified path of descent  162  (or recalculated path of descent  162 A). In some implementations, the processor  150  can cause the flight director, autopilot system, and/or navigation system to actuate one or more modes of operation. For example, the processor  150  can cause the autopilot system to actuate the VNAV to traverse the vertical trajectory. The processor  150  can also cause the autopilot system to actuate a FLC mode and/or an ALT mode to achieve and/or maintain desired airspeed and/or altitude while traversing the vertical trajectory. In some embodiments, the processor  150  can actuate one or more systems and/or modes of operation of the aircraft engine. For example, the processor  150  can actuate the autothrottle system to control power of the engine and maintain an operator-selected descent rate. 
     It is to be understood that the terms “operator” and “pilot” are used interchangeably herein to describe any pilot, co-pilot, crew member, or other person who operates or controls the aircraft. It is to be further understood that the terms “operator” and “pilot” are also used interchangeably herein to describe any autonomous or semi-autonomous system that operates or controls the aircraft. 
     Generally, any of the functions described herein can be implemented using hardware (e.g., fixed logic circuitry such as integrated circuits), software, firmware, manual processing, or a combination thereof. Thus, the blocks discussed in the above disclosure generally represent hardware (e.g., fixed logic circuitry such as integrated circuits), software, firmware, or a combination thereof. In the instance of a hardware configuration, the various blocks discussed in the above disclosure may be implemented as integrated circuits along with other functionality. Such integrated circuits may include all of the functions of a given block, system, or circuit, or a portion of the functions of the block, system, or circuit. Further, elements of the blocks, systems, or circuits may be implemented across multiple integrated circuits. Such integrated circuits may include various integrated circuits, including, but not necessarily limited to: a monolithic integrated circuit, a flip chip integrated circuit, a multichip module integrated circuit, and/or a mixed signal integrated circuit. In the instance of a software implementation, the various blocks discussed in the above disclosure represent executable instructions (e.g., program code) that perform specified tasks when executed on a processor. These executable instructions can be stored in one or more tangible computer readable media. In some such instances, the entire system, block, or circuit may be implemented using its software or firmware equivalent. In other instances, one part of a given system, block, or circuit may be implemented in software or firmware, while other parts are implemented in hardware. 
     Although the subject matter has been described in language specific to structural features and/or process operations, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.