A takeoff performance monitoring method and system based on dynamic safety margin calculation

Abstract

This application relates to a takeoff performance monitoring method and system based on dynamic safety margin calculation, including: a) real-time acquisition of relevant takeoff performance parameters; b) calculation of the current available runway distance, takeoff ground taxi distance, RTO distance, and safety margin coefficient based on the takeoff performance parameters; c) determining whether the takeoff performance verification passes based on the minimum safety margin coefficient which is greater than (current available runway distance >= (takeoff ground taxi distance + required RTO distance)); if not satisfied, triggering an alarm message; d) if satisfied, continuously verifying takeoff performance based on real-time takeoff performance parameters until the aircraft begins to perform takeoff maneuvers, and then executing the following steps: adopting different takeoff performance monitoring schemes according to different safety margins; if the optimal safety margin condition is met, then executing explicit latching; if the optimal safety margin condition is not met but the minimum safety margin condition is met, then executing explicit latching and continuously monitoring takeoff performance until the aircraft reaches V1 speed.

Description

Technical Field

[0001] This application belongs to the field of avionics systems, particularly avionics human-machine interfaces, and more specifically, relates to a takeoff performance monitoring method and system based on dynamic safety margin calculation. Background Technology

[0002] With EASA listing "aircraft performance data input" as a top-priority safety issue and promoting the installation of takeoff configuration warning and real-time performance monitoring systems, takeoff performance monitoring technology has moved from an optional auxiliary to a core element of mandatory compliance.

[0003] Among the current mainstream civilian aircraft models, some have already taken the lead in responding to EASA's initiative and providing takeoff performance monitoring functions.

[0004] The draft of Clause 704, which addresses takeoff performance monitoring, explicitly mentions the need for crews to monitor the validity and input of the VSPD (Vehicle Stability and Performance Detection Device). Based on the operational requirements of current mainstream aircraft models, before takeoff thrust or crew acceleration, the presence of the VSPD can be visually observed on the display, and simple verification can be performed when entering the VSPD on the FMS (Flight Management System) page (similar to monitoring takeoff speed values ​​on some aircraft models). However, at the actual initial takeoff position, errors in taxiway entry or excessive takeoff line displacement may occur, resulting in safety impacts on takeoff performance even though runway and VSPD information are entered correctly.

[0005] Furthermore, while the descriptions of existing aircraft models and publicly available technical solutions take into account whether the remaining runway distance can meet the takeoff requirements, they do not consider the dynamic changes in the runway length required for takeoff and the safety margin under different conditions (these conditions include the influence of internal aircraft system factors and external environmental factors).

[0006] Therefore, a method is needed to provide a comprehensive calculation of takeoff safety margins under different conditions based on factors affecting takeoff performance, such as the actual system status of the aircraft, the external environment during takeoff, and personal factors. This would allow for the adoption of different takeoff performance monitoring schemes based on the actual conditions of the required runway, and timely warnings when takeoff performance requirements are not met, in order to comply with the requirements of EASA Clause 704. Summary of the Invention

[0007] This application provides a takeoff performance monitoring method and system based on dynamic safety margin calculation. The scheme includes calculating corresponding safety margins based on influencing factors such as the aircraft's existing real-time system status monitoring, the external takeoff environment, and personal factors. These safety margins include at least an optimal safety margin and a minimum safety margin. The system can dynamically activate different takeoff performance monitoring mechanisms based on calculated safety margins using parameters such as takeoff runway information, taxiway information, and the aircraft's real-time position, ensuring that the remaining runway distance meets takeoff performance requirements.

[0008] According to a first aspect of this application, a takeoff performance monitoring method based on dynamic safety margin calculation is provided, comprising: a) Real-time acquisition of relevant takeoff performance parameters; b) Calculate the current runway available distance, takeoff ground taxiing distance, RTO distance, and the optimal and minimum safety margin coefficients for this takeoff based on the collected takeoff performance parameters. c) Determine whether the takeoff performance verification has passed based on the following conditions: The current available runway distance is greater than or equal to the larger of (takeoff ground distance and required RTO distance). Minimum safety margin factor? If the above conditions are not met, relevant alarm information will be triggered. If the above conditions are met, the takeoff performance verification will continue based on the real-time collected takeoff performance parameters until the aircraft begins to perform takeoff maneuvers, at which point the following steps will be executed: When an aircraft is taking off, if the condition is met that "current available runway distance >= (required takeoff distance, required RTO distance)", then the aircraft must meet the greater of these two conditions. If the condition of "optimal safety margin coefficient" is met, the currently displayed takeoff performance parameters will be displayed and latched, and the takeoff performance monitoring process will end. When an aircraft is taking off, if the condition is not met that "current available runway distance >= (required takeoff distance, required RTO distance)", then... The condition of "optimal safety margin coefficient" must be met, but the condition of "current available runway distance >= (takeoff ground taxi distance, required RTO distance)" must be satisfied. When the condition of "minimum safety margin coefficient" is met, the takeoff performance verification will continue while the display latch is being performed until the aircraft reaches V1 speed.

[0009] According to a second aspect of this application, a takeoff performance monitoring method based on dynamic safety margin calculation is provided, including means for performing the takeoff performance monitoring method based on dynamic safety margin calculation as described in the first aspect.

[0010] This overview is provided to introduce, in a simplified form, some of the concepts further described in the detailed description below. This overview is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. Attached Figure Description

[0011] To describe how the above and other advantages and features of the invention are obtained, a more detailed description of the invention, which has been briefly described above, will be presented with reference to specific embodiments of the invention shown in the accompanying drawings. It will be understood that these drawings depict only exemplary embodiments of the invention and are therefore not intended to limit its scope. The invention will be described and explained using the drawings and with the aid of additional features and details, in which: Figure 1a A schematic flowchart of a takeoff performance monitoring method based on dynamic safety margin calculation according to an embodiment of this application is shown.

[0012] Figure 1b A schematic flowchart of a takeoff performance monitoring method based on dynamic safety margin calculation according to a preferred embodiment of this application is shown.

[0013] Figure 2 This diagram illustrates the various stages an aircraft goes through during takeoff.

[0014] Figure 3 A schematic diagram of the various stages of the RTO distance during aircraft takeoff is shown. Detailed Implementation

[0015] This application provides a takeoff-related performance prediction and monitoring scheme based on runway length and dynamic safety margin calculation. It can perform takeoff and RTO-related verification schemes according to real-time aircraft status and adopt different takeoff performance monitoring mechanisms based on different safety margins. The scheme includes a mechanism that, based on real-time monitoring of the aircraft's current status, determines whether the remaining takeoff runway distance can meet the takeoff ground taxiing and RTO distance requirements under a specific safety margin. Specifically, if the takeoff performance monitoring fails, an alarm message is immediately triggered for the crew, prematurely aborting takeoff to ensure the aircraft can come to a stop. If the takeoff performance monitoring passes, important takeoff performance parameters, such as VSPD, are displayed and latched to avoid crew loss of situational awareness due to VSPD data transmission loss during takeoff acceleration in extreme scenarios. This reduces the probability of potential human error and also mitigates the adverse effects of lost takeoff parameters during critical phases of EASA's concern.

[0016] The setting of the safety margin coefficient requires comprehensive consideration of multiple factors, including technical factors related to the current status of each system of the aircraft, as well as environmental factors.

[0017] The impact of aircraft's own technical factors on takeoff performance is usually reflected in the following aspects: 1. Characteristics of the aircraft type, such as the thrust envelope characteristics of the engine, aerodynamic performance characteristics, and wind resistance of the aircraft surface coating; 2. Takeoff performance-related settings, such as takeoff weight, flap and slat settings, and takeoff thrust settings; 3. Performance degradation due to operating time, such as engine performance aging and thrust reduction due to increased operating time; 4. Performance degradation caused by system failures, such as critical control or power systems: spoiler failure, thrust reverser failure, etc.

[0018] The impact of environmental conditions on takeoff performance is usually reflected in: the temperature and air pressure of the takeoff airport (such as operation at high-altitude airports), wind speed and direction, runway conditions, and airport visibility (which may potentially affect the pilot's judgment and emergency response time).

[0019] In addition, personal factors of the pilot, such as flight time, can also affect their judgment and reaction time at critical points, potentially impacting the calculation of takeoff performance.

[0020] In other words, unlike existing takeoff performance monitoring schemes for existing aircraft models in the background art, this application can calculate corresponding safety margin coefficients based on the aircraft's real-time system status, external environmental factors during takeoff, and personal factors. By comparing whether the current available runway distance under different safety margin coefficients can meet the requirements for takeoff ground taxiing and RTO distance, it can determine whether the takeoff performance monitoring has passed the verification and monitor it in real time until the aircraft performs takeoff. The safety margin coefficients include at least a minimum safety margin coefficient and an optimal safety margin coefficient.

[0021] Specifically, when the aircraft performs takeoff and meets the optimal safety margin, some important takeoff performance parameters (such as VSPD) are displayed and latched. However, if the aircraft can only meet the minimum safety margin and cannot meet the optimal safety margin, a real-time takeoff performance monitoring mechanism is added to accelerate to the V1 stage to avoid performance deviations caused by unforeseen circumstances that could compromise takeoff safety. In this way, different takeoff performance monitoring mechanisms are adopted based on different safety margins, which simplifies the unnecessary performance monitoring workload under high safety margins and solves various safety issues existing in the current solution.

[0022] The following is combined Figure 1a This document describes a schematic flow of a performance monitoring and display method based on takeoff starting position according to an embodiment of the present application.

[0023] As shown in the figure, takeoff performance monitoring can be triggered manually or automatically. First, in step 102, relevant takeoff performance parameters are collected in real time. These parameters include, but are not limited to: aircraft current position and heading information, aircraft weight information, takeoff flap setting information, takeoff thrust setting information (thrust level, flexible temperature, etc.), takeoff reference speed information (VSPD), real-time aircraft system status information (including the status of anti-icing system, environmental control system, braking system, power system, etc.), takeoff external environmental information (including takeoff runway conditions, temperature, wind direction and speed, air pressure, takeoff airport visibility, etc.), crew personal information (such as the crew's current aircraft type flight experience / duration, etc.), and other flight parameter information necessary for takeoff.

[0024] Specifically, the performance monitoring process can be triggered automatically, such as when the takeoff thrust mode is activated during automatic flight, or after the crew sets the thrust lever angle to be greater than a certain angle (e.g., 59°), the data collection steps can be automatically started. Alternatively, the crew can trigger the process by pressing a corresponding button before takeoff acceleration. If the crew manually presses the corresponding button to trigger the process, the takeoff performance monitoring must continue until the aircraft meets the operational criteria for takeoff (e.g., based on the throttle lever angle).

[0025] When the process begins, the system can obtain information such as the aircraft's current position, heading, weight, takeoff flap settings, and takeoff thrust settings (thrust level, flexible temperature, etc.) from sources such as atmospheric data inertial reference systems, radio navigation systems, flight control systems, and flight control systems; obtain the current flap and slat settings and current thrust settings from sources such as flap control computers and position sensors, and throttle angle sensors; obtain information such as the braking system status, anti-icing system status, air conditioning bleed air system status, and CAS and dispatch information related to aircraft malfunction status from sources such as braking systems, environmental control systems, and central warning computers; and obtain crew personal information from sources such as communication data link systems and onboard information systems.

[0026] It should be understood that the information and data to be collected described above are merely illustrative examples and are not intended to limit the scope of this application. Technicians may obtain more or less information and data, or other flight parameters, from more or fewer data sources, as needed. These variations all fall within the scope of protection required by this application.

[0027] After the required data is collected, the process proceeds to step 104.

[0028] In step 104, the available runway distance, the takeoff ground distance required from the takeoff starting position to reach VLOF, the RTO distance required to accelerate to V1 and then stop from the takeoff starting position, and the safety margin coefficient of this takeoff are calculated based on the collected takeoff performance parameters.

[0029] 1) Takeoff ground distance refers to the horizontal distance an aircraft travels from the point where it begins acceleration (i.e., the "takeoff starting position") until it reaches its takeoff velocity (VLOF). Figure 2 As shown. The core calculation principle of the takeoff ground distance is based on acceleration integral, that is, calculating the distance required to accelerate from 0 speed to VLOF speed. It is affected by factors such as aircraft weight, engine thrust, runway friction and drag, runway slope and condition, wind speed / direction, air temperature and air pressure.

[0030] In practice, the takeoff performance monitoring system can use real-time collected takeoff performance parameters to automatically calculate the takeoff ground distance based on a predetermined RTO distance calculation model. Specifically, the takeoff performance parameters collected in step 102 may include the actual weight of the flight, airport barometric altitude reference, ambient temperature, target runway, takeoff thrust setting, takeoff flap positioning, and other relevant takeoff performance parameter data manually entered by the pilot in the electronic flight bag or flight management system, as well as system status parameters related to takeoff performance collected in real time by the takeoff performance monitoring system, such as power and braking system capabilities, wind direction and speed, etc. Subsequently, the corresponding calculation result will be generated as the takeoff ground distance for this takeoff based on the corresponding takeoff ground distance calculation model pre-built by the manufacturer.

[0031] 2) RTO distance, or the distance an aircraft travels before aborting takeoff, refers to the total horizontal distance an aircraft travels from its initial takeoff position, accelerating to decision speed V1, undergoing a crew decision (abort decision), and then applying maximum braking and reverse thrust until it comes to a complete stop. For example... Figure 3 As shown, the RTO distance comprises the distances of the acceleration phase, decision phase, and deceleration phase. The calculation of the RTO distance is influenced by factors such as aircraft weight, engine thrust reversers, runway friction and drag, runway slope and conditions, wind speed / direction, air temperature, and air pressure. Further considerations include the choice of V1 speed, the RTO distance itself, and whether braking thrust reversers or other capabilities have been downgraded or malfunctioned. For example, regulations (such as FAR / CS-25) require calculations to consider the most conservative "all-engine failure" scenario (all engines providing thrust reversers and idle thrust) or the critical "critical engine not operating" scenario. Furthermore, the system's reaction delay time (typically 2-3 seconds) must be considered; that is, the horizontal distance traversed by the aircraft during the decision phase can be calculated using the distance covered in 2-3 seconds of V1 takeoff.

[0032] Therefore, the calculation of the RTO distance first requires calculating the decision speed V1, which is the starting point for the RTO distance calculation. V1 can be calculated based on takeoff performance parameters such as aircraft weight, configuration, runway conditions, and ambient temperature. It is the critical speed that ensures a safe stop and continued takeoff within the remaining distance.

[0033] Next, the distance of the acceleration phase is calculated. The calculation method is similar to that for calculating the acceleration phase of the takeoff run, but the target speed is V1.

[0034] Next, the distance of the decision segment is calculated, as mentioned above, which can be calculated by gliding for 2-3 seconds in V1.

[0035] Next, the deceleration distance is calculated: this is the most complex part, requiring consideration of the negative acceleration after a series of measures, starting from V1, including applying maximum braking, deploying speed brakes, and using thrust reversers (if available). Negative acceleration primarily depends on the braking system's capability, the tire-runway friction coefficient, and the aircraft's weight. Calculations also need to be performed using integration or performance charts. As mentioned above, the deceleration distance, in addition to considering takeoff performance parameters, must also fully account for equipment degradation or failure. Therefore, if the aircraft experiences braking system degradation or thrust reverser failure before V1, the system needs to calculate the longest "required distance" based on the actual aircraft condition.

[0036] Finally, adding the three distances together will give you the RTO distance.

[0037] In practice, the takeoff performance monitoring system can use the real-time collected takeoff performance parameters to calculate the required RTO distance based on the established RTO distance calculation model.

[0038] 3) The current available runway distance refers to the remaining takeoff runway distance calculated based on the current aircraft position, minus the takeoff line displacement distance, i.e., the distance from the runway start point to the takeoff starting position. When takeoff performance monitoring is triggered automatically, the takeoff starting position can be determined when the flight crew begins monitoring takeoff maneuvers or pushes the thrust handle to TOGA (Takeoff Attention). In other words, when a takeoff maneuver or push-to-GA is detected, the GPS position of the aircraft's current takeoff starting position is obtained. Subsequently, the distance between the takeoff starting position and the runway start point can be obtained based on the distance relationship between the takeoff starting position and the runway start point. If takeoff performance monitoring is triggered manually by the flight crew pressing a button before the aircraft has entered the takeoff runway, the total runway length can be considered the current available runway distance.

[0039] 4) The safety margin factor for this takeoff refers to the ratio that must be met between the available distance of the current runway and the actual takeoff distance (the greater of the takeoff ground runway distance and the RTO distance). This factor can vary according to the airline's operational needs. In actual operation, at least a minimum safety margin factor must be provided. In addition, more than one safety margin factor can be provided, such as an optimal safety margin factor and a minimum safety margin factor.

[0040] The minimum safety margin factor is the minimum margin required to ensure takeoff safety, and can be defined as a fixed value according to the Civil Aviation Administration of China's operating regulations or the airline's regulations. For example, it can be uniformly set as a fixed factor of 1.15 regardless of runway or airport conditions. Alternatively, different minimum safety margin factors can be set according to runway or airport conditions, as shown in Table 1. Table 1: Examples of Minimum Safety Margin Factors in Different Application Scenarios

[0041] The optimal safety margin coefficient is calculated based on the minimum safety margin coefficient, taking into account the coefficient increments of various factors to maximize takeoff safety. In other words, it is the margin coefficient that considers all worst-case takeoff conditions. The optimal safety margin coefficient can be obtained by weighting at least three factors—technical factors related to the current real-time status of the aircraft's various systems, takeoff environmental factors, and crew personal factors—based on the minimum safety margin coefficient.

[0042] For example, the optimal safety margin coefficient

[0043] in, Fi and Fj These are two different factors; Ki is the single-factor sensitivity coefficient, which is the proportion by which the safety margin coefficient increases as the takeoff performance factor decreases. The single-factor sensitivity coefficient can generally be obtained through theoretical calculation or big data statistics. For example, compared with dry runways, wet runways usually reduce the friction between the tires and the ground, so the aircraft needs to travel a longer distance to reach the same speed with the same thrust. Through theoretical calculation, the proportion of the impact of runway dry and wet conditions on the safety margin coefficient can be obtained. The calculation of the pairwise synergistic influence coefficients for two synergistic factors, i.e. , This refers to the influence coefficient of two synergistic factors, meaning that if two influencing factors coexist, the effect will be greater than 1+1=2. Therefore, it is necessary to introduce... To further calculate its impact on the safety margin coefficient, the impact coefficient of the two synergistic factors can usually be obtained through theoretical calculations or big data statistics. The coefficient of influence of the three synergistic factors is the additional performance reduction caused by the synergistic effect of multiple factors. It is generally obtained through theoretical calculation or big data statistics. The system degradation or defect level is the quantification of the degree of system degradation or defect that will negatively impact takeoff performance factors.

[0044] Calculation example: The minimum safety margin factor is a fixed value of 1.15. Factor 1 (Technology): For example, if engine thrust decreases, F1=85; Factor 2 (Environment): Headwinds decrease, F2=95; Factor 3 (Individual): The crew's experience is slightly insufficient, F3=90.

[0045] Where, assume K1=0.3, K2=0.4, K3=0.1, =0.35, If the safety margin is 0.5, then the calculated optimal safety margin coefficient should be 1.15. (1+0.3) 0.15 + 0.4 0.05 + 0.1 0.1) (1+0.35) (0.15) 0.05 + 0.15 0.1+0.1 0.05) + 0.5 0.15 0.05 0.1) = 1.15 1.075 1.01, approximately 1.25.

[0046] In this example, the minimum safety margin is 1.15 and the optimal safety margin is 1.25.

[0047] Among them, K1 is the technical factor sensitivity coefficient, which is the basis for takeoff performance calculation. It is determined according to the characteristics of the aircraft itself and needs to refer to real-time status parameters and maintenance system status parameters (such as maintenance records, system continuous operation time, etc.). It is one of the more difficult factors to calculate.

[0048] K2 is the environmental sensitivity coefficient. Its calculation is relatively straightforward, requiring the crew to input the necessary parameters for the calculation, such as the temperature and air pressure of the takeoff airport (e.g., for high-altitude airport operations), wind speed and direction, runway conditions, and airport visibility (which may potentially affect the pilot's judgment and emergency response time).

[0049] K3 is the sensitivity coefficient for personal factors. This sensitivity coefficient accounts for less than K1 and K2. It mainly represents the potential impact of factors such as the crew's qualifications and the flight time of the aircraft type on the takeoff V1 decision, abort, and other operations, judgments, and emergency response time.

[0050] It should be understood that the above example only shows the optimal safety margin coefficient calculated based on factors 1, 2, and 3. In practical applications, as mentioned above, each type of factor actually has multiple parameters. Therefore, the final optimal safety margin coefficient value is generally obtained by fitting the optimal safety margin coefficients configured for different factors.

[0051] After completing the above four calculations, the process proceeds to step 106.

[0052] In step 106, the takeoff performance verification is determined based on the following conditions: Current available runway distance >= (the greater of the required takeoff distance and required RTO distance) Minimum safety margin factor? If the condition is met that "current available runway distance >= (required takeoff distance, required RTO distance) whichever is greater", then... If the minimum safety margin factor (i.e., the minimum safety margin condition is met) is met, the takeoff performance verification passes. If the monitoring process is automatically triggered (the automatic triggering logic can use the actual takeoff judgment point, indicating that the aircraft is performing takeoff), the process directly proceeds to the next step 108. However, if the monitoring is manually triggered, since manual triggering can occur before the aircraft performs takeoff, the above takeoff performance verification needs to be continuously monitored until the aircraft begins to perform takeoff before the process proceeds to the next step 108 to perform display latching and takeoff performance monitoring and judgment under the lower safety margin condition.

[0053] On the other hand, if the current available runway distance cannot meet the greater of the two requirements (required takeoff distance and required RTO distance). If the minimum safety margin factor is not met, the takeoff performance verification fails, and the process proceeds to step 114.

[0054] In step 114, the system triggers the corresponding alarm information, such as displaying the alarm message "RWY TOO SHORT" on the screen, which may be accompanied by voice or sound reminders.

[0055] Only when the available runway distance is greater than or equal to the larger of (required takeoff distance and required RTO distance) can the aircraft be guaranteed to stop safely within the runway end, regardless of whether takeoff is normal or aborted due to an emergency requiring RTO, without overrunning the runway. Considering various factors such as crew reaction time deviations, runway conditions, and system degradation, additional safety margins are typically required. For example, some regulations require a takeoff distance factor of 1.15. For wet or contaminated runways, even higher safety margins are needed. Furthermore, for high-altitude airports, considering engine performance limitations, additional safety margins are required. Therefore, these all demonstrate the necessity of adding a safety margin on top of the larger of (required takeoff distance and required RTO distance).

[0056] For the calculated safety margin coefficients, the minimum safety margin can be used to meet the minimum requirements of operating regulations. However, all safety margin calculations are based on predictions of existing events. The minimum requirements of operating regulations are usually formed based on big data rather than on a specific aircraft. Therefore, the calculation of the optimal safety margin coefficient can take into account the actual aircraft conditions and the performance degradation under the worst scenario to ensure the safe takeoff of the aircraft in this takeoff environment.

[0057] Therefore, if the current available runway distance cannot meet the requirement of (required takeoff distance, required RTO distance) whichever is greater. When the minimum safety margin factor is set, if the larger value is the takeoff runway distance, it indicates that the takeoff may fail due to insufficient takeoff distance or takeoff before reaching full takeoff speed, resulting in insufficient safe takeoff altitude. This could lead to problems such as colliding with structures at the end of the runway. Conversely, if the RTO distance is larger, it may result in insufficient braking distance, causing the aircraft to overshoot the runway before coming to a complete stop. In both cases, the system can issue a "RWYTOO SHORT" warning message, accompanied by voice or audio prompts.

[0058] On the other hand, as mentioned earlier, after the takeoff performance verification passes, if the monitoring is automatically triggered, such as when the aircraft is performing takeoff, the process can directly proceed to step 108. If the monitoring is manually triggered, the aircraft may not have performed takeoff at this time. In this case, the takeoff performance monitoring needs to continue until the judgment logic for the aircraft to perform takeoff is met (e.g., the throttle lever angle is greater than a specific value; this judgment logic for performing takeoff can be consistent with the automatic monitoring trigger condition setting, or it can be different). The judgment condition for the aircraft to perform takeoff can be, for example, the crew pushing the throttle lever to the TOGA position. If the takeoff performance verification still passes at this time, the process proceeds to step 108. In step 108, when the aircraft performs takeoff, it further determines whether the following conditions are met: Current available runway distance >= (the greater of the required takeoff distance and required RTO distance) Optimal safety margin coefficient When the optimal safety margin condition is met, proceed to step 110, where the system will display and latch the currently shown takeoff performance parameters. If the optimal safety margin condition is not met, proceed to step 112, where different takeoff performance monitoring mechanisms will be adopted based on the different safety margin coefficients that can be satisfied by the currently available runway length.

[0059] Specifically, in step 110, for aircraft that meet the above-mentioned optimal safety margin conditions, since the optimal safety margin has fully taken into account the factors of performance degradation or reduction during takeoff, monitoring can be discontinued after the display latch is displayed. In step 112, for aircraft that meet the minimum safety margin condition but not the optimal safety margin condition, the runway length requirement is relatively low compared to the optimal safety margin. Although this increases the applicable range of the takeoff runway for the aircraft, it potentially increases the unsafe risks during takeoff. Therefore, for such aircraft that only meet the minimum safety margin, in addition to display latching, takeoff performance monitoring (verification) must be continuously performed during the takeoff phase, such as when accelerating to V1 speed. If a situation occurs where the current available runway distance is greater than or equal to the larger of (required takeoff runway distance and required RTO distance), an alarm message should be triggered in a timely manner, indicating to the crew that the runway length is insufficient and considering immediately aborting the takeoff. It should be noted here that since aborting takeoff during operation can also potentially increase unsafe factors, the monitoring and judgment conditions for the takeoff phase are different from those before takeoff. Instead of adding a safety margin coefficient, the relationship between the current available runway distance and the larger of (required takeoff runway distance and required RTO distance) is directly judged. If the condition is met, the crew can still complete the takeoff mission normally.

[0060] The display latches the currently displayed takeoff performance parameters. The display latch does not need to latch all takeoff performance parameters, but only some important parameters, such as the wheel lift speed VR and takeoff safety speed V2 in VSPD. That is, if the VSPD parameters fail during takeoff acceleration, the VSPD at the time of verification can still be displayed.

[0061] In step 116, the display latch is held until the aircraft meets the display latch unlock conditions.

[0062] The display lock unlock conditions may include: After normal takeoff, reach a safe takeoff altitude of, for example, 35 feet; or The aircraft thrust handle setting angle is less than the set threshold; or The aircraft departs from its current takeoff runway.

[0063] The purpose of displaying latch and unlock conditions is to determine when the aircraft should exit takeoff mode. This determination can be based on, for example, the idle position, throttle setting threshold, and the aircraft's position. a. The aircraft aborts takeoff, ceases using TOGA thrust, and begins deceleration. This can be determined by thrust reduction, for example, by reducing thrust to the idle position and engaging engine reverse thrust (to achieve better braking effect), or to unlock earlier. Alternatively, it can be determined by the throttle lever angle falling below a certain threshold (e.g., both engines' TRA < 59°), indicating that TOGA thrust has been disengaged; or b. The aircraft has taken off normally and reached an altitude of 35 feet; or c. Based on the location data, it can be determined that the aircraft has left the current runway.

[0064] Once any of the above conditions are met, the displayed latched parameters can be unlocked, and the system can proceed to the automatic trigger logic for the next takeoff performance monitoring. However, it should be understood that the unlocking conditions described above are for illustrative purposes only and are not the only limitations. In practical applications, other conditions can also be used to exit the displayed latch.

[0065] In this way, by latching a valid takeoff reference speed display after the takeoff performance verification is passed, it can be ensured that the crew will not lose situational awareness due to the loss of relevant data during takeoff acceleration, or that the takeoff performance will not be insufficient due to delayed decision-making / wheel lift.

[0066] It should be understood that although the above embodiments mainly exemplify two types of safety margin factors: "minimum safety margin factor" and "optimal safety margin factor," technicians can develop more safety margin factors to provide more levels of safety monitoring for takeoff performance based on actual scenarios and needs.

[0067] In a preferred embodiment, such as Figure 1b As shown, step 104' may further include: calculating the difference between the aircraft's current heading and the runway heading based on the collected takeoff performance parameters.

[0068] The difference between the aircraft's current heading and the runway heading: First, the aircraft's current heading parameter can be obtained from the collected takeoff performance parameters. This parameter can generally be obtained from the aircraft's heading and attitude reference system. The runway heading, on the other hand, can be obtained from a runway database, such as 360°. Therefore, by comparing the aircraft's current heading with the runway heading, the difference between them can be obtained.

[0069] Subsequently, the judgment condition in step 106' can be further modified to be when the following conditions are met: a) Current available runway distance >= (required takeoff distance, required RTO distance) whichever is greater. Minimum safety margin factor; and b) The difference between the aircraft's current heading and the runway heading does not exceed a threshold range; If the takeoff performance verification is successful, the process proceeds to step 108 to determine the display and latching of takeoff performance parameters.

[0070] If any condition is not met, the takeoff performance verification fails, and the process proceeds to alarm step 114.

[0071] The threshold range can be set according to the actual configuration and requirements of the airport and aircraft. For example, it can be set to ±20°. That is, if the runway heading is 360°, then if the aircraft's current heading is within the range of 340° to 20°, it is considered not to exceed the threshold range; otherwise, it is considered to exceed the threshold range.

[0072] The purpose of setting the condition "the difference between the aircraft's current heading and the runway heading does not exceed a threshold range" is to prevent aircraft from flying in the wrong direction. Because the same runway has two numbers based on the takeoff direction (e.g., "09" and "27"), ATC assigns takeoff direction based on external factors such as wind direction and speed. Therefore, in practical applications, there is a very small probability that an aircraft may be on the correct runway but take off in the wrong direction. By introducing this condition, when such an error occurs, the system will send an alarm message "CHK RWY COND" to the flight crew.

[0073] Based on the above calculation using the safety margin coefficient, performance prediction and monitoring related to takeoff and aborted takeoff can be performed to avoid insufficient takeoff performance caused by taxiway errors, heading errors, etc., when entering the runway; and the currently input takeoff reference speed can be further verified.

[0074] Once the verification is successful, the valid takeoff reference speed display is latched, which ensures that the crew will not lose situational awareness due to the loss of relevant data during takeoff acceleration, or that the takeoff performance will not be insufficient due to delayed decision-making / wheel lift.

[0075] Therefore, the takeoff performance monitoring method based on dynamic safety margin calculation proposed in this application has the following advantages: 1) Safety margin coefficients can be calculated based on the technical factors of the current status of each system of the aircraft, takeoff environmental factors, and crew personal factors, and used for judgment of takeoff performance monitoring; 2) Takeoff performance monitoring can be triggered manually or automatically to predict and monitor takeoff and aborted takeoff performance, which can avoid problems such as incorrect taxiway entry or heading when the aircraft enters the runway and cause insufficient takeoff performance; and can further verify the currently input takeoff reference speed; 3) Different takeoff monitoring mechanisms can be developed based on different safety margin coefficients. This can effectively reduce unnecessary system complexity and computational load under higher safety margins, and can also continuously monitor takeoff performance under lower safety margins to ensure takeoff safety. 2) After the takeoff performance verification is passed, the system locks the valid takeoff reference speed display, which can ensure that the crew will not lose situational awareness due to the loss of relevant data during takeoff acceleration, or that the takeoff performance will be insufficient due to delayed decision-making / lifting of the wheel.

[0076] In another embodiment of this application, a takeoff performance monitoring system based on dynamic safety margin calculation is disclosed, the system including means for performing the takeoff performance monitoring method based on dynamic safety margin calculation as described above.

[0077] Although the techniques have been described using language specific to structural features and / or methodological actions, it should be understood that the solutions are not necessarily limited to the described features or actions. Rather, these features and actions are described as illustrative examples of how to implement these techniques.

[0078] The operations of the example processes are shown in separate boxes and are summarized with reference to these boxes. These processes are shown as a flow of logical boxes, each of which may represent one or more operations that can be implemented using hardware, software, or a combination thereof. In the context of software, these operations represent computer-executable instructions stored on one or more computer-readable media that, when executed by one or more processors, cause one or more processors to perform a given operation. Generally, computer-executable instructions include routines, programs, objects, modules, components, data structures, etc., that perform a particular function or implement a particular abstract data type. The order in which the operations are described is not intended to be construed as limiting, and any number of the operations may be executed in any order, combined in any order, subdivided into multiple sub-operations, and / or executed in parallel to implement the described process. The described process may be executed by resources associated with one or more computing devices, such as one or more internal or external CPUs or GPUs, and / or one or more pieces of hardware logic, such as FPGAs, DSPs, or other types of accelerators.

[0079] All of the methods and processes described above can be embodied in software code modules executed by one or more general-purpose computers or processors, and can be fully automated via these software code modules. These code modules can be stored on any type of computer-executable storage medium or other computer storage device. This code can also be packaged into corresponding computer program products. Some or all of these methods can alternatively be embodied in dedicated computer hardware.

[0080] Any routine description, element, or box in the flowcharts described herein and / or in the accompanying drawings should be understood as potentially representing a module, segment, or portion of code comprising one or more executable instructions for implementing a specific logical function or element in that routine. Alternative implementations are included within the scope of the examples described herein, wherein elements or functions may be removed or performed inconsistently with the order shown or discussed, including substantially synchronous or reverse order execution, depending on the functionality involved, as will be understood by those skilled in the art.

[0081] While different embodiments have been described above, it should be understood that they are merely examples and not limitations. Those skilled in the art will appreciate that various modifications in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, the breadth and scope of the invention disclosed herein should not be limited by the exemplary embodiments disclosed above.

Claims

1. A takeoff performance monitoring method based on dynamic safety margin calculation, comprising: a) Real-time acquisition of relevant takeoff performance parameters; b) Calculate the current runway available distance, takeoff ground taxiing distance, RTO distance, and the optimal and minimum safety margin coefficients for this takeoff based on the collected takeoff performance parameters. c) Determine whether the takeoff performance verification has passed based on the following conditions: The current available runway distance is greater than or equal to the larger of (takeoff ground distance and required RTO distance). Minimum safety margin factor; If the above conditions are not met, relevant alarm information will be triggered. If the above conditions are met, the takeoff performance verification will continue based on the real-time collected takeoff performance parameters until the aircraft begins to perform takeoff maneuvers, at which point the following steps will be executed: When an aircraft is taking off, if the condition is met that "current available runway distance >= (required takeoff distance, required RTO distance)", then the aircraft must meet the greater of these two conditions. If the condition of "optimal safety margin coefficient" is met, the currently displayed takeoff performance parameters will be displayed and latched, and the takeoff performance monitoring process will end. When an aircraft is taking off, if the condition is not met that "current available runway distance >= (required takeoff distance, required RTO distance)", the greater of the two conditions must be met. The condition of "optimal safety margin coefficient" must be met, but the condition of "current available runway distance >= (takeoff ground taxi distance, required RTO distance)" must be satisfied. When the condition of "minimum safety margin coefficient" is met, the takeoff performance verification will continue while the display latch is being performed until the aircraft reaches V1 speed; The minimum safety margin coefficient is the minimum margin coefficient that can guarantee takeoff safety, and is defined as a fixed value according to the Civil Aviation Administration's operating regulations or the airline's regulations. The optimal safety margin coefficient is a margin coefficient that takes into account all worst-case takeoff conditions. It is calculated by weighting at least three factors: the technical factors of the current state of each system of the aircraft, the takeoff environment factors, and the crew's personal factors, based on the minimum safety margin coefficient.

2. The takeoff performance monitoring method according to claim 1, characterized in that, The method further includes: If the following display latch unlock conditions are met, the displayed latched takeoff performance parameters will be unlocked: After normal takeoff, the aircraft reaches a safe takeoff altitude; or The aircraft thrust handle setting angle is less than the set threshold; or The aircraft departs from its current takeoff runway.

3. The takeoff performance monitoring method according to claim 1, characterized in that, Step b) also includes: The difference between the aircraft's current heading and the runway heading is calculated based on the collected takeoff performance parameters; Step c) requires the following conditions to be met for the takeoff performance verification to be considered passed: Current available runway distance >= (the greater of the required takeoff distance and required RTO distance) Minimum safety margin factor; and The difference between the aircraft's current heading and the runway heading does not exceed a threshold range.

4. The takeoff performance monitoring method according to claim 1, characterized in that, The takeoff ground roll distance refers to the horizontal distance traveled by the aircraft from the takeoff starting position until it reaches its takeoff speed (VLOF); and The takeoff ground taxiing distance is automatically calculated by the takeoff performance monitoring system using real-time collected takeoff performance parameters and based on a predetermined takeoff ground taxiing distance calculation model.

5. The takeoff performance monitoring method according to claim 1, characterized in that, The RTO distance refers to the total horizontal distance traveled by the aircraft from the takeoff starting position, accelerating to the decision speed V1, then undergoing crew decision-making, and finally applying maximum braking and reverse thrust until it comes to a complete stop; and The RTO distance is automatically calculated by the takeoff performance monitoring system using real-time collected takeoff performance parameters and based on a predetermined RTO distance calculation model.

6. The takeoff performance monitoring method according to claim 1, characterized in that, The current available runway distance refers to the remaining takeoff runway distance calculated based on the current location of the aircraft.

7. The takeoff performance monitoring method according to claim 3, characterized in that, The alarm information includes: If the condition is not met that "current available runway distance >= (takeoff ground distance, required RTO distance) is greater than the other", then the condition is incorrect. The condition of "minimum safety margin factor" will display "RWY TOO SHORT"; If the difference between the aircraft's current heading and the runway heading exceeds the threshold range, "CHK RWYCOND" will be displayed.

8. The takeoff performance monitoring method according to claim 1, characterized in that, The displayed and latched takeoff performance parameters include at least the wheel lift speed VR and takeoff safety speed V2 in the VSPD.

9. A takeoff performance monitoring system based on dynamic safety margin calculation, comprising means for performing the takeoff performance monitoring method as described in any one of claims 1-8.

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