Aircraft Landing Stopping Point Determination Using Segmented Deceleration
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Solution Overview
Problem
Current methods for determining the stopping point of an aircraft on a landing strip during landing are imprecise due to their complexity, making them unsuitable for integration into aircraft avionics with limited computing capabilities, leading to potential false alarms or incorrect evaluations of dangerous situations.
Innovation Solution
A dynamic determination method that calculates a first and second deceleration profile based on ground speed, using tables of average time and adapted deceleration profiles, incorporating residual or reversed engine thrust, drag, braking force, and mass of the aircraft, to accurately compute the stopping point position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If elaborate models are used to determine stopping position with high precision, then measurement precision is improved, but device complexity increases making them incompatible with certified avionics computers
Solution Approach 1:
The deceleration process is segmented into distinct phases (establishment phase and constant deceleration phase), with different calculation methods applied to each phase. This segmentation allows the use of simple constant deceleration assumptions for the majority of the stopping distance while accounting for the complex establishment phase separately, thereby maintaining precision without requiring complex models throughout the entire calculation.
Solution Approach 2:
The method changes the deceleration parameter from a variable (in elaborate models) to a constant (in the simplified method) for the constant deceleration phase. This parameter change simplifies the mathematical model significantly, making it compatible with certified avionics computers while maintaining adequate precision for safety alerts.
2Device complexity
If simplified methods with constant deceleration are used, then device complexity is reduced for avionics integration, but measurement precision deteriorates leading to false alarms or incorrect danger evaluation
Solution Approach 1:
The stopping distance calculation is divided into two segments: the establishment phase (from braking initiation to constant deceleration) and the constant deceleration phase. The simplified constant deceleration method is applied only to the constant deceleration phase, while the establishment phase is handled separately using simplified assumptions. This segmentation resolves the contradiction by applying simplicity where appropriate while maintaining precision where needed.
Solution Approach 2:
The method performs preliminary calculation of the establishment distance and establishment time before applying the constant deceleration formula. By pre-calculating these parameters and subtracting them from the total stopping distance, the method ensures that the simplified constant deceleration assumption does not compromise overall precision, thereby resolving the precision-deterioration issue.
3Reliability
If precise stopping point determination is implemented, then reliability of safety alerts is improved, but computing capabilities requirements increase beyond what certified avionics can provide
Solution Approach 1:
The method changes the deceleration parameter from a complex variable function to a simple constant value for the constant deceleration phase. This parameter simplification dramatically reduces computing power requirements while maintaining sufficient reliability for safety alert generation, as the constant deceleration phase constitutes the majority of the stopping distance.
Solution Approach 2:
By segmenting the calculation into establishment phase and constant deceleration phase, the method allows the use of computationally intensive precise models only for the brief establishment phase, while using simple constant deceleration assumptions for the longer constant deceleration phase. This segmentation achieves reliability without excessive computing power requirements.
Data Source
AI summary
A dynamic determination method for determining the position of a stopping point of an aircraft on a landing strip and related system includes determining a first table of average time from touchdown of the aircraft as a function of the ground speed, based on an average deceleration profile of the aircraft; determining a first deceleration profile adapted to the current conditions, based on an engine thrust computed for each ground speed from the average time determined in the first table; determining a second table of time adapted to the current conditions based on the first deceleration profile; determining a second deceleration profile adapted to the current conditions, based on an engine thrust computed for each ground speed from the time determined in the second table; and computing the position of the stopping point from the second adapted deceleration profile.