Cruise Vertical Profile Optimization Under RTA Constraints
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Solution Overview
Problem
Current flight management systems struggle to optimize the cruise vertical profile of aircraft while meeting required time-of-arrival (RTA) constraints, often prioritizing RTA speed profiles over fuel efficiency and considering only local step climb benefits rather than global trajectories, which can lead to increased fuel costs and reduced RTA success rates.
Innovation Solution
A system and method that integrate cruise optimization and RTA functions within a flight management system to plan and fly a cost-optimum cruise vertical profile, using the vertical degree of freedom to increase the window of achievable RTAs and adjust speed profiles in real-time to meet time constraints, thereby enhancing fuel efficiency and RTA success.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RTA speed profiles are prioritized to meet time constraints, then time-of-arrival reliability is improved, but fuel efficiency deteriorates
Solution Approach 1:
The patent merges the RTA speed profile function and cruise vertical profile optimization function into a single integrated function. This allows the system to simultaneously consider both time constraints and fuel efficiency when determining the aircraft trajectory, rather than prioritizing RTA speed profiles separately as in conventional systems. The integrated function optimizes both speed and vertical profile together to achieve both time reliability and fuel efficiency.
Solution Approach 2:
The patent utilizes the vertical dimension (altitude) as an additional degree of freedom to achieve RTA constraints while maintaining fuel efficiency. Instead of relying solely on speed adjustments in the horizontal dimension, the system optimizes the vertical profile (climb/descent steps) to create multiple achievable RTA windows, allowing the aircraft to meet time constraints without excessive fuel consumption by exploiting altitude variations.
2Device complexity
If only local step climb benefits are considered for cruise optimization, then device complexity is reduced, but fuel efficiency deteriorates
Solution Approach 1:
The patent extends the optimization scope from local step-by-step climb decisions to a global trajectory optimization that considers the entire cruise phase. By incorporating the vertical dimension throughout the complete flight path and using the integrated function to evaluate all possible climb/descent sequences globally, the system achieves superior fuel efficiency compared to local optimization approaches.
3Device complexity
If conventional separate RTA and cruise optimization functions are used, then device complexity is reduced, but RTA success rate deteriorates
Solution Approach 1:
The patent combines separate RTA and cruise optimization functions into one integrated function that simultaneously handles both objectives. This integration allows the system to evaluate the interaction between speed profile and vertical profile optimizations, resulting in a higher RTA success rate by considering both constraints together rather than separately as in conventional systems.
Data Source
AI summary
A system and a method for planning and flying a cost-optimal cruise vertical profile in combination with a required time-of-arrival (RTA) constraint. The method may be implemented as a single function in a flight management system (FMS). The FMS plans the aircraft trajectory with cruise vertical and speed profiles that are optimized to minimize flight cost (e.g., fuel burn) while meeting the time constraint. When appropriate under the circumstances, this integrated function is also able to degrade the cruise vertical profile in order to open the window of achievable RTAs and increase the RTA success rate. The method also monitors progress of the flight along the planned trajectory as actual flight conditions may differ from the forecasted flight conditions, and readapts the cruise speed profile when the estimated arrival time is deviating from the RTA constraint by more than a specified threshold.