Aircraft Arrival Time Control via Cruise Phase Speed Decoupling
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Solution Overview
Problem
Current aircraft time of arrival control methods are inefficient due to limited scope for speed adjustments during the cruise phase, leading to significant deviations between actual and estimated arrival times, which necessitate costly and complex descent speed adjustments.
Innovation Solution
Decoupling the cruise and descent phases of the flight plan allows for earlier and more significant speed adjustments during the cruise phase, reducing deviations and requiring fewer adjustments during descent by reconfiguring the speed scheduling logic in the Flight Management System (FMC).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If speed adjustments are limited during the cruise phase to maintain fuel efficiency, then fuel consumption is reduced, but time deviation from the scheduled arrival increases
Solution Approach 1:
The flight trajectory is divided into multiple segments (climb, cruise, descent) with different RTA control strategies applied to each. The cruise phase is further segmented into early cruise (allowing speed adjustments) and late cruise (maintaining fuel efficiency), enabling differentiated speed control that balances fuel consumption and arrival time across different flight phases
Solution Approach 2:
Speed adjustments are performed during the early cruise phase before the descent phase begins. By proactively correcting time deviations during cruise rather than waiting until descent, the system prevents accumulated time errors that would require complex and fuel-intensive corrections during the descent phase
2Measurement precision
If speed adjustments are made during the descent phase to correct time deviations, then arrival time accuracy is improved, but the complexity and cost of descent corrections increase
Solution Approach 1:
The system performs preliminary speed adjustments during the cruise phase to correct time deviations before descent begins. This proactive approach reduces the magnitude of corrections needed during descent, simplifying the descent control strategy and reducing its complexity
Solution Approach 2:
The FMC continuously monitors ETA and compares it with RTA, using this feedback to determine when speed adjustments are necessary. The system only initiates speed changes when the time deviation exceeds a threshold, avoiding unnecessary control actions and simplifying the overall control logic
3Ease of operation
If a single Cost Index is applied across all flight stages, then the control system is simple to operate, but the ability to optimize both fuel efficiency and arrival time is limited
Solution Approach 1:
The system segments the flight plan into distinct phases (climb, cruise, descent) and applies different RTA control strategies to each phase. This allows the FMC to optimize for fuel efficiency during climb and descent while allowing more flexible speed management during cruise, achieving better overall optimization without requiring a completely complex control system
Solution Approach 2:
Different control parameters and strategies are applied to different segments of the flight trajectory. The cruise phase allows for speed adjustments to correct time deviations, while climb and descent phases prioritize fuel efficiency. This localized optimization approach maintains operational simplicity while improving overall performance
Data Source
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AI summary
A method for controlling aircraft time of arrival at a flight trajectory waypoint decouples the various parts of the flight for flight plan, speed scheduling and trajectory predictions. Adjustments to the speed during a first cruise phase of the flight reduce the deviations between the actual and estimated arrival times throughout the flight, and particularly reduce the amount of speed adjustments necessary during the later descent phase.