Aircraft Takeoff Rejection Control Using Acceleration Feedback
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Solution Overview
Problem
Current aircraft takeoff systems are prone to accidents due to errors in inputting takeoff parameters, such as weight and V-speeds, which can lead to incorrect acceleration and climbing capabilities, resulting in potential runway overruns and catastrophic consequences.
Innovation Solution
A system that automatically rejects takeoff if measured acceleration deviates from calculated values, using inertial sensors to compare estimated and actual longitudinal acceleration, and ensures the rejection occurs within a safe speed range to prevent runway excursions, by reducing thrust, applying brakes, and increasing drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If automatic takeoff rejection system is implemented to detect acceleration discrepancies, then safety is improved, but device complexity increases
Solution Approach 1:
The system continuously monitors actual acceleration via inertial sensors and compares it against pre-calculated expected acceleration values. When a discrepancy exceeds a threshold, the system triggers automatic takeoff rejection. This closed-loop feedback mechanism detects weight or configuration errors in real-time, improving safety without requiring complex manual procedures.
Solution Approach 2:
The flight computer automatically performs the rejection decision and executes the abort sequence without pilot intervention. The system uses its own onboard sensors and existing flight control systems to self-diagnose the unsafe condition and self-correct by initiating rejection, reducing the need for additional complex external systems.
2Reliability
If pilot manually monitors takeoff parameters to detect errors, then safety is improved, but pilot workload increases
Solution Approach 1:
The system transfers the monitoring and decision-making burden from the pilot to the flight computer. The automated system continuously checks acceleration parameters and independently determines when rejection is necessary, freeing the pilot from intensive manual monitoring while maintaining high safety standards.
Solution Approach 2:
The system provides automatic feedback to the pilot only when a discrepancy is detected, rather than requiring continuous pilot assessment. This reduces workload by eliminating the need for constant manual parameter checking while maintaining situational awareness through selective alerting.
3Loss of time
If takeoff rejection is performed at high speed, then response time is improved, but harmful effects increase due to runway overrun risk
Solution Approach 1:
The system continuously calculates expected acceleration throughout the takeoff roll, establishing a baseline before any discrepancy occurs. By having the rejection decision logic and thrust reduction systems pre-configured and ready, the system can execute rejection immediately upon detecting a discrepancy, minimizing response time while ensuring the aircraft is still within safe stopping distance.
Solution Approach 2:
The system applies counter-thrust and activation of reverse thrust before the aircraft reaches dangerous speeds. By initiating the rejection sequence immediately upon detecting acceleration discrepancies, the system prevents the aircraft from accelerating to speeds where stopping would result in runway overrun, thereby preemptively eliminating the harmful effect.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces pilot workload and ensures safe takeoff by autonomously aborting takeoff when discrepancies in acceleration are detected, preventing high-energy aborts and potential runway overruns, thereby enhancing safety and reducing the risk of accidents.
Implementation Method 1
an inertial sensor system to measure the actual longitudinal acceleration of the airplane
Implementation Method 2
controlling the thrust of the aircraft engines to abort the takeoff
Implementation Method 3
activating the wheel brakes
Implementation Method 4
controlling the aerodynamic surfaces to increase drag
Data Source
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AI summary
An aircraft includes a safe takeoff system that automatically and autonomously rejects a takeoff if actual measured acceleration deviates from calculations based on pre-flight parameters and the speed of the aircraft traveling down the runway is within a safe speed range to guarantee a successful low inertia rejected takeoff.