Leading Edge Slats Stall Margin Improvement
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Solution Overview
Problem
The accumulation of ice on an aircraft wing can reduce the stall margin, leading to increased drag, reduced lift, and a higher risk of stall during critical phases of flight, such as climb. Existing ice protection systems may not always be activated in time to prevent ice formation, especially during high pilot workload conditions like take-off.
Innovation Solution
The method involves automatically commanding the deployment of leading edge slats when specific conditions are met, such as exiting the initial climb phase, being in an en route phase, reaching or exceeding an altitude of 400ft, or when the aircraft speed is below a predetermined threshold. The slats are automatically retracted when the aircraft exceeds the deployment speed threshold or when the angle-of-attack falls below a predefined retraction threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ice protection systems are activated early to prevent ice accumulation, then the stall margin is maintained, but the pilot workload increases during take-off
Solution Approach 1:
The system enables the aircraft to automatically detect ice accumulation conditions and deploy slats without pilot intervention. The flight management system monitors flight parameters and automatically commands slat deployment when ice contamination is detected during climb phase, allowing the aircraft to self-correct the stall margin reduction caused by ice.
Solution Approach 2:
The system uses feedback from flight parameters (altitude, speed, angle of attack) and ice detection sensors to automatically adjust slat position. The flight management system continuously monitors the climb phase and responds to ice contamination conditions by deploying slats, creating a closed-loop control system that maintains stall margin without requiring continuous pilot monitoring.
2Reliability
If slats are deployed to improve stall margin during climb, then lift is increased, but drag increases
Solution Approach 1:
The system dynamically adjusts slat deployment based on real-time flight conditions and ice contamination detection. Rather than static deployment, the slats are automatically positioned according to the severity of ice accumulation and current flight phase, optimizing the balance between lift enhancement for stall margin and drag generation.
Solution Approach 2:
The system applies slat deployment selectively during the climb phase when ice contamination most affects stall margin. The automatic system determines the specific climb phase and applies slat configuration only when necessary, rather than continuous deployment, thereby limiting drag penalties to only when they provide the most benefit for stall margin.
3Speed
If ice accumulates on the wing, then the angle-of-attack for stall decreases, but the lift is reduced
Solution Approach 1:
The system detects ice accumulation during the climb phase and proactively deploys slats before the stall condition occurs. By detecting the presence of ice and automatically deploying slats in advance, the system prevents the reduction in stall angle-of-attack and maintains lift generation capability throughout the critical climb phase.
Data Source
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AI summary
A system and a method for improving a stall margin of an aircraft during a climb phase of flight are disclosed. In one embodiment, the method comprises using data indicative of a phase of flight of the aircraft and data indicative of an angle-of-attack, and automatically commanding a deployment of leading edge slats movably attached to wings of the aircraft when the following conditions are true: the aircraft is in a climb phase of flight; and the angle-of-attack equals or exceeds a predefined deployment angle-of-attack threshold value.