Aircraft Stall Warning System Icing Adaptation
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Solution Overview
Problem
Existing aircraft stall warning systems lack precision in determining the stall angle, especially in varying flight environments such as icing conditions, which can lead to unnecessary or missed stall warnings.
Innovation Solution
A stall warning system that selects between different calculation criteria based on the icing state of the aircraft, using icing flags and sensors to determine the presence of icing, and adjusts the stall angle calculations accordingly to issue accurate warnings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single fixed stall angle criterion is used for stall warning, then the warning system is simple to operate, but the measurement precision of stall angle determination deteriorates in varying flight environments such as icing conditions
Solution Approach 1:
The patent implements dynamic selection of stall angle calculation criteria based on real-time flight conditions. The system switches between different calculation methods (Criterion A for non-icing, Criterion B1 for immediate post-takeoff icing, Criterion B2 for later-stage icing) according to the aircraft's operational state, making the warning system adaptive rather than static. This resolves the contradiction by allowing high precision through multiple criteria while managing complexity through condition-based selection logic.
Solution Approach 2:
The patent changes the parameters used for stall angle calculation based on flight conditions. Instead of using a fixed criterion, the system adjusts the calculation parameters (selecting different criteria with different stall angle thresholds) according to icing state and flight phase. This enables precise stall angle determination across varying environments while maintaining operational simplicity through automated parameter selection.
2Reliability
If stall warning is issued based on a conservative low stall angle threshold, then safety is improved, but unnecessary warnings increase during normal flight operations such as takeoff
Solution Approach 1:
The patent segments the flight operation into distinct phases with different stall angle criteria: non-icing flight (Criterion A), immediate post-takeoff icing (Criterion B1), and later-stage icing (Criterion B2). By dividing the operational envelope into segments with appropriate thresholds, the system ensures safety when needed while avoiding false warnings during normal operations like takeoff where Criterion B1 applies with higher acceptable angles.
Solution Approach 2:
The patent applies different quality standards (stall angle thresholds) to different flight conditions. Instead of using a uniformly conservative threshold everywhere, the system applies locally appropriate criteria: less conservative thresholds during controlled phases like takeoff (Criterion B1) and more conservative thresholds when icing is present in later flight stages (Criterion B2), optimizing both safety and reduction of false warnings.
3Reliability
If the stall warning system does not account for icing conditions, then the device complexity is reduced, but the reliability of stall warning deteriorates in icing environments
Solution Approach 1:
The patent prepares multiple calculation criteria in advance (Criterion A for non-icing, Criterion B1 for immediate post-takeoff icing, Criterion B2 for later-stage icing) and selects the appropriate one based on detected icing conditions. This preliminary preparation of multiple criteria enables reliable stall warning in icing environments without requiring complex real-time calculations, managing device complexity through pre-configured selection logic.
Data Source
AI summary
To provide a warning system that can issue a stall warning taking a flight environment into account. The warning system according to the present invention is a warning system for an aircraft, for issuing a warning in the case where there is a possibility of the aircraft stalling, and includes a selecting section for selecting one of two or more calculation criteria based on an icing state of the aircraft, a calculating section for calculating a stall angle based on the selected calculation criterion, and a warning section for comparing the calculated stall angle with a current angle of attack of the aircraft and issuing a stall warning if the current angle of attack exceeds the stall angle.