TAWS Precaution Alerting for Nuisance Warning Reduction
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Solution Overview
Problem
Conventional Terrain Awareness and Warning Systems (TAWS) issue nuisance alerts that are premature, irrelevant, or unnecessary, distracting pilots and reducing their situational awareness, as these systems do not consider the pilot's existing awareness and often require the same response as warning alerts, leading to increased workload and potential dismissal of critical alerts.
Innovation Solution
Implementing a method that provides a precaution condition before caution and warning alerts, using altitude signals to determine the existence of a precaution condition and displaying a threshold altitude on vertical situational displays, altitude tapes, or topographical displays, allowing for subtle visual and auditory indications to alert pilots of impending hazards without distracting them from critical tasks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TAWS reduces alerting tolerances and margins to decrease nuisance alerts, then the number of nuisance alerts decreases, but caution alerts become preambles to warning alerts and require the same response time, making the system less effective
Solution Approach 1:
The patent segments the alerting system into three distinct levels: precaution alerts (first level), caution alerts (second level), and warning alerts (third level). Each level has different response requirements and time margins, allowing pilots to gradually respond to increasing levels of terrain threat without being overwhelmed by nuisance alerts or forced to respond to precaution alerts with the same urgency as warning alerts.
Solution Approach 2:
The system performs preliminary action by issuing precaution alerts before caution and warning alerts. These precaution alerts provide advance notice of potential terrain conflicts, allowing pilots to take corrective action before the situation deteriorates to the point of requiring full warning alert response. This preliminary warning layer reduces the frequency of subsequent caution and warning alerts.
2Measurement precision
If conventional TAWS issues alerts based on objective algorithms and accurate sensors, then measurement precision is improved, but nuisance alerts increase because the system does not consider pilot situational awareness
Solution Approach 1:
The patent applies local quality by providing different types of alerts (precaution, caution, warning) based on the specific local situation and level of terrain threat. Rather than using a single uniform alert type for all terrain conflicts, the system tailors the alert characteristics to the specific situation, providing subtle visual and auditory indications for early-stage threats and more urgent alerts for immediate dangers.
Solution Approach 2:
The system changes parameters by introducing a new alert type (precaution alert) with different characteristics than traditional caution and warning alerts. These parameter changes include different visual display characteristics, different auditory signals, and different response time requirements, allowing the system to communicate varying levels of urgency without generating excessive nuisance alerts.
3Loss of information
If conventional TAWS provides caution and warning alerts, then pilot awareness of terrain hazards is improved, but pilot workload increases and pilots may ignore or turn off the equipment
Solution Approach 1:
The system uses periodic action by issuing alerts only when specific terrain threat conditions are met, rather than continuously alerting. The precaution alert system periodically monitors terrain proximity and issues alerts only when the aircraft approaches predefined threshold margins, reducing unnecessary continuous alerts while maintaining situational awareness.
Solution Approach 2:
The patent applies partial action by providing subtle visual and auditory indications for precaution alerts rather than full-scale warnings. This partial alerting approach provides sufficient information for pilots to maintain awareness of potential hazards without requiring the same level of immediate response as critical warning alerts, thereby reducing workload while maintaining safety.
Data Source
AI summary
Systems and methods provide a precaution in an aircraft equipped with a terrain avoidance warning system (TAWS). The precaution is provided before a caution and a warning are issued by the TAWS for a subsequent condition to a precaution condition. The systems and methods determine an existence of the precaution condition at least partially in response to an altitude signal and provide a line on a display indicative of a threshold altitude in response to the precaution condition or a bar on an altitude tape of a primary flight display. The line is between a representation of the aircraft and a representation of terrain. The threshold altitude is an altitude at which a caution is issued by the TAWS.