A conventional threat avoidance system installed in a host aircraft provides advice (e.g., advisories and/or alerts) to members of the flight crew so as to reduce the risk of colliding with other aircraft, colliding with terrain, or encountering adverse weather conditions. Advice is based on detecting aspects of the host aircraft, other aircraft, and/or weather conditions; predicting future positional relationships among the host aircraft, other aircraft, terrain as described in elevation maps, and/or weather conditions; and predicting the capability of the flight crew and the host aircraft to respond to the advice. Inaccuracies in detecting these aspects and inaccuracies in models of behaviors used for predictions have led to the use of numerical safe guards that result in inaccurate advice including what is colloquially referred to as “nuisance” advice.
Efforts to reduce the occurrence of nuisance advice have focused on reducing uncertainty in detecting aspects such as determining more accurate host aircraft altitude. Other uncertainties may be more significant, such as uncertainties in modeling host aircraft performance. Another approach adjusts the behavioral model of the host aircraft according to measured performance of the host aircraft during take-off. This too is unsatisfactory due to differences between a take-off scenario and a threat avoidance scenario. For example, one cannot assume that take-off will be attempted at full throttle or maximum climb angle as may be used to avoid collision. Knowledge of host aircraft performance at one throttle setting and climb angle may not be sufficient to reduce uncertainty in predicting performance at other throttle settings and climb angles. Knowledge of flight crew responsiveness during take-off may not be sufficient to reduce uncertainty in predicting responsiveness in reacting to advice.
It is highly desirable to reduce nuisance advice without compromising flight safety. A departure from the prior art is needed to further reduce nuisance advice. Without systems and methods of the present invention, nuisance advice will remain at undesirable levels, possibly contributing to distracting conditions for the flight crew or a tendency to ignore recurring advice which may result in loss of life and damage to property when a collision is not successfully avoided.