Method and apparatus of automatically monitoring aircraft altitude

DETAILED DESCRIPTION An apparatus and method for automatically and independently determining aircraft altitude and alerting the pilot to deviations from a target altitude exceeding a specified tolerance.
The alerter comprising an altitude sensing means for sensing the present altitude of the aircraft.
The invention discloses three sources for altitude information namely, a self-contined sensor such as a pressure transducer, a Global Positioning System receive, or an altitude encoder.
A target entry means is used for entering the target altitude to which the present aircraft altitude is compared.
A computation means receives and processes the present aircraft altitude information from the altitude sensing means and the target altitude from the target entry means.
The computation means is operative to compare the present altitude to the target altitude and to compute the difference therebetween.
The computation means is also operative to compute the absolute value of the difference between the target and present altitudes to the tolerance value.
An indicating means signals an altitude alerting condition upon the detection of a condition wherein the absolute difference is larger than the tolerance value.
The altitude alerting apparatus may also comprise a display means for display of the present aircraft altitude information.
The target entry means may comprise a push-button electrically connected to the computation means such that upon depressing of the push-button, the target altitude is equated to the present aircraft altitude.
Alternatively, the target entry means may comprise at least one multi-position switch electrically connected to the computation means such that upon selection of one of the multipositions, a number representing the target altitude is entered into the computation means.
The altitude alerting apparatus may also comprise a means for inputting a variable tolerance window within which the absolute difference between the target altitude and the present altitude may vary without triggering an altitude alert condition