Method of operation of a navigational calculator

A method of operating a navigational calculator having an input device for use in entering navigational information that is required to make a navigational calculation and an output device for use in displaying navigational information, comprising:

• providing the values of a plurality of variables using the input device;
• first calculating the value of a navigational parameter using the values of said plurality of variables;
• changing the value of said navigational parameter determined in said step of calculating using the input device;
• identifying a selected variable of said plurality of variables used to calculate said navigational parameter;
• second calculating the effect of the change in value of said navigational parameter on the value of said selected variable of said plurality of variables using the values of said plurality of variables used in said step of first calculating, except for the value of said selected variables, and using the value of said navigational parameter determined in said step of first calculating;
• and
• displaying the value of said selected variable calculated in said step of second calculating using the output device.

A method of operating a navigational calculator having an input device for use in entering navigational information that is required to make a navigational calculation and an output device for use in displaying navigational information, comprising;

• displaying a plurality of navigational parameters associated with the selected mode using the output device;
• selecting one of said plurality of navigational parameters to be calculated by the navigational calculator using the input device;
• replacing the display of said plurality of navigational parameters with a display of all of the variables that are required to calculate the selected navigational parameter and the values associated with the variables using the output device, wherein the values are cleared;
• associating, following said step of replacing, a previously entered value with each of said plurality of variables in any order that is convenient using the input device;
• first calculating the value of said navigational parameter using the values of said plurality of variables;
• displaying the variables, the flight parameter, and the values associated with each of the variables and the flight parameter using the output device;
• changing the value of said navigational parameter determined in said step of calculating using the input device;
• identifying a selected variable of said plurality of variables;
• second calculating the effect on the value of said selected variable of said plurality of variables resulting from the change in value of said navigational parameter using the values of said plurality of variables used in said step of first calculating, except for the value of said selected variable, and using the value of said navigational parameter determined in said step of first calculating;
• and
• displaying the value of said one of said plurality of variables.