Patent ID: 8275495

Claim:
A method for monitoring the ability to navigate an aircraft during a phase of flight close to the ground, said aircraft using, for its navigation, positional information supplied by a satellite positioning system, the method comprising: a) selecting in a setpoint selection unit a setpoint value for a height parameter, which is used during said phase of flight; b) determining, by a threshold determination unit, an alarm threshold associated with the selected setpoint value; c) receiving automatically and repeatedly, by a receiver, a current error value corresponding to an estimated current error of a current vertical position of the aircraft, supplied by said satellite positioning system, and automatically comparing, by a comparator, each received current error value with said alarm threshold; d) emitting an alarm indicating a condition in which the current error value is above said alarm threshold e) determining, by an auxiliary determination unit, for each received current error value, a current auxiliary value expressed in the form of an achievable performance relative to said height parameter; f) displaying, on a display screen of the aircraft, the display screen having a scale graduated according to height values: a first characteristic sign representing the selected setpoint value; and a second characteristic sign representing illustrating the current auxiliary value; and g) emitting an alert when said second characteristic sign comes within a predetermined height value of said first characteristic sign, and showing the alert in visual format on the display screen; wherein: the alarm is emitted following a predetermined time after the alert is emitted if said setpoint value is not replaced by a new setpoint value.