Patent ID: 8209072

Claim:
A method to assist piloting an aircraft during a landing phase at an airport having a plurality of runways, the method comprising: a1) automatically determining, for each of the runways of the airport, the runway's orientation and coordinates of the runway's threshold; a2) repetitively computing, for each runway, the runway's threshold based on the coordinates and orientation determined for the runway; a3) automatically and repetitively checking whether a characteristic height, which depends on the current altitude of the aircraft and on the altitude of the airport, is located within a predetermined height-wise detection window, a3i) setting a Boolean value to 1 if the characteristic height is within the predetermined height-wise detection window, and a3ii) setting the Boolean value to 0 if the characteristic height is not within the predetermined height-wise detection window; a4) repetitively computing for each runway, only when the Boolean value is set to 1, an angular difference between the orientation of the runway and a straight line passing through the current position of the aircraft; a5) computing, for each runway, a cumulative average of all computed angular differences; a6) comparing all computed cumulative averages with all other computed cumulative averages; a7) selecting a runway whose cumulative average is lowest according to the comparisons; b) repetitively determining the current longitudinal position of the aircraft in a reference frame linked to the selected runway; c) upon the aircraft passing the computed threshold of the selected runway: c1) repetitively determining a longitudinal stopping position of the aircraft from the current longitudinal position, and c2) repetitively comparing the longitudinal stopping position to the length of the selected runway; d) applying maximum braking to the aircraft while the determined longitudinal stopping position is greater than the length of the selected runway, wherein: the angular difference is computed for any runway of index k, by taking into account an orientation θAMk which is computed from the following expressions: - ⁢ if ⁢ ⁢ sin ⁡ ( μ ⁢ ⁢ AC - μ ⁢ ⁢ THRk ) < 0 , ⁢ θ ⁢ ⁢ AMk = arc ⁢ ⁢ cos ( sin ⁡ ( λ ⁢ ⁢ AC ) - sin ⁡ ( λ ⁢ ⁢ THR ⁢ ⁢ k ) · cos ⁡ ( ρ ⁢ ⁢ AMk ) sin ⁡ ( ρ ⁢ ⁢ AMk ) · cos ⁡ ( λ ⁢ ⁢ THRk ) ) - ⁢ otherwise , θ ⁢ ⁢ AMk = 2 ⁢ π - arccos ( sin ⁡ ( λ ⁢ ⁢ AC ) - sin ⁡ ( λ ⁢ ⁢ THR ⁢ ⁢ k ) · cos ⁡ ( ρ ⁢ ⁢ AMk ) sin ⁡ ( ρ ⁢ ⁢ AMk ) · cos ⁡ ( λ ⁢ ⁢ THRk ) ) - ⁢ ρ ⁢ ⁢ AMk = 2 ⁢ R · arcsin ⁢ sin 2 ( λ ⁢ ⁢ THRk - λ ⁢ ⁢ AC 2 ) + cos ⁡ ( λ ⁢ ⁢ THRk ) · cos ⁡ ( λ ⁢ ⁢ AC ) · sin 2 ( μ ⁢ ⁢ THRk - μ ⁢ ⁢ AC 2 ) λTHRk and μTHRk are the latitude and longitude coordinates of the threshold of the runway of index k; λAC and μAC are the current latitude and longitude coordinates of the aircraft; and R is the radius of Earth.