Patent ID: 7581441

Claim:
A method of protecting an aircraft in flight against clear air turbulence, the aircraft occupying a position P and moving horizontally at a speed V, a plane P H0 being the horizontal plane passing through P, comprising the following steps: performing at least one pair of evaluations of the air temperature T B , T C at two points B, C which have positions that are symmetrical relative to the plane P H0 ; performing at least one pair of evaluations of the horizontal air speed VH B , VH C at two points B, C; determining an air temperature gradient from the pair of evaluations of the air temperature T B , T C ; determining a horizontal air speed gradient from the pair of evaluations of the horizontal air speed VH B , VH C ; determining an index signifying a presence of clear air turbulence from the air temperature gradient and from the horizontal air speed gradient; repeating the preceding steps; Analyzing a trend over time of the index; when the analysis of the trend over time of the index and an analysis of the path of the aircraft indicate that the aircraft will pass through an area subject to clear air turbulence, taking at least one aircraft safety measure; and when a time analysis of the index and an analysis of the path of the aircraft indicate that the aircraft will leave an area subject to clear air turbulence, alerting a crew of the aircraft.