US 7,581,441 B2Granted

Method and device for protecting an aircraft against clear air turbulence

AssigneeThales

InventorsHervé Barny, Jean-Claude Lehureau, Patrick Feneyrou

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Abstract

The invention relates to a method of protecting aircraft in flight against clear air turbulence (CAT). Consider an aircraft occupying a position P and moving horizontally at a speed V, a plane PH0 being the horizontal plane passing through P. According to the invention, the method includes performing at least one pair of evaluations of air temperature TB, TC at two points B, C which have positions that are symmetrical relative to the plane PH0. At least one pair of horizontal air speed evaluations are performed VHB, VHC at the two points B, C; An air temperature gradient is determined; A horizontal air speed gradient is determined; An index signifying a presence of CAT is determined; The preceding steps are repeated; A trend is analyzed over time of the index.

Claims20

Dependent claims

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 PH0 being the horizontal plane passing through P, comprising the following steps:

performing at least one pair of evaluations of the air temperature TB, TC at two points B, C which have positions that are symmetrical relative to the plane PH0;
performing at least one pair of evaluations of the horizontal air speed VHB, VHC at two points B, C;
determining an air temperature gradient from the pair of evaluations of the air temperature TB, TC;
determining a horizontal air speed gradient from the pair of evaluations of the horizontal air speed VHB, VHC;
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.

7 more elements

Device for protecting an aircraft in flight against clear air turbulence implementing a method according to one of the preceding claims, comprising:

an optical probe measuring device for performing at least one pair of evaluations of the air temperature TB, TC at two points B, C which have positions that are symmetrical in relation to the plane PH0, the position of the points (B, C) being defined relative to the position P of the aircraft;
an optical probe measuring device for performing at least two pairs of relative air speed projection measurements in relation to the aircraft (VRBG, VRBD), (VRCG, VRCD) at two measurement points (BG, BD), (CG, CD), respectively on a measurement axis linking P to each secondary measurement point, the measurement points (BG, BD), (CG, CD) belonging to a horizontal plane passing through the point B, C, the measurement points (BG, BD), (CG, CD) having positions that are symmetrical relative to the point B, C and are equidistant from P;
means for combining the pairs of speed projection measurements (VRBG, VRBD), (VRCG, VRCD) to evaluate the horizontal air speed VHB, VHC at the point B, C;
means for determining an air temperature gradient from a pair of evaluations of the air temperature TB, TC;
means for determining a horizontal air speed gradient from a pair of evaluations of the horizontal air speed VHB, VHC at the points B, C;
means for determining an index signifying a presence of clear air turbulence from the air temperature gradient and from the horizontal air speed gradient;
means for analyzing a trend over time of an index;
means for determining whether the aircraft is about to enter into an area subject to clear air turbulence;
means for taking an aircraft safety measure, when the aircraft is about to enter into an area subject to clear air turbulence;
means for determining whether the aircraft is about to leave the area subject to clear air turbulence;
and
means for alerting a crew of the aircraft, when the aircraft is about to leave an area subject to clear air turbulence.

9 more elements

Dependencies are inferred from the claim text.