The invention relates to methods and devices for aircraft's safe operation and is embodied in the form of a method and system for informing a user, for example an aircraft crew and/or a flight controller, on the probable penetration of the aircraft into dangerous areas of the vortex shedding of vortex generators which are located near the aircraft at a forecast time when the aircraft passes through a simulated control plane situated at a preventive distance in the direction of motion of the aircraft, said distance being calculated on a basis of a sufficient forecast period so that the aircraft carries out a flight evasive manoeuvre. The preventive system defines the trajectory and intensity of the vortex shedding of the vortex generators, the co-ordinates of intersecting points of the vortex sheddings with a control plane, the geometric parameters of the dangerous areas thereof (26, 27) according to danger criteria specified by a user, forms a warning area (28) in said control plane, an area of the forecast positions of the aircraft (25) and dangerous vortex shedding areas (26, 27) at a forecast time, follows up the events of crossing the warning area (28) and/or the area of the aircraft forecast positions (25) associated with the dangerous vortex shedding areas (26, 27) and draws attention of the user to said event with the aid of display devices (16, 17) and a visualisation device (18).

A system (24) for detecting an air disturbance in front of an aircraft (10) has a controller (26) that is coupled to an image detector (40). Image detector (40) generates an image signal corresponding to heated air in front of the aircraft (10). The air in front of the aircraft (10) is heated by direct high energy beams such as microwave beams (16, 18) from a respective microwave antenna (12, 14). By monitoring the image, the presence of an air disturbance may be determined. Position adjusters (30, 32) may be used to adjust the position of the beams (16, 18) by controlling the position of antennas (12, 14). The position of the beam is preferably maintained a predetermined distance (d) in front of the aircraft (10) so that an evasive maneuver may be performed.

A first beam of light from a laser is split by a beam splitter into a reference beam and at least one second beam of light, the latter of which is directed from an optical head into an atmosphere. Light from the at least one second beam of light scattered by molecules or aerosols in the atmosphere is collected by a corresponding at least one telescope of the optical head as at least one light signal. The at least one light signal and the reference beam are simultaneously processed by different portions of a Fabry-Perot interferometer, and resulting fringe patterns are imaged onto a detector and processed by a data processor to determine at least one associated air data product.

At least one second beam of light from a first beam of light generated by a laser is directed into an atmosphere. Light therefrom scattered by molecules or aerosols in the atmosphere is collected by at least one telescope as at least one light signal, which together with a reference beam from the first beam of light are simultaneously processed by an interferometer, and resulting fringe patterns are imaged onto a detector adapted to output a resulting at least one signal responsive thereto. In various aspects: a data processor gates the signal to provide a range-responsive measurement; the light signal is multiplexed; a circle-to-line interferometer optic transforms an at least partially circular fringe pattern to a substantially linear fringe pattern; or a CCD detector provides for recording a range-resolved image by successively transferring charges from one adjacent row of photosites to another.