Abstract: Method for signalling insufficient maneuverability of an aircraft according to which:in a preparatory phase: with the aid of a plurality of N flight configurations, the weighting coefficients between three quantities G1, G2, G3 are determined, representative respectively of the acceleration, the slope angle of the trajectory and the risk of stalling, coefficients such that the weighted sum of said quantities is less than a threshold when maneuverability is insufficient;in an in-flight utilization phase: said weighted sum is calculated and a signal signifying insufficient maneuverability is generated if said sum is less than said threshold.Application to controlling aircraft.

Abstract: A windshear guidance system for guiding an aircraft during a microburst windshear is provided. This system includes a time comparison subassembly, an airspeed comparison subassembly and a pitch command subassembly. The pitch command subassembly includes a calibrated air speed source, latch means connected to the calibrated air speed source, switch means connected to the latch means, and a pitch guidance command unit connected to the switch means.

Abstract: A microburst precursor detector samples radar returns from meteorological radar signal reflectors and processes the signal returns in a statistical manner to determine average radar reflectivity and to extract Doppler signal parameters. The vertical velocity in still air and the vertical velocity of the meteorological radar reflectors are respectively determined from the average reflectivity and the Doppler signal parameters. The difference between the two vertical velocities is taken to determine the vertical wind velocity. The vertical wind velocity and the average reflectivity are processed to predict the occurrence of a microburst.

Abstract: The apparatus of the present invention improved low-level wind shear alert system that provides an improved method of identifying the presence and locus of wind shear in a predefined area. This system enhances the operational effectiveness of the existing LLWAS system by mapping the two-dimensional wind velocity, measured at a number of locations, to a geographical indication of wind shear events. This system can also integrate data and processed information received from a plurality of sources, such as anemometers and Doppler radar systems, to produce low-level wind shear alerts of significantly improved accuracy over those of prior systems. In particular, the apparatus of the present invention makes use of the data and processed information produced by the existing Low-Level Wind Shear Alert System as well as that produced by the Terminal Doppler Weather Radar to precisely identify the locus and magnitude of low-level wind shear events within a predetermined area.

Abstract: The apparatus of the present invention improved low-level wind shear alert system that provides an improved method of identifying the presence and locus of wind shear in a predefined area. This system enhances the operational effectiveness of the existing LLWAS system by mapping the two-dimensional wind velocity, measured at a number of locations, to a geographical indication of wind shear events. This system can also integrate data and processed information received from a plurality of sources, such as anemometers and Doppler radar systems, to produce low-level wind shear alerts of significantly improved accuracy over those of prior systems. In particular, the apparatus of the present invention makes use of the data and processed information produced by the existing Low-Level Wind Shear Alert System as well as that produced by the Terminal Doppler Weather Radar to precisely identify the locus and magnitude of low-level wind shear events within a predetermined area.

Abstract: Apparatus for remotely sensing changes in the spatial temperature profile of a column of atmospheric air includes (a) collecting means for receiving the thermal radiation from a column of atmospheric air, and for directing it to intensity sensing means; (b) sensing means with a rotatably mounted interference bandpass filter together with means for rotating the filter for sequentially tuning to and sensing the intensity in said column of atmospheric air of at least two spectral regions in the 4.17 to 4.2 .mu.m region of the CO.sub.2 spectral emission band; and (c) means for detecting temporal changes in the relative intensity of the spectral regions.

Abstract: A method is provided for determining the humidity and temperature of atmospheric air at selected distances along a field of view by passive IR spectrometry. An IR spectrometer is provided. A plurality of IR power densities values received by the spectrometer along the field of view at a plurality of discrete, selected IR wavelengths are measured. A set of equations which equate the measured IR power density to functions of temperature and humidity at the selected wavelengths is provided. From the set of equations the temperature and humidity of the atmospheric air along the field of view at selected range segments along the field of view are calculated.

Abstract: An advance in-flight windshear detection system which utilizes a scanning mirror to direct infrared energy located in a three dimensional space in front of the aircraft which is divided into a plurality of variable columns, onto a linear array of photoconductive infrared detectors, the detector emitting a signal representative of the radiant energy at various points in said variable located columns, and a computer for generating a displayable representation of the air temperature in front of the aircraft, the computer further capable of interpolating and extrapolating the air temperatures in the three dimensional space based upon the known and or calculated lapse rate; and a display device for graphically displaying the air temperature in front of the aircraft and above the flight path vector so as to provide a more accurate indication of windshear which is less affected by the uncertainties arising from measuring air temperature in a typically more turbulent region along the flight path vector as the aircraf

Abstract: A method and apparatus for detecting specialized meteorological conditions such as a microburst and also the wind condition generated behind an aircraft known as wake turbulence. The method and apparatus of the present invention is designed to display the location of the microburst directly on the flight controller's monitoring screen with the flight controller then being able to so inform any pilot of an aircraft of the microburst so that the pilot can take evasive action. The display on the flight controller's screen is to be in color. The displaying of the microburst on the screen is to be by means of a computer which utilizes as inputs the conventional aircraft surveillance radar, weather radar and ground radar as well as additional inputs of wind direction and velocity information obtained from detection devices mounted directly adjacent to the aircraft runway and along the approach and take-off areas for the runway.

Abstract: A microburst precursor detector utilizes a multiplicity of radar beams and samples radar returns, in each beam, from meteorological radar signal reflectors and processes the signal returns in a statistical manner to determine average radar reflectivity and to extract doppler signal parameters. These parameters are utilized to determine a second set of parameters; average doppler frequency within each radar beam, doppler spectral spread within each radar beam, and the skewness of the doppler spectrum in each beam. The second set of parameters is processed to establish the existence of a microburst, predicted surface impact, time to impact, wind shear surface location and track, and the magnitude of the wind shear.

Abstract: The apparatus of the present invention improved low-level wind shear alert system that provides an improved method of identifying the presence and locus of wind shear in a predefined area. This system enhances the operational effectiveness of the existing LLWAS system by mapping the two-dimensional wind velocity, measured at a number of locations, to a geographical indication of wind shear events. This system can also integrate data and processed information received from a plurality of sources, such as anemometers and Doppler radar systems, to produce low-level wind shear alerts of significantly improved accuracy over those of prior systems. In particular, the apparatus of the present invention makes use of the data and processed information produced by the existing Low-Level Wind Shear Alert System as well as that produced by the Terminal Doppler Weather Radar to precisely identify the locus and magnitude of low-level wind shear events within a predetermined area.

Abstract: A wind shear alert system for low level horizontal wind shears is disclosed. The wind shear alert system is based upon a network of remote sensor stations placed near runways throughout the geographic area covered by an airport. An airport configuration file supplies numerous parameters related to the geometry and geography of the airport, as well as threshold values for divergence phenomena in the form of microbursts. Selected pairs, edges, and triples, triangles, of said network are monitored specifically to detect a divergence. Data from the various remote sensor stations is filtered to remove short term effects and adjust for missing data. A network mean is computed to which wind field measurement data and divergence analysis is compared. If a divergence in the form of a microburst or generic wind shear is detected, then the relative magnitude of the loss or gain in head wind to approaching aircraft is determined, as well as the location of the head wind.

Abstract: Performance of an aircraft ground proximity warning system can be improved, especially where the performance of the aircraft itself has been degraded by a factor such as wind shear, by extending Mode 1 and Mode 3 warning envelopes down to within five feet of the ground. Additional improvements in warnings can be made by monitoring flight path angle, stall margin, angle of attack and deceleration profile, when the aircraft is close to the ground.

Abstract: The apparatus of the present invention improved low-level wind shear alert system that provides an improved method of identifying the presence and locus of wind shear in a predefined area. This system enhances the operational effectiveness of the existing LLWAS system by mapping the two-dimensional wind velocity, measured at a number of locations, to a geographical indication of wind shear events. This system can also integrate data and processed information received from a plurality of sources, such as anemometers and Doppler radar systems, to produce low-level wind shear alerts of significantly improved accuracy over those of prior systems. In particular, the apparatus of the present invention makes use of the data and processed information produced by the existing Low-Level Wind Shear Alert System as well as that produced by the Terminal Doppler Weather Radar to precisely identify the locus and magnitude of low-level wind shear events within a predetermined area.

Abstract: A wind shear detector provides an alert to the pilot of an aircraft upon the occurrence of a sustained low-level increasing performance shear if the shear occurs for a sufficiently long period of time, even if the shear is of a relatively low magnitude. An integrator is provided to integrate signals representative of low-level increasing performance shears and to provide the alert if the accumulated energy caused by the shear exceeds a predetermined level. The integrated low-level shear signal may be combined with currently occurring shear signals and the alert generated if the combination of current increasing performance shear signals and the integrated shear signal exceeds a predetermined level.

Abstract: A ground proximity warning system for aircraft having flight path angle based warning criteria generates a warning in the event of an excessively steep flight path angle during an approach to a landing. The warning criteria are altered to provide an earlier warning upon the occurrence of a low intensity wind shear or a below glideslope condition. A below glideslope warning system that is biased as a function of decreasing performance shear is also provided. A descent rate based warning system usable above a predetermined altitude may also be provided to supplement the flight path angle warning system.

Abstract: A microburst precursor detector utilizes a multiplicity of radar beams and samples radar returns, in each beam, from meterological radar signal reflectors and processes the signal returns in a statistical manner to determine average radar reflectivity and to extract doppler signal parameters. These parameters are utilized to determine a second set of parameters; average doppler frequency within each radar beam, doppler spectral spread within each radar beam, and the skewness of the doppler spectrum in each beam. The second set of parameters is processed to establish the existence of a microburst, predicted surface impact, time to impact, wind shear surface location and track, and the magnitude of the wind shear.

Abstract: A windshear warning system having an adjustable threshold to avoid triggering nuisance windshear alerts wherein the magnitude and duration of the shear are not sufficient to endanger an aircraft that is flying a landing approach at greater-than-normal approach speed. The present invention provides for variable detection times in either a variable threshold windshear detection or a fixed threshold detection system. A measurement of angle or attack is used to deduce the aircraft's approximate weight from which a normal landing approach speed may be calculated. The difference between the computed landing approach speed and the actual approach speed is used to calculate an add-on differential to the windshear system detection threshold.

Abstract: The invention comprises a microburst detection and measurement system having a plurality of SENSTRANS units positioned at spaced intervals, each SENSTRANS unit monitoring humidity, wind speed, wind direction, barometric pressure, and temperature. The sensors transmit the observed weather conditions to a central data processing and display unit via RF, FM transmission. The data processing and display unit collects and assimilates the data to determine if the measured parameters indicate the likely presence of microburst or other weather hazards. If so, it issues a weather hazard warning both visually and audibly.

Abstract: An improved aerodynamic vane is used for sensing the angle of attack of an aircraft during yawed flight. Left and right sensors are rotatably mounted to opposite sides of the fuselage of the aircraft and rotate in the air flow to a position indicative of the angle of attack of the aircraft. Each sensor consists of an arm rotatably attached at one end to the aircraft with a vane at the other end of the arm, which vane is canted at an angle with respect to the axis of rotation of the arm. The vanes on the sensors on the opposite sides of the aircraft are both canted down or up as to cause the sensors to take similar angular positions during yawed flight.

Abstract: An apparatus and a method for detecting and indicating severe weather conditions such as wind shear and clear air turbulence includes a sensor for detecting the weather parameter of air temperature differential and a computer for comparing the parameter value with a stored constant value. The sensor can be an infrared scanner in an aircraft or on the ground. When the parameter value exceeds the constant value, a severe weather condition warning indication is generated by the computer as a visual and/or audio signal. The method and apparatus can also include sensor modules for detecting wind speed and direction, barometric pressure and air temperature to be compared by the computer. A steam generator can generate steam bubbles for detecting winds aloft with the infrared scanner or weather radar.

Abstract: Method and apparatus for detecting low altitude wind shear through the use of autocorrelation on the received and processed echo signals. Self Autocorrelation of echo signals and autocorrelation of echo signals from consecutive pulses are used to calculate the low altitude Doppler velocities over distance. In an alternate embodiment, autocorrelation of echo signals from alternate pulses is also required. Wind shear is calculated from low altitude Doppler velocity as a function of location.

Abstract: A method is provided for determining the speed of the mean wind with respect to the ground during the flight of an aircraft. At each time of rank i of a succession of n times spread out over a flight period, the modulus V.sub.i of the air speed of the aircraft and the three components S.sub.Ni, S.sub.Ei and S.sub.Vi of the ground speed of the aircraft are measured. Then, using the method of least squares, the system of n(n-1)/2 equations with three unknowns W.sub.N,W.sub.E and W.sub.V is solved:2(S.sub.Ni -S.sub.Nj)W.sub.N +2(S.sub.Ei -S.sub.Ej)W.sub.E +2(S.sub.Vi -S.sub.Vj)W.sub.V=S.sub.Nj.sup.2 +S.sub.Ei.sup.2 -S.sub.Ej.sup.2 +S.sub.Vi.sup.2 -S.sub.Vj.sup.2 +V.sub.j.sup.2 -V.sub.i.sup.2 (5)in which W.sub.N,W.sub.E and W.sub.V are the three components of the mean wind speed, during the flight period. In response to the components thus determined, the equipment of the aircraft which is sensitive to the wind, for example the firing equipment, is controlled.

Abstract: An instrument (10) is disclosed for an aircraft having a windshear warning system to vary the threshold alarm setting as a function of a thermodynamic property of the air and as a function of local geographic and seasonal conditions. Specifically, a function generator 16 and other circuitry is disclosed. The output from the function generator 16 and other circuitry is then added to a fixed threshold acceleraton signal to produce a threshold alarm signal which has a value that is a function of the temperature of the air, in a basic embodiment.

Abstract: The invention provides for the detection of both longitudinal and vertical windshears during the takeoff and landing phases of aircraft flight. Standard instrumentation available on many aircraft is used to calculate the aircraft's energy loss or gain by integrating the value of the longitudinal shear. When the energy loss or gain exceeds predetermined levels, appropriate annuciation is provided to the human pilot. The same standard instrumentation aforementioned is also used to calculate changes in the aircraft's specific energy rate, that is the aircraft's actual energy rate divided by the aircraft's weight, to determine the effect of vertical winds. Specific energy rate is calculated by integrating the difference between the aircraft's acceleration relative to the ground and its acceleration relative to the airmass in which it is flying.

Abstract: A method and apparatus for simulating a windshear. A vortex is modelled in terms of a family of concentric streamlines and the position of an aircraft is defined with respect to the vortex as the aircraft traverses a reference plane. Four or more vortices are used to generate streamlines which match those encountered in an actual microburst. Each vortex placed above the simulated ground level is matched by a vortex of equal strength but opposite rotation placed below the simulated ground level at a distance equal but opposite to the height of the vortex above the ground. Strengths, distance from the vortex center, and height of the vortex may be programmed by the user. The high degree of flexibility permits accurate reproduction of the winds generated by actual microbursts for testing and developing microburst detection devices.

Abstract: A method for producing a warning of the existence of low-level wind shear and an aircraftborne system for performing the method utilizes measured values of airspeed and temperature, to determine a temperature based hazard factor relating to the existence of a wind shear threat to the aircraft and to issue a warning whenever the hazard factor exceeds a predetermined threshold level based upon the performance characteristics of the aircraft. Temperatures may be sensed locally, such as by a resistive temperature sensor or, remotely, such as by an infrarred temperature detector. Furthermore, in accordance with preferred embodiments, an inertial reactive wind shear detector is utilized as an integrated safety measure. Moreover, the threshold level may be varied depending on such factors as aircraft altitude.

Abstract: An integrated, remote sensing and reactive detection system is provided for detecting and confirming the presence of hazardous microbursts, macrobursts, and windshears in the general flight path of an aircraft. An infrared remote sensing system is used to seek out, detect, and provide advanced alerts of thermal gradients ahead of an aircraft which correlate with windshear conditions. The measurement of atmospheric temperature is accomplished by a scanning, multi-spectral radiometer that sweeps an approximate 60 degrees path in front of the aircraft at about a 5 hertz rate. The radiometer employs two rows of detectors that are slightly offset resulting in two simultaneous measurements of temperature that are about 7 degrees apart in elevation angle.

Abstract: An apparatus for measuring the temperature lapse rate of the environment surrounding an aircraft in flight is described. The measured temperature lapse rate is compared with the dry adiabatic temperature lapse rate. If the measured temperature lapse rate is less than the dry adiabatic temperature lapse rate, a cautionary message is issued to the flight crew alerting them of the probability of microburst windshears. In addition, if the cautionary message has been issued and a rapid reversal of the measured temperature lapse rate occurs, a warning message is issued to the flight crew advising them of the probable penetration of a microburst windshear.

Abstract: A wind shear warning system monitors the flight path of an aircraft and wind shear in the vicinity of the aircraft and generates an advisory or cautionary message for the pilot based both on the magnitude of the wind shear and the flight path of the aircraft. When the aircraft is flying a normal flight path, a wind shear warning is generated only when relatively high negative wind shears are present. If the flight path of the aircraft is not normal, for example, if the aircraft is below the glide slope or descending too rapidly, a cautionary alert is given at lower values of wind shear. The alert or warning is selected to provide the pilot with information defining the nature of the hazard or potential hazard being encountered.

Abstract: A system for elaborating, on board an aircraft, an alarm signal in the event of a mini-tornado, wherebyan alarm threshold (.alpha.+.alpha.w) for mini-tornado is defined which is a function of the present incidence (.alpha.) of the aircraft, incremented or decremented by incidence equivalents (.alpha.w) corresponding to present and past winds and to present and past wind variations; andthe mini-tornado alarm is triggered off when the compensated present incidence (.alpha.+.alpha.w) exceeds a critical threshold, taking the aircraft configuration into account.

Abstract: An instrument (10) is disclosed for an aircraft having a windshear warning system to vary the threshold alarm setting as a function of a thermodynamic property of the air and as a function of local geographic and seasonal conditions. Specifically, a function generator 16 and other circuitry is disclosed. The output from the function generator 16 and other circuitry is then added to a fixed threshold acceleration signal to produce a threshold alarm signal which has a value that is a function of the temperature of the air, in a basic embodiment.

Abstract: A wind shear detection system compares air-speed with a composite signal derived from signals representative of longitudinal acceleration, normal acceleration, angle of attack and flight path angle to generate a shear signal. An enhanced version of the system is also compensated for roll angle, radio altitude and flap position. In a modified system, the accelerations are calculated along the velocity vector of the aircraft rather than along the horizontal axis to compensate for inaccuracies that could occur under extreme flight conditions such as high bank angle turns and dynamic maneuvers.

Abstract: The rate-of-climb indicator of this invention can indicate the existence of wind shear.

Abstract: An improved windshear warning apparatus for aircraft, responsive to both the magnitude of the wind shear and the allowable time the windshear can be tolerated at a given magnitude. The sensed magnitude is used to compute the allowable time before providing a windshear alarm. For large windshear rates, the allowable time is short; conversely for small windshear rates which exceed a threshold level, a longer time period is computed before an alarm occurs. Since a windshear rate must persist for the computed allowable time before activating the alarm, windshear rates that are above the threshold level for elapsed time less than the computed allowable time will not result in an enunciation, while high magnitude windshear rates of short duration will not cause false alarms since they do not exceed the computed allowable time.

Abstract: An improved wind shear warning system for aircraft. A wind shear signal representing wind shear as modified by the downdraft drift angle of the aircraft is used to provide a warning signal when the wind shear signal exceeds (negatively) a variable threshold. The threshold for the warning signal is modified in response to the pilot controlled excess of the airspeed of the aircraft over a reference airspeed during the approach to a landing so as to avoid unnecessary warnings. The threshold is further altered when the wind shear signal during approach indicates the high likelihood of a reversal of wind shear conditions.

Abstract: The present invention comprises a system for detecting windshear and associated downdraft effects when they are encountered in flight by an aircraft. The system includes an input unit (12), a first processing unit (14), a second processing unit (16), an output unit (18), and a pilot warning device (20). The input unit receives aircraft performance data from the instruments and/or flight systems on the aircraft and preconditions this data to produce a set of signals corresponding to various aerodynamic and inertial input parameters. The first processing unit differences signals representing the aerodynamically derived and inertially derived accelerations of the aircraft in order to generate windshear signals. These windshear signals are then corrected for pitch rate induced coriolis acceleration effects. The corrected signals are used to form a signals representing longitudinal windshear along the horizontal heading axis of the aircraft and the change in aircraft climb gradient due to longitudinal windshear.

Abstract: The present invention constitutes a system for generating an elevator command signal for directing a pilot in guiding his aircraft along a path effective for recovering from hazardous windshear conditions. The system includes a descending mode guidance subsystem (10), an ascending mode guidance subsystem (12) and a switching mechanism (14) for shifting between the two subsystems. The descending mode subsystem includes an acceleration generator (20), a flight path command generator (22), a flight path error generator (24), a descending mode pitch error generator (26), an airspeed control device (28) and a descending mode signal controller (30). These components are connected serially together and operate to form an elevator command signal corresponding to the acceleration required to halt the descent of the aircraft by a fixed altitude level.

Abstract: Windshear indicator system comprised of a plurality of individual windshear detection and indication devices (10) disposed to one side of and parallel to the landing approach and takeoff areas of an airport runway. Each device (10) has a wind velocity sensor (24) and a wind direction indicator (22). Wind speed information is visually displayed in an array of vertical lights (30-40) of one color. A circular pattern of second colored lights (50-64) is provided so that the upper half of the pattern shows head winds and the lower half indicates or displays tailwinds to warn of a windshear condition. A green "go" light (74) flashes with the upper half of the circular lights (50-64). A red "no go" light (76) flashes with the lower half of the circular array of lights to warn of tailwinds and a windshear condition.

Abstract: Method and apparatus for commanding an optimal flight path for an aircraft encountering a windshear condition. An airspeed rate signal equal in magnitude and opposite in sense to the windshear is applied to derive a variable rate of change of airspeed command for application to a flight director indicator. Limits are placed on the derived command such that the minimum allowable speed command is stick shaker speed and the maximum allowable speed command is the nominal speed in the absence of the windshear. The resultant command signal represents a true airspeed rate that yields an optimal flight path for the aircraft to exit the windshear condition.

Abstract: An aircraft performance instrument which provides a first indicator which represents the line of level flight of the aircraft and a second indicator representative of the maximum permissible angle of attack of the aircraft.

Abstract: A system particularly adapted for guiding aircraft through wind shear conditions includes: a thrust command control (10) for maintaining airspeed and groundspeed within a defined range; a detection system (12) for detecting and annunciating the presence of moderate and severe wind shear; and a pitch command system (14) which provides pitch command signals for optimum climb out from a wind shear condition.

Abstract: The invention provides for rapid response and reliable detection of vertical windshear during the takeoff and approach phases of flight. Standard instrumentation available on many aircraft is used to calculate the down-draft acceleration and its effect on the aircraft's performance capability. The invention utilizes inputs from vertical acceleration, true airspeed, pitch angle, and angle of attack sensors. The rate of change of vertical wind is derived from the sensed signals and used to determine the margin between the aircraft's present performance capability and the predicted performance capability at stick shaker speed.

Abstract: A wind shear detection and alerting system (30) compares inertially derived accelerations with air speed rate to provide a wind shear warning signal. Inertially derived accelerations are used instead of purely inertial accelerations because purely inertial systems generally require a vertical gyro. By utilizing angle of attack (.alpha.) and flight path angle (.gamma.) instead of pitch angle (.theta.) in the calculation, no vertical gyro signal is required and the system will be responsive to vertical as well as horizontal shear conditions. An enhanced version of the system is also compensated for roll angle (.phi.), with the roll angle being derived from the rate of change of heading (.PSI.) to avoid the need for a vertical gyro. The alerting system is capable of providing visual and aural warnings for a variety of wind shear conditions, such as, head shear, tail shear, head shear followed by tail shear and wind shear trend.

Abstract: An active, electro-optical display system for use on fixed-wing, land-based airport runways, is disclosed for remotely guiding a pilot during visual approach and landing of an aircraft. Conventional Microwave Landing System (MLS) ground-transmitted data is air-derived on board the aircraft and data-linked to a ground receiver to produce a continuous digital data signal indicative of aircraft slant range, elevation and azimuth relative to the desired landing position. The resulting data signal is electrically coupled to a signal processor governed in accordance with control guidance laws to produce three discrete signals indicative of the magnitude and direction of the descent rate error, the flight path acceleration, and the lateral drift rate of the aircraft relative to the intended landing area.

Abstract: A device for indicating that an airplane has reached a safe speed for take-off rotation. The device indicates when both the airspeed equals or exceeds a preselected minimum airspeed and the ground speed equals or exceeds the preselected minimum airspeed less a preselected margin.

Abstract: A windshear warning apparatus which separately compares a plurality of signals derived from horizontal and vertical inertial acceleration and air mass acceleration components to indicate incipient windshear. The compared signals are substantially equal under normal wind conditions but are significantly different under windshear conditions. A signal proportional to the product of the magnitude and rate of change of the total or resultant inertial acceleration of the aircraft is used to provide a warning of a significant windshear condition.

Abstract: An aircraft is provided with wind velocity measuring equipment which measures the wind velocity both (1) close to the aircraft and (2) at a considerable distance such as one-half mile or a mile away from the aircraft; and a large difference in these two measured velocities indicates dangerous windshear conditions. Either a warning signal is given to the pilot, or automatic control apparatus is actuated, to avoid crash conditions. A single pulsed carbon dioxide (CO.sub.2) laser velocimeter may be mounted in the aircraft for measuring both the close-in and the distant wind speeds. The laser optic focus is shifted between the near and far measurements, and the return signal is time gated to increase signal-to-noise ratio.

Abstract: A display for aiding the pilot of an aircraft in anomalous wind environments. Wind velocity components are measured by an instrument 11, processed by a computer 12 and a vector generator 17 and then displayed as a vector 34 on the display shown in FIG. 3. A signal F indicative of flap position selects a flight validated lift curve which is displayed as a lift curve channel 42. During normal wind conditions the cursor 35 marking the termination of vector 34 is in the channel of curve 42. However, during wind anomalies cursor 35 moves outside the channel. It then becomes the task of the pilot to control the aircraft such that cursor 35 will move back into the channel.

Abstract: An improved wind shear warning system for aircraft. A wind shear signal representing wind shear as modified by the downdraft drift angle of the aircraft is used to provide a warning signal when the wind shear signal exceeds (negatively) a variable threshold. The threshold for the warning signal is modified in response to the pilot controlled excess of the airspeed of the aircraft over a reference airspeed during the approach to a landing so as to avoid unnecessary warnings. The threshold is further altered when the wind shear signal during approach indicates the high likelihood of a reversal of wind shear conditions.