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. The use of an algorithm which may be dynamically varied as a function of aircraft position obviates the need for simulating by discrete windshear magnitude as in conventional predetermined windshear tables and minimizes data storage requirements.

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.

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.

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.

An aircraft guidance system for optimizing the flight path of an aircraft in the presence of a windshear maximizes the time the aircraft remains in the air and the distance traveled regardless of the magnitude of the windshear, in the presence of horizontal or vertical windshear components, while effectively minimizing excitation of the aircraft's phugoid mode. A flight path angle is commanded sufficient to clear any obstacle that may be found in the airport vicinity. For longitudinal or horizontal shears, a slightly positive constant flight path angle which is a function of the magnitude of the vertical wind is added to the slightly positive flight path angle command to produce a modified command that compensates for the decrease in flight path angle relative to the ground caused by the vertical wind. The system inhibits exceeding stick shaker angle of attack by reducing the command signal until the actual angle of attack is equal to or less than the stick shaker angle of attack.