Abstract: The present invention allows quick detection of actual hazardous windshears while ignoring the effects of normal turbulence. A system according to one aspect of the present invention comprises a signal processor configured to determine a presence of hazardous windshear based on: (a) whether a measured windshear is beyond a first predetermined threshold, and (b) whether a measured turbulence level is beyond a second predetermined threshold.

Abstract: The present invention allows quick detection of actual hazardous windshears while ignoring the effects of normal turbulence. A system according to one aspect of the present invention comprises a signal processor configured to determine a presence of hazardous windshear based on: (a) whether a measured windshear is beyond a first predetermined threshold, and (b) whether a measured turbulence level is beyond a second predetermined threshold.

Abstract: The present invention is a system for monitoring, storing, and reporting the accumulation of fatigue occurrences experienced by an aircraft. The system according to the present invention uses existing aircraft instrumentation to monitor fatigue occurrences. Data is collected on the magnitude and cycles of any turbulence encounters; magnitude and number of gloading accrued by aircraft maneuvering; the number of pressurization cycles that the aircraft has experienced; and the number of takeoffs/landing cycles that have occurred. These data are stored in electronic memory for later review by the flight crew or maintenance personnel. Additionally, the number of accumulated wing flap cycles and landing extensions/retractions may also be monitored to facilitate the maintenance operations of these two critical flight controls.

Abstract: Disclosed is a method and means for qualifying, quantifying and reporting aircraft turbulence encounters. The preferred embodiment provides an indirect method of measuring turbulence based upon the implementation of the well known equation:V.sub.ground =V.sub.air +V.sub.wind.Qualification of the turbulence encounter is implemented with a filter and quantification of the turbulence encounter is implemented with analog to digital conversion. Thereafter, a transmitter broadcasts the occurrence of the turbulence encounter to remote receivers tuned to receive the transmission.

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 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 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: 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: An aircraft guidance system for flying an optimal inertial flight path in a windshear encounter. Zero inertial flight path angle command is utilized as the basis for guidance commands for either horizontal or vertical windshears; the flight path angle command is constant regardless of the actual magnitude of the shear. The effect of the guidance law described is to provide a zero inertial flight path angle to prolong excitation of the aircraft's phugoid oscillatory mode. By utilizing inertial flight path angle derived from an inertial reference system, errors introduced by vertical gyroscope systems are eliminated and thus a very accurate flight path angle guidance law is produced. The described guidance control law maximizes the aircraft's time in the air during a windshear encounter. Protection against aircraft stall is also provided by using a computed variable maximum allowable angle of attack.

Abstract: 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.

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: 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: Apparatus for the automatically controlling aircraft descent to a computed descent flight path. At any point in the descent portion of flight, a path error signal is used to compute an incremental speed command that is algebraically summed with a nominal descent speed command to cause the aircraft to converge to or maintain the computed descent path. Means are provided to rate limit the algebraic addition of the incremental speed command so that the convergence rate to the path is virtually constant for a given path error and so that the relatively short term dynamics of accelerating and decelerating the aircraft which may cause oscillatory behavior are avoided. The use of an incremental speed command permits a simplified control law over the prior art and permits the direct control of the minimum and maximum allowable speeds of the aircraft without the necessity of switching control laws or additional monitoring.

Abstract: An improved method for the automatic acceleration of an aircraft to a preselected speed is described. At any point in the climb portion of flight, a capture of a computed altitude that is increased at a specified rate is performed to provide optimal acceleration.

Abstract: An apparatus for detecting jet engine failures during aircraft flight. Low and high speed rotor rotation velocities of one engine are compared with low and high rotor rotation velocities of other engines and the difference between them utilized to determine engine failure. Equivalent low speed rotor velocity of an engine is computed from the high speed rotor velocity of that signal. This computed value is compared with measured low speed rotor velocity of the same and of different engines. Differences between the computed values and the actual values are compared to a computed threshold, which allows for normal differences between engines, to determine the operational state of the engine. Additional engine testing is performed by comparing low speed rotor rotational velocity to a computer windmilling value for each engine.

Abstract: A cruise speed control apparatus for aircraft wherein small differences between the target Mach command and the actual Mach number of the aircraft are used to displace the aircraft from its reference altitude to either increase or decrease actual Mach number in the short term. Long term differences are corrected through a special isolation filter to separate the engine control loop and pitch control loop dynamics and an integration technique to adjust the automatic throttles about a thrust target for the commanded Mach.Large differences between the target Mach and the actual Mach or large changes in the commanded Mach are compensated for by a non-linear gain that effectively increases or decreases the target thrust to cause the aircraft to accelerate or decelerate to the commanded Mach.

Abstract: Deceleration control apparatus for an aircraft having an automatic altitude capture and hold system and an airspeed hold system, both systems controlled by controlling pitch attitude wherein during a descent from a higher altitude under airspeed-on-pitch control with throttle set at idle thrust, and at some existing negative altitude rate, a slower speed is commanded, a synthetic altitude based on the existing descent rate is computed and the attitude capture and hold system operation is switched into control in place of the airspeed on pitch control to cause the aircraft to flare toward the synthetic altitude. The resultant loss of airspeed, i.e., craft deceleration, during the altitude capture flare is monitored and when the commanded airspeed reduction is achieved, the airspeed-on-pitch control is resumed to thereby hold the commanded lower airspeed.

Abstract: An improved flight control system for initiating and thereafter controlling the automatic capture of a preselected altitude is described. At any point in the flight and in any autopilot pitch submode, the remaining time before an altitude capture is to commence is computed and used as a limiting signal such that the aircraft is precisely aligned with the commanded capture flight path when the capture maneuver commences thereby obviating mode to mode transients. The aircraft's altitude rate is continuously monitored during the capture maneuver and the flight path command is automatically altered between asymptotic and circular paths to assure that the acceleration normal to the flight path will not exceed a predetermined value while at the same time allowing a timely altitude capture.

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.