Abstract: A precision equivalent landing system. In one embodiment, a position determining system is coupled to an aircraft. The position determining system generates lateral position information of the aircraft with respect to a landing approach path. An altimeter is also coupled to the aircraft. The altimeter generates vertical position information of the aircraft with respect to the landing approach path. A graphic display disposed within the aircraft concurrently displays a visual representation of the lateral position of the aircraft with respect to the landing approach path and the vertical position of the aircraft with respect to the landing approach path. In so doing, the present invention provides both relative position and altitude of an incoming aircraft with respect to a landing approach path. Thus, the present invention provides a precision equivalent landing system without requiring the equipment and expense associated with ILS or FAA MLS precision landing systems.

Abstract: An apparatus (700) for inhibiting operation of an electronic device (702) during take-off and landing of an aircraft (802) has a sensor (704) that measures a lateral acceleration. A control circuit (706) is coupled to the sensor (704) and has an output (708) coupled to the electronic device (702).

Abstract: An aircraft display system positions a synthetic runway which is properly aligned with a target runway even during crosswind approaches. The relative position of the target runway is computed in a manner which reduces the accumulated error associated with previous systems. The lateral deviation rate of the aircraft relative to the extended centerline of the target runway is computed from data provided by various aircraft navigation and sensor systems. A track error angle representative of the difference between the extended centerline of the runway and the ground track of the aircraft is computed from the lateral deviation rate and ground speed. Runway bearing relative to ground track is computed from the track error angle and lateral deviation angle. Compensating runway bearing relative to ground track with drift angle yields a runway bearing relative to aircraft heading which is useful for positioning a synthetic runway on a display.

Abstract: An aircraft landing determination apparatus and method for determining landing status of an aircraft by tracking arriving aircrafts and providing a unique runway assignment therefor. The aircraft landing determination apparatus includes a target processor, a track administrator, and a track reporter. The target processor culls multiple target tracks from a target data transmission provided by a target sensor. The track administrator receives the target tracks, selects at least one arrival track therefrom, and allocates a unique runway assignment to each arrival track. The track reporter receives the arrival track and runway assignment, prepares a track report thereabout, and transmits the track report to a position monitoring apparatus.

Abstract: A relative GPS landing system is provided for approach and landing of aircraft where an accurate site survey of the GPS platform is unavailable. Data containing information on all GPS satellites in view is uplinked from a ground station to an aircraft. A relative solution is derived at the aircraft. Based upon the calculated solution, aircraft guidance signals are generated for approach and landing of the aircraft at a desired point.

Abstract: This device relates to assistance in the piloting of an aircraft or helicopter in conditions of poor visibility, at the landing stage, during the final approach before touchdown. In case of poor visibility, the landing operations are facilitated by ILS radioelectrical installations that enable an automatic approach to the runway threshold. All that remains to be done is to perform a flare-out for touchdown which has to be done in a certain zone at the start of the runway. It happens, in the event of poor visibility, that this touchdown zone is difficult to assess. This causes risks of overshooting. The disclosed device is aimed at putting out an alarm in the event of overshooting of the nominal touchdown zone.

Abstract: A system is provided which permits a display of ground conditions to the pilot through the use of a forward looking sensor set and uses signals generated from the aircraft to simulate ground aid signals which are used for automatic landing of the aircraft. General flight path angle and course aim point corrections are made from the cockpit of the aircraft and are adjustable as the flight progresses. Most of the systems today that have fixed path capability to ground intercepts are based on ground installed equipment. This system can establish the inertial flight path track internally to the aircraft and provides an automatic landing system which allows the pilot to concentrate on the visibility of the forward scene to confirm the safe progress of the landing.

Abstract: Disclosed is a flight management computer modification that provides a pilot of an aircraft with a list of alternate landing destinations at which he can land the aircraft in case of an emergency on board or due to some reason why he cannot land at an intended destination. Each of the alternate landing destinations is displayed with data regarding the distance between the aircraft's present position and each of the alternate destinations, the estimated time of arrival to fly the aircraft to each of the alternate destinations and an estimate of the fuel remaining on board the aircraft if the aircraft were to land at the alternate destinations. The data allows the pilot to compare the benefits of landing at one of the alternate destinations versus landing at another. The dam is calculated assuming a direct flight from the aircraft's present position to the alternate as well as assuming a missed approach at the intended destination and a flight from the intended destination to the alternate landing destination.

Abstract: The invention provides a system for determining the spatial position of a moving object and for guiding its movement, which system comprises a triangular arrangement of three light sources attached to the moving object and facing guidance device, electrooptical sensing device comprising an area imaging device and an image processing computer located at a position facing the moving object, there being provided a guidance computer connected to the image processing computer, and radio-communication device for the exchange of signals from and to said moving object. As an alternative the three light sources can be provided at the ground station and the other components of the system being attached to the moving object, there being provided communication device between said station and object. The system is of special value for guiding manned and unmanned aircraft.

Abstract: An aircraft upon approaching a runway for a landing receives a "measurable signal" from a transmitter located at the far end of the active runway. The strength of this "measurable signal" is indirectly proportional to the distance between the aircraft and the transmitter. After this signal strength is converted to digital data, a computer uses this distance in conjunction with preprogrammed performance characteristics of the aircraft to make a "safe" or "unsafe" decision. This decision is communicated to the pilot by means of a special meter on the instrument panel. The "safeness system" may be coupled to the aircraft's automatic braking system to provide a correct amount of deceleration. If properly enabled, this "safeness system" will initiate a go-around for another try at the landing should the current landing attempt be unsafe. A similar procedure would also abort a takeoff should the aircraft not reach rotation speed in time to clear an obstacle at the end of the runway.

Abstract: Disclosed is a method of and apparatus for processing flight control signals in an automatic landing system so that automatic landings can be executed within the bounds of current certification requirements (Category III weather minimums) and in a manner that in effect emulates standard manual landing procedures. Included is provision for introducing engine-out sideslip that insures that the automatic landing approach and touchdown is made with the aircraft wings level or with the upwind wing low. Also provided is the generation of rudder and wheel (aileron) compensation for lateral ground effects that occur during a landing with sideslip when the aircraft altitude is approximately one wingspan or less. Provision also is made for rudder control to offset yawing moment that occurs when the thrust of the operative engines is retarded prior to touchdown.

Abstract: Disclosed is a method of and apparatus for generating a signal representative of aircraft gear altitude after the flare maneuver is initiated in an automatic landing procedure. In accordance with the invention, the gear altitude signal is produced by complementary filtering of the aircraft gear altitude signal and the aircraft inertial vertical acceleration signal, with the complementary filter frequency being varied so that the aircraft filtered gear altitude signal primarily is produced on the basis of the vertical inertial acceleration signals prior to the time at which the aircraft reaches the runway threshold and is primarily produced on the basis of the aircraft gear altitude signal after the aircraft crosses runway threshold. The result is the reduction of the filtered gear altitude signal variation that can be caused by irregular terrain along the landing approach path while maintaining signal sensitivity to runway slope and runway slope variation.

Abstract: A flight control system of a turboprop airplane includes electronic controlled engines, which are governed by a manual operating device for setting the engine power in order to obtain a certain airspeed, a device for selecting a desired airspeed, and an engine control system for computing and controlling the required engine torque and speed as a function of ambient and engine conditions, the selected engine speed and the setting of said operating device. For automatically controlling the engine speed during the final approach to an airfield, the system includes an electronic approach speed control unit of which the adjustment signal influences the engine control device keeping the speed of the airplane during approach at a selected value whereby said manual operating device has a fixed setpoint. This electronic speed control unit may be carried out as an add-on device for retrofitting on a flight control system.

Abstract: When an aircraft is operating in an asymmetrical flight condition, such as during a landing decrab maneuver or during inflight engine out, the pilot is normally required to make precise compensatory roll control inputs to keep the aircraft moving along its original track angle. The pilot is relieved of this compensatory roll control task by providing a control system which automatically banks the aircraft to maintain the flight of the aircraft along the selected track angle while in the asymmetrical flight condition. Further adjustments in the bank angle of the aircraft are made automatically by a track angle feedback control system so that the aircraft remains on the selected track angle even when subject to external disturbances such as crosswind gusts and shear.

Abstract: This invention provides a flare control modification for pilot-in-the-loop aircraft maneuver command electronic flight control systems. During flare, pilot pitch control inputs are interpreted as incremental pitch attitude commands. The flare control modification allows conventional piloting technique (i.e., pitch controller pull-and-hold) to be used during flare, while retaining the benefits of maneuver command system masking effects of gusts, winds, wind shear, and variations in airplane weight, balance, and aerodynamic configuration.

Abstract: A precision approach control system designed to control the approach of an aircraft during landing to provide a more stable and easier mode of landing during critical landing situations, such as during the landing of an aircraft on an aircraft carrier. During operation, when the aircraft is subjected to vertical or horizontal winds or wind shear, the system controls the aircraft to maintain the inertial flight path angle constant which essentially defines operation in the precision approach control mode. In one disclosed embodiment, the precision approach control system changes the controller in the cockpit that is normally the pitch rate command stick controller during a Power Assist landing into a flight path angle rate controller. The autothrottle system for the aircraft is utilized to maintain the aircraft at a predetermined angle of attack during landing in the precision approach mode.

Abstract: A take-off performance monitor uses a sensor to produce a movement signal proportional to the movement of an aircraft during a take-off roll and, for each take-off, historical data is generated and stored based on the movement signal. An analyzing unit of the monitor uses the historical data and current conditions to calculate a reference take-off distance, reference acceleration data and reference velocity data. This information is output to the pilor to facilitate his judgment as to the adequacy to take-off performance. In the preferred embodiment, the analyzing unit utilizes five samples of acceleration and velocity during a take-off roll to solve an equation for five constants that are indicative of take-off performance. The five constants relate to static thrust, a linear relationship between thrust and velocity, a non-linear relationship between thrust and velocity, air drag and rolling drag, and these five constants constitute at least part of the historical data.

Abstract: Apparatus for guiding an aircraft along the center line of a runway at rollout touchdown. A rollout predict path command is generated in accordance with a first path segmentY.sub.1 =T.sub.1 (Y.sub.m +Y.sub.u)(1-e.sup.-t /Ti)-Y.sub.m t+Y.sub.ion engaging rollout mode, which path segment transitions to a second path segmentY.sub.2 =Y.sub.1 e.sup.- (t-to/T.sub.1)at a given elapsed time t.sub.o, where T.sub.1 is a predetermined time constant, Y.sub.i is an initial value of lateral displacement on rollout engagement, Y.sub.i is the time derivatives threeof, Y.sub.M is a predetermined maximum lateral displacement rate, and t is the elapsed time. The predict path command signal is combined with a rate signal derived from a localizer position estimate to produce an error signal for commanding a rudder deflection to align the aircraft with the center line of the runway.

Abstract: This invention provides a flare control modification for pilot-in-the-loop aircraft maneuver command electronic flight control systems. During flare pilot pitch control inputs are interpreted as incremental flight path angle commands above a reference flight path angle (nominally a -3.degree. glideslope). The flare control modification allows conventional piloting technique (i.e., pitch controller pull-and-hold) to be used during flare, while retaining the benefits of the maneuver command system masking effects of gusts, winds, windshear, and variations in airplane weight, balance, and aerodynamic configuration.

Abstract: Energy compensation means (64) for an onboard aircraft flight management system (12). The energy compensation means may be used to eliminate unwanted throttle activity during unscheduled level segments (80) in a descent path. The flight management system includes means for enabling selection of various flight modes including a descent mode, means for determining a descent path, including target speed and target altitude (70) profiles as a function of aircraft position, and means for providing information regarding the aircraft current altitude, current position, current calibrated airspeed (CAS) and current true airspeed (TAS). The flight management system also includes means operative in descent mode for providing a target signal (V.sub.TGT) representing the target speed for the descent path for the current aircraft position, and display means (16) responsive to the target signal for displaying the target speed.

Abstract: An improved system and technique is disclosed which enables an aircraft control system to bring an aircraft to hover with no direct measurement of ground speed. The system includes a device for numerically calculating a value for ground speed based on a differentiation of aircraft position as measured from conventional ground reference navigational aids. The computed value of ground speed is compared with values representing heading and true air speed to generate a computed value of wind. The computed value of wind is then resolved into vector components of headwind and crosswind and the headwind component and air speed are summed to provide a signal used to control aircraft speed until zero ground speed is achieved.

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: A warning device, for a helicopter with a tail rotor and a mechanical protection device therefor, for giving during emergency power-loss landings a flare signal to the pilot to initiate flare followed by a tail/ground contact warning signal when the helicopter tail approaches too closely the ground. The warning device comprises in one embodiment a height-finder with two switchable transmitting/receiving antennas mounted at the helicopter tail to produce respectively, when switched into use, a height-finding beam backwards and obliquely downwards or forwards and obliquely downwards. Height signals obtained initially using antenna 40 are processed by computing means and initiate at a predetermined initial flare altitude a flare warning signal whereafter height signals from antenna 26 are used to determine the sink rate of the tail and in dependence upon this sink rate and the instantaneous height, a warning signal is initiated if this corresponds to a predetermined relative relationship.

Abstract: A glide slope indicator system in which light from an incoming aircraft's landing light is shaped by spherical/cylindrical lens combination into a line image which strikes a linear photodiode array. By determining which photodiode in the array the center of the line image strikes, the glide slope angle can be determined. An appropriate signal is communicated to the pilot via a pair of indicator lights mounted on the runway depending upon whether the aircraft is above, below or on the desired glide slope angle.

Abstract: Aircraft roll command signals are generated as a function of the Microwave Landing System based azimuth, groundtrack, groundspeed and azimuth rate or range distance input parameters. On initial approach, roll command signals are inhibited until a minimum roll command requirement is met. As the aircraft approaches the centerline of the runway, the system reverts to a linear track control.

Abstract: A control system for maintaining an aircraft within the lateral boundaries of a runway during landing rollout under conditions of combined crosswind and low runway friction is disclosed. An automatic mode of operation is provided wherein the system utilizes an input signal representative of the heading of the runway being utilized and signals provided by (or derivable from ) an inertial navigation system to exercise coordinated control of the aircraft rudder, steering and differential braking system. In a semiautomatic mode of operation, signals supplied by the inertial navigation system (or its equipment) are utilized in conjunction with a continuous command signal that is provided by the pilot to indicate the desired aircraft trajectory. An optional provision is included for limiting the aircraft ground velocity slip angle to a range wherein an increase in ground velocity slip angle results in increased lateral corrective force on the aircraft.

Abstract: A method and apparatus for determining the time remaining for maximum control action to be taken in order to achieve a desired objective (i.e., the chronodrasic interval) is disclosed. The method and apparatus continuously determines the amount of a parameter (e.g., runway distance) required to achieve a desired objective (e.g., stopping an aircraft before reaching the end of a runway on landing or accelerating an aircraft so that it reaches rotation speed before reaching the end of a runway on takeoff) if maximum control action is applied. The method and apparatus also continuously determines the total amount of the parameter remaining. The chronodrasic interval is then determined by deducting the amount of the parameter required to achieve the desired objective if maximum control action is taken from the total amount of the parameter remaining; and, dividing the result by a preselected (e.g., present or maximum) rate of change of the parameter.

Abstract: An improved inner loop control is disclosed for use in an aircraft pitch axis control system. Signals representative of vertical acceleration and pitch rate are complementary filtered and summed to produce an "inner loop" damping signal which is combined with "outer loop" command signals to produce an elevator control signal. The improved approach provides higher outer loop control law gains and better system stability, resulting in higher control bandwidth and tighter command tracking, especially in turbulence.

Abstract: A control system directs an aircraft along a predetermined curvilinear descent path (10). The aircraft carries a plurality of sensors, for example, an altitude sensor. The system has a longitudinal device (64) responsive to at least one of these sensors for providing a longitudinal signal related to longitudinal displacement of the aircraft. The system also has a height device (26) responsive to the longitudinal signal for producing a height signal functionally related to the altitude required to follow the path. Also, a command subsystem (36) responds to the height signal and a given one of the sensors to produce an error signal bearing a predetermined relation to the extent of deviation from the descent path. In one embodiment dispersion otherwise occurring during a flare maneuver is reduced by definitely directing the aircraft onto a specific path such as a circular arc. Such a control system may employ an aircraft motion monitoring system (FIG.

Abstract: The invention concerns a process for the rapid detection of a wind gradie t.This process utilizes the relationship existing between the aerodynamic slope .gamma.a, the total slope .gamma..sub.T and the anemometric speed V, relation being able to be in the form ##EQU1## in which s is the Laplace operator, A is a value which is substantially constant or zero, in the case of a normal flight without disturbances, and which increases in the case of a wind gradient, wind forward becoming wind behind, the Vsel is an assigned value. This value A is mixed with a value representative of the capacity of the aircraft to overcome a wind gradient, so as to obtain a composite signal compared to a value of reference.The invention can be utilized at the moment of the phase of approach of an aircraft.

Abstract: The aircraft is provided with an infrared sensor which is adjustable by means of feedback control so that its line of sight (image center) is and remains in line with the middle one of three infrared fires at and near the end of the runway. The craft is now maneuvered in such a way that its longitudinal axis is aligned with the horizontal component of the line of sight. After a particular distance has been reached, the aircraft descends while the image of the middle fire remains centered. The system uses existing equipment and is further supplemented to correct an initial gross deviation from the desired approach path.

Abstract: Upon aircraft landing approach, flare path command signals of altitude, vertical velocity and vertical acceleration are generated as functions of aircraft position and velocity with respect to the ground. The command signals are compared with corresponding actual values to generate error signals which are used to control the flight path.

Abstract: Aircraft altitude, ground velocity, and altitude rate signals are input to a computer which, using a unique control law, generates a pitch control surface command signal suitable for guiding an aircraft on its flare path to a specified runway touchdown point despite varying wind conditions.

Abstract: The present invention deals with a flight control process and device for an aircraft approach and landing. More in particular, the invention in use simulates ILS by using an infrared radiation source at the desired landing site. The invention comprises the steps of determining an axis defined by the infrared radiation source, forming a predetermined guide slope line with respect to the horizontal and oriented according to a determined approach magnetic heading, recording the aircraft position with respect to the source, determining the angular deviations in azimuth and in elevation of the sighting axis with respect to the said glide slope line, and operating the aircraft flight controls to return said deviations to zero.

Abstract: Upon landing approach to a runway, glideslope and altitude information is processed to produce an indication of ground distance to the touchdown point. Actual aircraft position is then determined by integrating the aircraft's ground speed. A display of distance from the beginning and end of the runway is provided. An alert is produced if the aircraft approaches the end of the runway at excessive speed. Further, the system may be coupled to the aircraft's autobrake system to automatically control the rate of deceleration.

Abstract: A control system for automatically activating the flight control surfaces of a STOL aircraft that utilizes upper surface blown flaps when the aircraft executes a STOL landing or takeoff maneuver with one engine inoperative in that the engine does not provide the desired or scheduled amount of thrust. The system monitors internal engine pressure of each engine to detect such engine failure and deploys the upper surface blown flaps, conventional flaps and spoilers used as direct lift control devices to provide a relatively uniform lift distribution across the aircraft wing and hence lower induced drag. When the aircraft executes a STOL takeoff procedure with an engine, that does not provide the proper thrust level the upper surface blown flap located aft of that engine is automatically extended to a position that matches the position of those conventional flaps located outboard of the inoperative engine.

Abstract: The inventive system requires that normal approach indicated airspeed and a predetermined approach groundspeed be used as the approach criteria, whichever is the least, compared to its own predetermined index value. These two values are the commanding functions fed to a fast/slow indicator and to any auto-throttle device on the approach, along with a "caution tailwind" warning device to warn the pilot whenever the groundspeed exceeds true airspeed by 5 knots or more, for example. If this warning activates, he should consider cancelling the approach and choose an approach from a different direction, determined by surface wind and his drift at the time of cancellation. This condition is caused by a tailwind component at altitude, the value of which the pilot can determine from his airspeed and groundspeed indications.

Abstract: Aircraft flaps provide rearwardly convergent channels which terminate at or near the trailing edges of the flaps. The forward intakes of the channels are closed when the flaps are elevated and open when the flaps are depressed. A control is programmed to operate the flaps so as to maintain minimum drag until sufficient ground speed is attained for take-off, and to limit the velocity of air discharged from the channels to sub-sonic speeds.

Abstract: This invention relates to a process for preventing undesired contact with land or water by low-flying aircraft which are assigned a minimum altitude and which are provided with instruments for measuring altitude, airspeed, angle of path, and transverse acceleration,Comprising measuring the rate of descent (H),transverse acceleration (b.sub.Q), when gravitational acceleration is eliminated,And altitude (H) to thereby ascertain whether the aircraft is above a given limiting altitude (H.sub.limit) determined from its ability for transverse acceleration and its flight data,And correcting the aircraft by the maximum feasible transverse acceleration (b.sub.Q max) when for a given measured value of altitude (H), the altitude is below the limiting altitude (H.sub.limit).

Abstract: A take-off and landing control device for automatic retraction of flaps upon stowing landing gear and upon attaining a predetermined airspeed and of indicating distance from brake release during take-off, and for an automatic decelerating approach with flaps extending as a function of distance from touchdown with automatic throttle cutback and automatic stabilizer trim in response to flap location maintaining an essentially constant angle of attack.

Abstract: In the vertical path control of an area navigation system when the aircraft ascends or descends to a waypoint with an "at-or-above" or "at-or-below" altitude requirement, vertical steering is effected at a constant airspeed with regard to a reference airspeed. An alert device is included to provide a warning to the pilot when the aircraft flight path angle is less than the straight line flight path angle to the waypoint for "at-or-above" waypoints or when the flight path angle of the aircraft is greater than the straight line flight path angle to the waypoint for waypoints with an "at-or-below" altitude requirement. Altitude error is displayed on a vertical deviation indicator of an aircraft flight instrument in accordance with the difference between the actual aircraft altitude and the altitude of the next waypoint having a firm altitude requirement.

Abstract: In a DME system, the least significant decade of the present aircraft to ground station distance is maintained encoded in a memory, and an up-down counter maintains a variable count. The complement of the present distance is compared with the present count, and when a difference is detected, a logical pulse increments the counter and also indicates passage of the aircraft through another distance interval. The sense of the difference between the present distance and the count also is monitored, responsive to which the direction of the count is controlled.

Abstract: In an aircraft terrain warning system utilizing a radar altimeter wherein the rate of closure to the terrain is compared with the aircraft's altitude above the terrain to generate a warning signal when the closure rate is excessive for a particular altitude, the closure rate signal is limited and biased depending upon the aircraft's closure rate and configuration in order to significantly increase the time response of the system while at the same time reducing nuisance warnings. The amplitude limit on the closure rate signal is varied, above a predefined altitude, as a function of the closure rate signal in order to provide increased warning times at greater closure rates. Circuitry, responsive to the aircraft's flap positions, is also provided to alter the characteristics of rate limiter so as to provide warning parameters that more accurately reflect operating conditions at lower aircraft speeds.