Abstract: The outputs of a pair of linear accelerometers are utilized to provide measures of craft vertical acceleration and body axis pitch angular acceleration. The pitch angular acceleration signal is integrated to provide a measure of body axis pitch rate. The pitch rate signal is in turn integrated to provide a measure of body axis pitch attitude. An earth referenced pitch attitude sensor provides a measure of earth referenced pitch attitude and through a rate taker a measure of earth referenced pitch rate. The earth referenced sensor is utilized to calibrate out errors and effectively align the linear accelerometers so that in the event of a loss of the earth referenced sensor, the calibrated accelerometers have adequate accuracy to compute pitch rate and pitch attitude within the long period bandwidth needed to provide the stability augmentation function for a relaxed static stability aircraft.

Abstract: An air traffic control transponder includes a synchronous digital delay line decoder for providing mode selection signals in response to pulse space coded transmissions from the ground station. The decoder comprises a shift register delay line having a plurality of delay taps along which a first received pulse is shifted. A continuously running high frequency clock pulse generator via a frequency divider provides the shifting clock to the delay line. The first received pulse synchronizes the shifting clock via the frequency divider. A plurality of monostable multivibrators connected to selected taps of the delay line provide pulse detection windows in response to the first received pulse being shifted through the stages of the shift register to which the window generating monostable multivibrators are connected. The outputs from the window generators are applied as inputs to respective pulse coincidence detection devices, the second inputs thereof being connected to receive the incoming pulses.

Abstract: The dual electromechanical servo actuator comprises two electric servo motors coupled through differential gearing to position an output member in accordance with an input signal. Tachometer generators coupled to the respective output shafts of the servo motors, (and normally integral with the motors) provide rate feedback signals to the respective inputs of the servo amplifiers driving the respective motors. An electronic model of the dual servo actuators responsive to the input signal provides a rate signal simulating the tachometer responses to the input signal. A monitor compares the two tachometer signals and provides a failure signal when the difference therebetween exceeds a predetermined threshold. The monitor also simultaneously compares the model rate ouptut with the individual tachometer signals to determine which of the two servo channels has failed. The monitor circuits apply a brake to the servo motor output shaft of the failed channel.

Abstract: Apparatus for providing an integrated display of flight instrument parameters on the screen of a single cathode ray tube is presented. The synthetically generated symbology is equivalent to that typically provided by ten conventional electromechanical instruments including an attitude-director indicator, horizontal situation indicator, pressure altimeter, radio altimeter, vertical speed indicator, radio magnetic indicator, Mach airspeed indicator, autopilot-flight director mode annunciator, load factor indicator and true air-speed indicator.

Abstract: Apparatus for calibrating the magnetic azimuth detector of a gyromagnetic compass system utilizes the system gyro to provide a plurality of heading references to which the corresponding heading outputs of the magnetic azimuth detector are compared to provide cardinal and inter-cardinal error data from which one cycle and two cycle compensation coefficients are derived. The gyro heading references are compensated for gyro drift in accordance with the proportionate drift occurring with respect to a particular heading reference with respect to the total gyro drift occurring during the calibration procedure in accordance with coincident initial and final heading reference points. The calibration is effected by orienting the aircraft in which the gyromagnetic compass system is installed at the plurality of headings to provide the gyro reference and magnetic azimuth detector data.

Abstract: A dual channel, fail-operative automatic flight control system is disclosed in which each channel includes a totally monitored digital computer for operating upon sensor input data to provide command signals to the aircraft surface control actuators. The operative program for each computer is repetitively executed to effectively provide continuous control. The program is organized into a plurality of tasks to be performed by the computer with program segments associated with the respective tasks and a program routine for determining that all of the tasks have been completed for each program iteration. If non-completion of a task is detected, the program enters a failure routine which stops execution of the program. The program also includes a routine for generating a dynamically varying pattern in accordance with the continuously reiterated execution of the program.

Abstract: The digital stroke display generates vectors by applying clock pulses to an up/down counter which through a digital-to-analog converter provides the deflection voltage for one of the display X or Y axes. The clock pulses are applied through a gate to a second up/down counter which through a second digital-to-analog converter provides the deflection voltage for the other of the X and Y axes. The gate is controlled by the overflow of an accumulator that is repetitively accumulating, under control of the clock pulses, a signal representative of the desired slope of the vector. Circular curves are generated by a concatanated series of vectors utilizing the vector generation apparatus where the signal representative of the vector slope is provided from a memory that stores the plurality of slopes for the concatanated vectors that comprise the circular curve.

Abstract: Aircraft weight and balance computer apparatus processes sensor outputs to generate an electrical signal that is proportional to aircraft gross weight at the time take-off thrust is initially applied to the aircraft on the runway and continually updates the weight signal when airborne to account for burn off of fuel or other weight loss and also provides a measure of the location of the aircraft center of gravity position. This is achieved by computing the aerodynamic forces on the aircraft in its longitudinal plane and the thrust generated by the engines and relating these computations to the corresponding acceleration components measured by a pair of linear accelerometers that are mounted orthogonally in this longitudinal plane.

Abstract: A flight control system utilizing a limited authority stability augmentation system having a long term attitude and/or path control input to enhance the automatic flight capability of the stability augmentation system. A position sensor coupled with the limited authority stability augmentation actuator provides an indication to the human pilot via a suitable indicator when the actuator is near or at the limit of its authority thereby permitting the human pilot to effect manual trim, thus recentering the actuator.

Abstract: The one's complement subtractive arithmetic unit comprises a parallel adder with a connection for providing an end-around carry, from the carry output of the most significant stage to the carry input of the least significant stage. The parallel adder is implemented utilizing multiple bit LSI ALU chips or microprocessor slices that provide group propagate and generate indication signals. Carry look-ahead chips responsive to the group propagate and generate indication signals provide a fast carry arrangement for the arithmetic unit. Circuitry is included to detect when all of the carry propagate indicators are on for providing a signal to the carry input of the parallel adder resulting in the equivalent performance of a one's complement subtractive arithmetic unit.

Abstract: A yaw axis stability and command augmentation system (SCAS) particularly applicable to STOL type aircraft includes three primary control terms proportional to side slip angle, side slip angle rate and rudder pedal force, wherein side slip angle rate is synthesized from measures of yaw rate, bank angle and lateral acceleration. These primary system feedback terms are supplied to the rudder electro-hydraulic secondary actuator which is positioned in accordance with their sum. The system serves to provide improved automatic damping of the Dutch roll modes, to suppress aircraft motion transients in yaw and roll under engine failure situations, to provide automatic turn-coordination in maneuvering flight, and to provide a side slip angle command capability to improve manual control precision in approach and landing under crosswind and lateral wind shear conditions.

Abstract: The decoder buffer is utilized in a memory system for an array of variable threshold MNOS transistor memory cells arranged in word rows. The gate electrodes of the memory transistors comprising each word row is coupled via a word line to the output of a decoder buffer. Inputs to the decoder buffers are provided from address decoder and inverter circuits in response to memory address inputs. FET control circuitry is included for selectively providing operating voltages to the decoder buffers in accordance with the various memory functions performed. Each decoder buffer comprises first, second and third fixed threshold field effect transistors, the first and second transistors being serially connected with respect to each other, forming a junction therebetween which is coupled to the associated one of the memory word lines.

Abstract: A multiple function generator is described in the environment of an airspeed indicator for controlling the maximum allowable airspeed needle in accordance with a plurality of selectable functions of altitude and comprises a cam having a plurality of surface segments shaped in accordance with the functions positioning a cam follower coupled to the maximum allowable airspeed needle. A null-seeking electro-mechanical feedback servo mechanism having an altitude signal applied to its input synchro drives the cam, thereby positioning the needle in accordance with the function of altitude represented by the cam surface segment in contact with the follower. Means are included for altering the null index of the servo thereby selectively engaging the desired cam functionsurface segment with the cam follower in accordance with the function desired. A selection knob is coupled with the indexing means for selecting the function.

Abstract: The display generator comprises a map memory having a plurality of addressable locations corresponding respectively to a plurality of incremental display cell areas of the display screen. The apparatus further includes a symbol memory having a plurality of storage matrices for storing the respective plurality of patterns and symbols to be selectively written into the incremental display area cells to thereby form a display picture. The display raster is generated by digital circuits which sequentially address the map memory locations. The map memory words stored in the respective locations each includes a symbol memory address. The digital raster generation circuits are also coupled to the symbol memory for addressing the line of the symbol selected by the map memory for the line by line writing of the selected symbols in the cells of the display.

Abstract: A magnetic head switching matrix selectively couples a plurality of balanced read-write heads to the output of a write amplifier and to the input of a read amplifier. Constant current supplies apply equal constant currents to a pair of write data lines connected to the write amplifier output and two further constant current supplies apply equal constant currents to two read data lines connected to the read amplifier input. The two coils of each head are coupled to the write data lines through two matched diodes respectively and are similarly coupled to the read data lines through another pair of matched diodes respectively. The center tap of each head is coupled to write and read reference voltage sources through respective diodes as well as being coupled to a read-write control voltage source.

Abstract: The circuit derives a rate signal from an a.c. signal proportional to attitude displacement provided, for example, from the synchro pickoff of a vertical gyroscope or an inertial navigation system, the pickoff receiving power from the aircraft a.c. power supply. The a.c. attitude signal is passed through a first bandpass filter tuned to the frequency of the power supply. The a.c. power supply signal is passed through a second bandpass filter identical to the first whose output is used as the reference signal for first and second identical demodulation circuits which include first and second matched low pass filters respectively. The filtered a.c. attitude signal is applied to the first demodulator circuit and the filtered power supply signal is applied to the second. The output of the first demodulator circuit is applied to a line voltage compensator and the output from the second demodulator circuit is applied to a d.c.

Abstract: A digital memory comprising a plurality of contiguous circulating serial data storage loops and a plurality of processing elements. Each pair of adjacent loops are coupled to a processing element such that each loop is coupled through two processing elements displaced by one-half loop length. Each processing element includes a serial comparator and a loop control circuit for either isolating or exchanging the data on the two incident loops. Additional circuits are included in each processing element which in combination with the comparator and loop control provide the memory, as the loop data circulates through the processing elements, with the capability of performing an ascending or descending sort of its contents, an associative search of its contents with retrieval of located data, an updating of stored data records, a loading or unloading of a record file or data base and a dynamic reconfiguration of the memory structure.

Abstract: Two substantially identical servo channels, coupled through a differential mechanism, position an attitude control surface of an aircraft in response to a common command signal applied to both channels. The common command is coupled to each channel through separate displacement and rate limiting devices to limit the attitude displacement and rate of change of attitude commands about the associated aircraft axis. In the pitch axis a separate normal accelerometer controls each command rate limit so as to prevent excessive pitch maneuvers due to the common command source.

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: Control apparatus for an aircraft area navigation system provides a vertical path control signal to cause the aircraft to ascend or descend along a helical surface as the craft executes a transition laterally from the inbound course to the outbound course of a waypoint whereby the craft attains the waypoint altitude when crossing the course bisector thereof while maintaining a predetermined vertical flight path angle when steered on a predetermined lateral course transition path.