A moving altitude tape for a flight instrument display adapted to provide intuitive visual cues for determining deviation from a desired altitude. A window incorporates a digital altitude readout and a pointer index which is aligned with calibration marks on the altitude tape. In use the tape exhibits a motion in accordance with deviations in altitude of the aircraft and displays a vernier indication of such deviations with respect to the reference index. The tape further includes indicia associated with the reference index for defining predetermined increments of altitude deviation in accordance with commonly commanded altitudes, and a further pointer indicative of actual altitude deviation from a preset altitude.

Method and indicator for displaying information showing the airspeed tolerance margins for an aircraft.The indicator comprises a central processing unit which selects, from a plurality of longitudinal scales, the longitudinal scale representative of the current aerodynamic configuration of the aircraft and a display means which presents on a display screen the selected longitudinal scale, which is mobile in the longitudinal direction, and whose position on the display screen depends on the current angle of attack of the aircraft, shown by a characteristic marker in a fixed position on the display screen across the longitudinal scale, the latter scrolling up and down relative to the characteristic marker as a function of the current angle of attack of the aircraft.

A display device particularly suited for providing the pilot of an aircraft with combined inflight attitude, heading, altitude, and horizontal situation information previously available only by using two or three devices providing separate displays. The preferred embodiment of this invention combines a commonly used and commercially available flight director-type device for providing a display in combination with a miniature aircraft supported for angular displacement from a vertical orientation to indicate heading error, or heading offset, and an extended course deviation indicator bar which projects into juxtaposition with the miniature aircraft for providing a true picture of the aircraft's horizontal situation relative to a selected VOR, ILS, or MLS course.

A Heads-Up Display system which displays an attitude reference to pilots in order to provide a reference display system as a primary flight instrument. The Heads-up Display system uses a pitch ladder system based on Euler angle data which eliminates the erratic motion or "flip-flop" of the typical pitch ladder which is inherent and unavoidable when pitching near plus or minus 90.degree., by utilizing a flexible graphics display which presents the pilot with a heads-up view as if he were located inside and at the center of an imaginary sphere which has heading and pitch angle information marked on its inner surface. The display of appropriately curved bars as opposed to a straight bar pitch ladder for attitude reference more realistically depicts to the pilot the aircraft situation relative to the outside world. This presentation is more easily and more reliably interpreted by the pilot and simplifies the recognition and recovery from unusual attitudes. In addition, ground track, yaw rate, turn rate information is available over the entire HUD field-of-view, thus there is no need for the pilot to redirect his attention away from his primary point of interest, the velocity vector, to obtain heading and track information. Appropriate equations are evaluated to obtain line-of-sight angles from the aircraft longitudinal axis to the desired pitch and heading points on the pitch ladder display. Such equations are solved by computer techniques for a sufficient number of intersecting points to complete the display and the graphics hardware connects the points to form the segments of the pitch ladder which represent the imaginary lines on the sphere and displays the same in the pilot's field-of-view.

An artificial horizon display generator determines either sky shading or ground shading in real time as each pixel of a raster display is generated. Transition line parameters are specified by host processor, whereupon the display generator computes whether the raster line currently being generated will intersect the horizon boundary line, and if so, at what X-Y transition point. Pixels generated prior to the transition point are of the initial shading; pixels generated subsequent to the transition point are of the opposite shading.