In an aircraft flight instrument display system having a display screen for displaying flight information, an airspeed indicator is displayed in a vertical tape format, and has a low speed range indicator with a low speed range identified on the airspeed indicator by highlighting the low speed range, and has at least a settable indicator within the low speed range indicating a critical airspeed. The low speed range indicator and the critical airspeed indicator are both set with only manual inputs.

An integrated flight control indicator for providing visual information indicative of aircraft flight parameters has a sky arc and an earth arc which are visually distinguishable from one another. The sky arc and the earth arc cooperate to generally define a circle wherein the relative lengths of the sky arc and the earth arc indicate the pitch of the aircraft. A horizon line extends approximately between the two intersections of the sky arc and the earth arc so as to provide a visual indication of the roll of the aircraft. Other indicia are provided for indicating radar or barometric altitude, vertical speed, heading, ground track, minimum altitude break, etc. Thus, the present invention provides a visual indication suitable for use in instrument panel displays, heads-up display, and helmet-mounted displays.

A synthetic rendering of the terrain within a selected field of view is created from raw terrain elevation data, and the resolution of the rendering is proportioned to the altitude above ground level (altitude AGL) of the aircraft. All the data points are subdivided into tiles. Only data from tiles within a prescribed field of view are considered for processing; all others are ignored. Within the selected tiles, only some of the terrain elevation data points are passed to the graphics processor for rendering. At maximum resolution, when the aircraft is on the ground or at a low altitude, there are relatively fewer tiles within the field of view and the fraction of the data points from each tile within the field of view passed for rendering is relatively large. As the aircraft's altitude AGL level increases, the field of view also increases in area increasing the number of tiles within the field of view. However, the number of data points forwarded for rendering by the graphics processor is kept approximately constant by selecting progressively fewer and fewer terrain elevation data points from each tile for rendering as altitude AGL increases. Only the data points that lie within tiles inside a prescribed field of view are forwarded to the graphics processor for rendering. Once the tiles have been selected, the terrain elevation data points are grouped in groups of a size that depends on altitude AGL, with more terrain data points in the grouped as attitude increases. Preferably the groups are triangle strips. Only the highest elevation from each group is passed to the graphics processor for rendering.