Horizontal Situation Indicator

The horizontal situation indicator, HSI is an instrument for radio navigation of aircraft. And the flight path, it serves primarily as a backup for other, more modern navigation systems, such as, for example, the HSD ( horizontal display position ) is used.

Tasks of the instrument

It is a combination instrument VOR receiver, gyro compass ( Gyrosyn ) and Glide path for the instrument landing system ILS, united the various navigation information in a device, thereby facilitating the funknavigatorische work in the cockpit felt. Compared to separate instruments, the representation of the HSI provides a faster and more intuitive overview of the spatial relationships and allows the precise execution of complex instrument flight procedures, such as of holding procedure and instrument landing approaches.

The HSI is particularly used in aircraft which are frequently flown under instrument flight rules. Some aviation GPS receivers also have an HSI display, but it is limited compared to fixed built- in aircraft systems.

Construction

The device is connected to the gyro compass, the VOR receiver, the Glide Slope and the autopilot. The glide slope indicator appears on one or both sides as a small yellow triangle.

In contrast to normal VOR display the HSI has a degree wheel, which is tracked as a gyrocompass, which therefore rotates with the variable rate. On the HSI its own plane in the center of the instrument is ready to be miniaturized. VOR or ILS localizer is presented in relation to the miniature airplane.

Interpretation of display

The HSI provides guidance bird's-eye view for navigation. There is the course, heading and bearing information relative to a VOR, to control points on runways, or marker points.

In a normal VOR indicator RIGHT and LEFT and TO / FROM should be interpreted with respect to the set course. If the HSI is set to a VOR station, right and left and real right and left. TO / FROM is simply represented by pointer. The own position (aircraft) is in the middle. If the arrow points upward ( front), is (TO) meant the arrow points to the rear ( below) is meant FROM.