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Display in the cockpit

PPI-Display

Figure 1: Display in the cockpit

Höhenwinkel [degrees]
Höhe [ft * 1000]
Entfernung [NM]

Figure 2: Calculation of a Vol-CAPPI-Display

elevation [degrees]
Height [ft * 1000]
range [NM]

Figure 2: Calculation of a Vol-CAPPI-Display

Display in the cockpit

The PPI - display present a „map style” view of the oncoming weather. It is common to have powerful controls to allow the pilot to zoom in and out of the viewing display screen as he requires.

CAPPI: (Constant Altitude PPI)
is a horizontal, two-dimensional representation of radar measurands in a certain height (or Altitude). A CAPPI is calculated from several PPI measurings at different elevations. The different heights are usually represented by color variations on a PPI-Scope.

Vol-CAPPI-Display
Click to enlarge: 640·480px = 67 kByte
Figure 3: Structure of a Vol-CAPPI display

Vol-CAPPI: (Volume Constant Altitude Plan Position Indicator)
A further representation is called Vol-CAPPI and allows a clear echo assignment in all three cracks. In addition to a floor plan, an outline (corresponds to a side view from east to west) and a cross view (corresponds to a side view from north to south) are also shown. With the help of a cross-hair cursor the positions of these sections can be selected arbitrarily.

In aMAX (imum)-CAPPI the maxima of the CAPPI data from different heights are displayed. This is done on the one hand by a vertical maximum projection in an (image) elevation, on the other hand by horizontal maximum projections from south to north or from west to east in side elevations. In the side views the lateral scale indicates the height in km. In a MAX-CAPPI, reflectivities are mostly displayed.

A so-called pseudo-CAPPI (pCAPPI) differs from a CAPPI in that additional values are extrapolated in the far zone.