ADE English Manual 1.65 :
In ADE, you can select one of thirteen different VASI/PAPI configurations:
1. VASI (21, 31, 22, 32, 23, 33) – Visual approach slope indicators (VASI) installations
may consist of either 2, 4, 6, 12, or 16 light units arranged in bars referred to as near,
middle, and far bars. Most VASI installations consist of 2 bars, near and far, and may
consist of 2, 4, or 12 light units. Some VASIs consist of three bars, near, middle, and far,
which provide an additional visual glide path to accommodate high cockpit aircraft. This
installation may consist of either 6 or 16 light units. VASI installations consisting of 2, 4,
or 6 light units are located on one side of the runway, usually the left. Where the
installation consists of 12 or 16 light units, the units are located on both sides of the
runway.
In ADE, the first number of the VASI system (21, 31, 22, etc.) refers to the number of
bars in the lighting system. The second number of the VASI system (21, 31, 22, etc.)
refers to the number of lights per bar.
The VASI 33 system is different in that it has three
bars but only two lights on the far bar. You would use this system on both sides of the
runway to create a 16-light VASI.
Version AFLT 4516(a):
https://abload.de/img/vasi33jvkqf.jpg
Vasi are displaced a full row...