For the U.S., the numbers are documented in the AIM to give the angles etc for both 2-bar and 3-bar VASI and normal PAPI systems. Generalizing:
A 2 bar VASI is simply a 3 bar VASI with one of the bars missing so I recommend doing 3 bar units consistently everywhere. The PAPI unit has all the lights at the same location, only the angle for the color change is different. Therefore, aircraft that need a greater threshold crossing height for the pilot viewpoint are forced to use a steeper approach angle which is inconvenient for them. In contrast, the VASI has small aircraft use the two nearer bars while larger aircraft use the two further bars. This provides both a steeper angle for large aircraft as well as additional distance down the runway which in combination provide the needed threshold crossing height. As a result, the descent angle for wide bodies is less steep. > Yes, there are definitely complications, but right now our data has > N=none, V=vasi, P=papi, so I'm planning to start simple. _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
