Quote:
VASI lights were never intended to be, and are not an acceptable source of glide path indication all the way to touchdown.
Can you provide supporting documentation? I've not seen this explained quite like that.
The VASI is not an acceptable guide, while the PAPI is. Not sure why anyone uses VASI any more.
The VASI gives a different touchdown point, depending if you are high or low on glide. The PAPI will always endevour to bring you to the same point on the runway, no matter how high or low you are.