Approach On Papi

[PEI_3721]

The basic location of PAPI provides approximately 50ft threshold crossing height (wheel height); this depends on aircraft type. For those aircraft with larger than average wheel to eye height a second set of PAPIs may be provided for a particular runway (located further down the runway)
I recall the Airbus statement re A340, but do not have the reference to hand. From memory the wording was such that when approaching an airport without a second set of ‘long body’ PAPIs, then the standard PAPIs should be ignored at low altitude.


BOAC

In any case PAPIs should always be 'ignored' below 200' when you should be aiming at a favourite spot on terra firma.

Are you getting mixed up with the old VASIS which were unreliable below 200ft - red/white=pink?
PAPIs are precision devices which project a very accurate beam (sharp transition) between red and white. For most aircraft they are usable to the lowest altitude that you wish, although a visual landing requires the appropriate concentration on the runway as altitude reduces. It may also be impracticable to see the PAPI as they move to the edge of the visual scan, but they might provide a peripheral cue of wind-shear or landing short.