PAPIs
There are some good replies here. Below your DA/MDA the approach should be visual using the correct RoD and visual aspect of the runway, not using the PAPIs.
Because of the way the PAPIs are set up a pilot who flies the PAPI to touch down will end up with a flat long approach from DA with power on to hold the speed. All of which will make for a long landing with too much power.
It is perfectly normal and correct for smaller commuter aircraft to be in 3 reds and one white below DA/MDA on a correct visual approach. It can be seen from the helpful diagram posted above that it is perfectly safe and clear of obstacles. There used to be very helpful diagrams in an older version of the UK CAP168 which are unfortunately not there in the current edition.
Some charts publish LDA for a particular runway and with very good reason also state a reduced LDA if landing beyond the PAPI.
In short I agree with the advice above.