Originally Posted by tony montana
737fctm state:. The PAPI may be safely used with respect to threshold height, but may result in landing further down the runway
We need to keep this in perspective. The aim point difference from 50ft eye height (3°) to 70ft eye height is only 116m (289m vs 405m). I very much doubt if you would ever find a PAPI with a eye height of more than 50ft on a runway less than 2000m long; "Landing further down the runway" then, while technically true, is not going to mean you land with less than the distance
required.
Originally Posted by tony montana
if you go all the way down 2 whites 2 reds, you will land beyond aiming point most of the time. So the point you are targeting 120nm away, the point to where is ending your descent profile may be missed and all your landing calculations a bit useless.
I may be misreading this, but a 120m difference in your aiming point will have no practical effect on your descent planning. If you were implying planing for exit taxiways, your aerodrome chart will/should have the eye heights for each runway so you will know the aimpoint beforehand.
Originally Posted by A4
PAPI's can be set for different eye heights - a B747 isnt going to see the same as a Citation.
Yes they will. PAPI 2W/2R is a single path to a point on the runway. The eye heights from each cockpit will be exactly the same. The wheel heights won't be, but when crossing the threshold, if published eye height is 50ft, then that's the height of the 747's and Citation's eyes.