Eye Height
Capt Bloggs. You are correct, the eye height at threshold is the same for small and heavies but wheel distance to touch down not. The papis give a theoretical touchdown point without taking into account(not possible) the flare. I can tell from experience that to land a barbie jet as with T/P s at 300 m requires the pilot to try and land 150m before the fixed distance markings,I.e start dipping into 3 reds into the flare. Conversely a B747 requires the pilot to try and land at 450 m as stated in "Handling the big Jets". The papis are more suited to medium sized jets B737/A320 and should allow the pilot to aim at 300m and actually touchdown there.