Originally Posted by
172_driver
The amining point markers at Skiathos is about 150 m from the threshold. Runways with a length above 2400 m (is it?) has the aiming point markers at 450 m past the threshold. The threshold crossing heights can't be the same, if your objective is to land at the aiming point. The performance in-flight calculations for Actual Landing Distance from 50 ft doesn't care about the runway length.
I still take it a reasonable debate need to establish the geometry first, and then start factoring the human factors on top of that.
The aiming point markers are the same thing. If the painted in the wrong place, an AFM-like landing cannot be flown towards them. On a 3°/50' standard AFM or ILS profile the RA 'over numbers' height is 30 feet. The LDA and LDR + FLD + OLD + RLD should be satisfied with their inherent margins as applicable using that technique which should be the same no matter the landing distance (fact to me, but respecting the reality that HF will phase shift that in reality).
Should you choose to aim for the 150 marker the resulting gear clearance is
8 16 feet which is not much room for error but as this runway has the threshold displaced by around another 60 mtrs the wheel clearance over the property edge is assured by 25', pretty close to the normal standard.
[edit: but not really only 8, the flare will be most likely happening by then]
Other words: A pilot taking his 320 into a runway so short the aiming marker is unusable for his landing geometry should know not to use it. Was that covered in my short runway training - definitely not. If then, upon seeing the underrun and feeling comfortable (that has not bitten anyone ever, right), the instincts take over and he cuts it short into the first marker - then by all means that is how life works.
Similar but opposite direction, keping the ILS centered to about 100 feet RA and then flying the landing towards 400 mtrs aiming markers + PAPI at Palma / Manchester / Fumicino / Dubai is susceptible to building a habit of a 2 degree profile at 66 feet over threshold (RA 50).
Bring that style to JSI and there will be a massive 'does not compute' moment overloading the normal routines. The rest is videotaped above.
Saying short runways need to be landed short or the aim point markers (at varying distances) should be used to schedule the landing trajectory - sorry sir. I don't mind if you do and trust your skill to make it (repeatedly) but the standard of explainign to others or teaching need to be better than that.
Yet so far the key lesson was completely missed, save for one post.
Why the crew did not go around?! Not whether they should but why they did not. I think anyone here can learn a bit if we dissect that.