Originally Posted by dirtyrat
OP is quite right to ask in my opinion.
I can't answer your question with any wisdom but I can tell you that a hull loss occurred because of precisely this. In the picture below, look at the difference in wheel heights between the 2 bizjets for the same pilot eye heights.
My company operate jet charters to main intl airports as standard, but also occasionally to small airfields where PAPIs have been setup for smaller aircraft. The example below is always brought up during our recurrents.
Go easy on me please!
While the concept of superimposing the profile of 2 different aircraft positions and ensuring that the pilot-eye-point (i.e., cockpit window) of each is in essentially the same location can be very enlightening, I think this kind of presentation deserves just a couple of comments …
Of course, anyone should recognize that the position of the airplane is of paramount importance when approaching to land – it is also true that the relative positions of the various aircraft sections (i.e., nose, tail, fuselage, wings, wing tips, landing gear, etc.) are every bit as important. In the two aircraft positions presented in
dirtyrat’s post, it is fairly easy to see that the cockpit windows of each of the superimposed aircraft are in essentially the same location – fore-aft and up-down … I’m not at all sure if they are the same with respect to left-right, in that the aircraft in the “low” tail position, appears to be a lot closer to the camera lens than the aircraft in the “higher” tail position ... however ...
Everyone should be aware of what the correct landing attitude should be – that attitude is the “level flight attitude” for the existing weight and airplane configuration at the Vref airspeed. Clearly, the airplane in the “tail low” position is not in the proper attitude for landing – regardless of what the VASI or PAPI lights are indicating. That is the likely place to start a critique for the pilot who was at the controls of this particular airplane – either that pilot had some distraction or awareness difficulty that should have dictated a go around long before getting to this depicted point OR that pilot has no idea of what he/she is flying – and likely knows little, if anything, about landing an airplane.
Also, we should recognize that pilot eye height is a pilot seat position within the respective cockpit (again – fore-aft, up-down, and whatever left-right adjustment may be available) and it is to help ensure that adequate visual references will be available when getting to the point that the pilot will be flying with respect to strictly visual cues. Of course that will be heavily dependent on the pilot having the airplane itself in the proper attitude – otherwise, without being in the proper attitude, where ever the pilot’s eye is positioned in the cockpit will have little relevance to what is happening on the outside of the airplane. We have adjustable seats so that pilots are able to achieve the proper eye position, regardless of his/her own physiology, designated for that airplane. That means, a pilot should not only use the alignment indicators, but should also check the other references he/she is accustomed to using – vision over the control wheel or control wheel hub … visual capability (or lack thereof) down the top of the glare shield, the amount of windshield frame that is visible, the amount of airplane nose that is visible (if any), etc., etc. Even if the pilot of the airplane in the accompanying superimposed picture with the tail low had his/her own eye position “nailed” at the correct position within the cockpit – there is no way that pilot would be able to see the outside environment anywhere near what should have been visible. With such a nose high attitude it is very likely that the pilot would have had difficulty in being able to see the departure end of the runway … let alone the landing area of the runway on which he/she was preparing to land. Not being able to see where it is on the runway you are going to land should be a dead give-away (pun intended!) that something isn’t right. In this particular case, someone, should have recognized this developing scenario long before the airplane reached the position depicted in this photograph.
I wouldn't put too much credence in the fact that VASI or PAPI lights can miss-lead a pilot to the degree that he/she could correctly use those visual aids and still wind up in the position indicated by the aircraft with the tail low in this photo. This pilot obviously had other, rather distinct areas where his/her attention, recognition, and/or piloting response was severely lacking! Aviation is not everything in one basket - just like its not just airspeed or not just altitude or not just power setting ... there are a multitude of factors that all have to be taken into consideration - all have to be managed - and they all have to be monitored and corrected when, where, and HOW ... as it becomes necessary to do so.