Thanks folks. I do have one more thing to add regarding the HUD - without wishing to derail this thread - I didn't mention this in my previous post because I was responding to the specific suggestion of somatogravic illusion.
The HUD exaggerates everything, compared to the traditional PFD, due to it's far greater size in the pilot's field of view, and therefore appears to be far more sensitive. This is why a HUD user can fly far more accurately.
However, this can "appear" to work against you in situations of moderate to severe turbulence. I say "appear" to work against you, but does it really?
For example, many years ago while I was learning the HUD in the simulator, we had to practice a severe approach windshear encounter using the HUD.
On the 737, the windshear escape manoeuvre, (after performing initial actions such as maximum thrust, 15deg pitch) recommends following F/D guidance - because the F/D has a "windshear mode" which gives very useful guidance. On the HUD, the F/D (or guidance cue as it is known in the HUD world) appears to dash all over the screen - as it responds immediately to every turbulent aircraft pitch and yaw - to the point where attempting to follow it appears to become an exercise in futility.
I said as much to the instructor after the event, having concluded already that I basically had no control over the aircraft using the HUD. He then asked the F/O what he thought of my efforts. The response was "extremely well handled". According to his PFD, I was flying the F/D very accurately, and the whole manoeuvre was very well flown.
The moral of this story is that using the HUD in severe turbulence or windshear might make you think you are flying badly, but in fact you are not. Your negative self-assessment is just due to the sensitivity of the instrument. Understanding this is critical to HUD proficiency.
Having said that, any experienced HUD pilot will know this, because they will have used the HUD during a many a turbulent approach to land, and learned not to over-control accordingly. They will also know that if they are not liking the HUD then they will automatically go eyes-to-the-PFD.
The aircraft involved in this accident was probably experiencing turbulence and maybe windshear. However, I personally can't conceive that HUD over-controlling was in any way a contributing factor to this accident. All the same, I just thought I'd end my HUD explanation with an honest and unbiased appraisal of the pros and cons of the instrument, and to point out again that training and experience is necessary to use a HUD.
Last edited by Derfred; 4th May 2016 at 16:13.