You won't see the threshold in 800m. It's unlikely you'll see the first crossbar as it's going to be under the nose of whatever aircraft you're flying so that will leave you with the remaining 4 crossbars, and you may not quite see the 4th, closest to the runway, in 800m vis.
And thats basically what I've been on about.
Mentioned previously which I agreed with- "what you expect to see when visual".
If you are expecting to see what you describe above, and that's what you see, then you are ok.
But what happens if its blatantly obvious that you cannot see past only 1 or 2 bars? (You've 'counted' those bars havn't you?) Presumably one would deduce that they do not have the required vis and commence the missed approach.
Do any aircraft manuals state that you lose X metres of vis or that they hide a certain amount of approach lights under the nose for situations such as this?
The method of checking the crossbars is just one of the ways in assisting you in determining your visibility.
Don't know why I've copped so much flak about it. As seen in the "how to start a hot injected engine" thread there are many ways about going about things yet there doesn't appear to be any negativity such as this over there!
Forkair SOPs state that at the minima you must be able identify enough on the ground to fly the aeroplane to safe touch down - or else you bug out. Start of the HIAL (I thought that was the purpose of HIAL ??), lead-in lights, PAPI/VASIS, whatever.
I'm hoping that just because you see the start (and presumably not all) of the HIAL lights doesn't mean you think it's safe to continue.
Almost like saying "I can see a couple of edge lights, so i can take off" even though its actually below the takeoff minima.
The DA at Townsville puts the HIAL right in front of you - if I could see the start of that it would never have occurred to me that I might not be legal to land.
Herein lies my point with the amount of crossbars you can or cannot see!
If you only see 1 or 2 then thats not the required vis.
Its more recognition of what you are expected to and subsequently seeing that I'm on about, and recognising 3 or 4 rows of lights 150m apart is not difficult in a momentary half-second glance out the screen.
If you are looking out the window to identify something to to determine if you have the the required visibility (or not), be it the threshold lights PAPI/VASI or the 500/1000/1500ft markers, why is it inconcievable to some that the crossbar lights are also a valid way?
Direct, yes an interesting discussion and thanks for the input. The method I've mentioned might not be all that practical for you at your speeds, but I'm sure there are plenty of aircraft out there that can and do go slower, in which case they might find that the crossbar lights works for them.
I think the word "count" has brought about a bit of confusion to some, for which I apologise. But what other word can be used to describe recognising a numerical amount of things?