This is exactly why I was trying to get some clarification because I will be flying the same approach probably next week, and I guess I’ll prioritise the PAPIS (it’s a long runway anyway) and be above the GS.

4 reds before touchdown on an autoland (at 1min 20sec):

the issue is the 4 reds were probably more around 150ft for me….the ltc in his comments wrote that I was strangely on GS when I got 4 reds. Which is the confusing part I guess, but also the reason he was happy for it to continue.

Then you'll get a flogging from the FDAP manager for being unstable above the GS! :D Life's tough, and then there's grumpy captains!!

The main measure of success or otherwise: if you touch down in the touchdown zone with no big pushes or pulls, job done.

Remember, the reason that the PAPI is not at the 300m point with the ILS GS antenna is because the runway is long enough for long-bodies. Landing distance should normally not be an issue even if you flew down the PAPIs instead of the GS.

Yes, I've noticed.

We had been discussing 4 reds being a geometric necessity
- where GS intercet pt. and PAPI have significant lateral shift (150m, more than a 100).
- below roughly 50 feet as the parallel 3 deg path slices through the PAPI segments downwards.

​​​​Whereas your airport has
- distance rom GS to PAPI only 70 meters
- you had 4 reds just below 200 feet, around 1 km to runway still.

That is a profile which needs retraining. Or it does not add up.

The piece where you say it was on GS and with 4 reds does not match the puzzle. On a CAT II instalation even less so.

This needs to happen and will when both of the conditions described above are satisified but neither was by your description.
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It's also his job not to give you contradictory instructions where you will necessarily fail at one or the other.

If I remember right they turn the papi off for CAT3 landings, maybe for this very reason

I don’t think anyone has mentioned the disparity you often get between GS angle and PAPI angle. Numerous airfields I fly to have PAPI set to 3 degrees when the GS angle is less than or greater than 3 degrees. You need to brief at what point you will disregard the FD and fly visually with reference to the PAPI, or brief what you will see when sticking to the ILS.

Surely you don't want to confuse the autoland.

haha.. confused me obviously.
I really can’t remember if they were turned off for CAT 2, we had the option of manual landing off them.
Probably don’t remember because never looked at them.
Do remember there was a few airfields that if you did fly the papi (accurately) you would set the glide slope warning off.
Yes that contradicts the never looked at them!
We were allowed to fly manually, even approaches, after a few ignored glide slope warnings doing this we were told if doing manual visual approaches press the g/s inhibit button.

CAT2, CAT3 PAPI possibly disconnected.

PAPI location is determined by the eye to wheel height of the largest aircraft regularly using the runway to give 50 ft threshold clearance.

And then they fly the GS for autoland leaving only 29. Oh yes.

​​​​​​Somebody link the VIS/RVR facility degradation table, so we can see the penalties for PAPI inop.

Except, is an aid not a facility.
To be used for the approach not landing.
During visual manouvering, not instrument flight.

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Where I am now 4 reds on PAPI is a mandatory GA below 1000 ft. If it is there use it, within its applicable scope.

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It may be an interesting academic discussion. But in my opinion we are doing ourselves (and the OP) a disservice if we pay this much focus to PAPIs and G/S indications at low altitude.

I have aimed at the zebra stripes on short slippery runways. I have aimed at half way down the runway at AMS where the exits are at the far end. Know your plane, know your surroundings.

Agreed with 172 Driver. For the last few hundreds feet assuming you are visual, outside reference is the primary reference. Below 200 feet, you should focus on the aim marker and not focus on the glide slope or Papi at this point. In fact you should disregard them at this point or you might end over controlling the aircraft.
Mentour explains it pretty well on this video after the 4min mark.

pineteam There you go, at #36.

thanks that’s a good video.

Nonsense. We're trying to get people into the same box over the threshold each time so there's less variables, not John Wayneing it. Landing half way down the strip so you can taxi off quicker will get you a free tea and bikkies pretty quickly. You ever heard of FOQA/FDAP/FDM?

Nobody's suggesting you concentrate wholly on the guidance below 200ft. But they (GS or PAPI) should be front of mind until 200ft. Re the "last few hundreds feet" is where it often all goes pear-shaped because of slack glidepath control.

That is an interesting video. His comment about being coordinated with the ILS is rarely valid these days. The PAPI is almost always further in, to suit long-bodies on longer runways. Also, I don't agree with his philosophy of use. The first thing you do is nail the PAPI, to the dot, stay on it then, at 200ft, start transitioning to the visual aim point by holding that spot steady in the windscreen. It is impossible, for a newby at least, to start assessing the aim point moving or not on the windscreen at 1000ft, as he is suggesting. Even I can't do it. The touchdown zone is so far away that any minor pitch movements throws this spot on the windscreen around chaotically. Only when you get in closer does "holding the aim point" become doable. I notice a commentor has a similar view to me.

For Pelican, a commentor also mentioned a PAPI that looked odd and which was later found to have been run over by a vehicle and bent out of shape. So you never know, the PAPIs at your airport might be skewiff, or the glideslope bent!

At night, impossible to see the markings and read the aiming point from them, sure pilots need to pick up the 'collision' point by obesrving the visual field expand.

About 500 is the first feeling I get for it, the centreline lamps become distinct one from another. The key is flying the GS / FDs well with a steady pitch so the outside image is stable. Around 300 it starts making sense to the brain, not earlier than that to me. If no GS until that point, PAPI + V/S are the tools, Mk II eyeball + V/S and a little gut when below.