GS and Aiming Point

[zedoscarro]

One question to all aviators around the world.
When performing an ILS approach, at the minima or a little before it, do you guys continue visually (of course) below the GS on a 3 to 1 case (3 red to 1 white)??
Or do you continue following the PAPIs on a 2 to 2 and flare so touching down a little after the aiming point?

My point is, a lot of Commanders tell me to touch on the aiming point, thus going for a 3 to 1 situation. Just a few tell me to go via the GS and also to brief the LDA using the GS.

Your opinions are gold! Thanx in advance :ok:

[9.G]

zedoscarro, as usual the only recommendation should be read your manual, I'm pretty sure it's all in there. Here's how we do it: we have a task sharing for PF/PNF for both manual and automated flight, put it simple who's head up and who's head down. After the transition to visual at or above the DA/MDA provided above 200 ft and PAPI is coinciding with the GP, follow PAPI till 200 ft thereafter aim for aiming point to touch down anywhere within the TDZ. We always brief LDA beyond the glide hence it's your performance criterium. Landing performance (ALD) even using the LPC isn't accurate it's rather test pilot landing which, you would agree, isn't achievable in normal OPS. This is valid for airbus :ok:

[sevenstrokeroll]

touching down abeam the gs antenna is actually tough. really good pilots, willing to smack it on can do it.

most can't. and they land a little longer...around 1500' down the runway (narrowbody).

there is a way to reduce speed and blend the flare just right to stay on GS and touchdown abeam the GS antenna...but you have to actually know what you are doing. see the book, "stick and rudder" and the ''stall down landing". You have to be really sharp in a jet to do this.

better a tiny bit long, than ducking the gs and ending up short

[Piltdown Man]

At most airfields, if you choose the correct PAPI's (some are set for big, long heavies) you follow both them and the Glideslope to the fixed distance markers where you'll do a flare and land. Ducking into 3 reds is as unacceptable as long flares/hold-offs which land you outside the touchdown zone. The reason for the first is that you may easily increase the ROD to something unacceptable, un-stabilise the approach and wack it in and the second is that not only do you invalidate your landing performance, you also increase the chances of a tailstrike. Exceptions? Plenty and these will be noted on the approach plates: Trondheim Rwy 27 for example. The radio glide is at 3.4˚ but the PAPIs are at 3˚. So operating here you would expect to end up "three reds" if you follow the radio glide slope.

And while we are here, you are only being paid to land on the centreline, at the right place and speed. There's no bonus for a greasy smooth landing. Just so long as the plane can be used again, any landing will do.

PM

[Runaway Gun]

PM, if you follow a 3.4 degree radio glide slope, with the PAPI's set at only 3 degrees, then won't they indicate that you are slightly high?

I could be wrong, just curious.

[Piltdown Man]

In the words of Homer Simpson - Dohh!

You are absolutely correct!

PM

[framer]

After 3 or four years of trying to get it right and trying new things my current approach seems to be working best for me. Once visual I just stay glued to the glidesplope (if I have one) with my eyes out about 60% of the time right down to 100ft, then I transition to 90% outside with glances in to make sure the airspeed isn't decaying and by being on slope at 100ft I find I'd be struggling to land long, at 50ft rad alt call I move my eyes from the aim point to the end of the strip and just fly it. I've given up on trying to put it on extra smooth and like the other poster said just put it in the right place at the right speed. Funny thing about that is that now I am often doing 'nice' touchdowns as well as getting it in the right place. That did take a few months to come right though. Not sure if that helps but it's my experience.

[framer]

ps can someone tell me how many feet vertcally one dot deviation is at 100ft, 200ft and 300ft? I used to know on a 3 degree slope but have forgotten, I know it is very very small, like 5 ft or something.

[misd-agin]

framer - I'm in the same boat you are. Thirty years ago I probably knew the answer. Today? I checked my 'who cares' file and it's not there. ;)

Here's a guess - 8' at 200'???

[sevenstrokeroll]

honest to gosh, it seems like some "BACK TO BASICS" airmanship work is needed.

first, read: "STick and Rudder" and look at the stuff on spot landings, stall down landings and so forth.

tells you how to aim...now I'm not saying you should really full stall a jet transport on landing, but you can reduce speed, blending the flare so you touchdown on or near your spot at the target airspeed (maybe ref minus five?).

''handling the big jets'

and
"fly the wing"

[c100driver]

If the PAPI is set for widebody aircraft, following the ILS GP will transition to 3R 1W at about 600' if you are flying a B737, flying a B747 will be 2R 2W all the way in.

[Green Guard]

framer one dot deviation is at 100ft, 200ft and 300ft?

If above GS = 10 ft, 20 ft and 30 ft
If below GS = 6.7 ft, 13.3 ft and 20 ft
for any other just use this one GS dev (ft)= HAT(ft) x GS dev° / GS°

PS.
2 dots above is not 0.5° but 0.6°
and 2 dots below is not 0.5° but 0.4°

zedoscarro One question to all aviators around the world.


If you are OK by your SOP to be 1 dot abv / blw for APP, the choice is yours

[sevenstrokeroll]

and if you really want to be good, look on the back of the jepp chart...you will see the exact poing the ILS glideslope will bring you...in terms of runway remaining after GS touchdown.

Remember boys and girls...if you want to make flying look as easy as Fred Astaire dances...you have to practice a whole lot

[MrWooby]

If you want some excellent reading on touchdown point, aim point, flare, approach paths etc, look at some of the articles on this website.

The Jacobson Flare (http://www.jacobsonflare.com/)

[b744FPEK]

2/2 or 3/1 can both right ,it depends on the position of the papi lights and GP antenna. before i go to a new airport ,i always check the airport data on this information.lets say if the papi is 1000 feet from the threshold and the aiming point maker are 400 meters, which is very commen ,three red and one white should be correct at 200 feet.

[framer]

Thanks Green Guard