Autoland CAT 1
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From: actually in ppruneland.
Autoland CAT 1
Hi, everybody I have a question that maybe sound silly but I wonder how to do it, lets asume you can accomplished with the requirements to do an ILS DME CATI approach auto land, ok What do you set on your app page DH or MDA?.. 
thank you
toby
thank you
toby
Last edited by toby320; 25th November 2009 at 12:44.
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From: Germany
Toby I assume you are talking about A320.
If I can remember it correctly if you enter a value in the DH fild of the APP page this value is referenced to the radio altimeter and if you put it in the MDA field it is referenced to the barometric altitude readout.
As you want to fly a standard ILS CAT I approach the DA is a barometric altitude and to get the correct indications and voice callouts setting the DA in the MDA field would be just right.
Above might be wrong, as it is long ago that I flew an Airbus...
If I can remember it correctly if you enter a value in the DH fild of the APP page this value is referenced to the radio altimeter and if you put it in the MDA field it is referenced to the barometric altitude readout.
As you want to fly a standard ILS CAT I approach the DA is a barometric altitude and to get the correct indications and voice callouts setting the DA in the MDA field would be just right.
Above might be wrong, as it is long ago that I flew an Airbus...
Thread Starter
Joined: Nov 2008
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From: actually in ppruneland.
yes, I'm talking about A320, but I don't find info relate it to this case in normal cat I approach you use mda as reference but I want to know what diference does it make in a AUTO LAND CAT I use as refeence MDA or DH.
Any information I would really appreciate it.
tks, toby.
Any information I would really appreciate it.
tks, toby.
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Greetings
I think that at MDA - 50ft the Autopilot will disengage, because NPAs are suppose to use MDA as a setting, and to be sure that From MDA and below the Approach is flown manually, .....
In anycase try it in the Sim
I think that at MDA - 50ft the Autopilot will disengage, because NPAs are suppose to use MDA as a setting, and to be sure that From MDA and below the Approach is flown manually, .....
In anycase try it in the Sim
Last edited by kijangnim; 25th November 2009 at 12:53. Reason: Typos
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If one does an auto coupled ILS approach in say CAT 3a conditions then the ILS Localiser Sensitive Area (LSA) will be safeguarded, and hence the risk of disruption to the signal reduced.
If you do the same approach to a CAT 1 ILS the LSA will not be safeguarded, nor will ATC increase approach separation.
You may not be concerned about this, but I thought I'd mention it.
Sir George Cayley
If you do the same approach to a CAT 1 ILS the LSA will not be safeguarded, nor will ATC increase approach separation.
You may not be concerned about this, but I thought I'd mention it.
Sir George Cayley
Joined: Feb 2005
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From: Correr es mi destino por no llevar papel
There's fundamental difference between ICAO definitions of DH/MDA and DH/MDA as entered into A320 FMGS.
On A320s I've flown (s/Nos around 1200) entering DH would arm autocallouts ("HUNDRED ABOVE" and "MINIMUMS") and "DH" display on PFD - with reference to radio altimeter. Setting MDA would merely display it on PFD and make alt digital readout turn yellow below it. It would have no bearing on LVP, autopilot or autoland capability whatsoever.
CAT 1 ILS has barometric altitude referenced minimum, therefore DA is entered into MDA field. If you fly by reference to QFE, then DH is inserted as MDA.
However, I'm only too glad that I was never allowed to use autoland on CAT 1 ILSes or autothrust while flying manually.
On A320s I've flown (s/Nos around 1200) entering DH would arm autocallouts ("HUNDRED ABOVE" and "MINIMUMS") and "DH" display on PFD - with reference to radio altimeter. Setting MDA would merely display it on PFD and make alt digital readout turn yellow below it. It would have no bearing on LVP, autopilot or autoland capability whatsoever.
CAT 1 ILS has barometric altitude referenced minimum, therefore DA is entered into MDA field. If you fly by reference to QFE, then DH is inserted as MDA.
However, I'm only too glad that I was never allowed to use autoland on CAT 1 ILSes or autothrust while flying manually.
Thread Starter
Joined: Nov 2008
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From: actually in ppruneland.
tks for your replies, I will keep trying to find some reference about this scenario I understand what cat I approach require in order to stablish a minimum but in a 320 if I want to try an autoland there is where my doubt comes on and I wonder if there is some restriction or something 
may be I'm not clear enough but if there some A320 expertise I will really appreciate his opinion.
many tks, toby.
may be I'm not clear enough but if there some A320 expertise I will really appreciate his opinion.
many tks, toby.
Per Ardua ad Astraeus
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From: UK
I know nothing of the dark and wondrous workings of the electric jet and what the autopilot will and won't let you do, but in my book (737) it is exactly as Captain Pugwash's mate says. Bug up for the Cat IIIx, advise ATC who, if you are lucky and they are not busy might give you a 'semi-protected' environment, and then allow the full automatics to proceed - with 'standard calls' - hovering like a fussy maitre-d' over the controls lest some infringement of the protected zone might cause an interesting diversion onto the grass. Common practice (not the grass) to get your mandatory 'minimum' landings to maintain qualification and for training. Normally works just fine.
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From: home
Cat 1 minima is referenced to baro alt whilst Cat 3 is referenced to radalt. Therefore if you fly a practice autoland it is down to you which minima you set but you are still bound by the MDA. (obviously). Personally on a good weather day I would set DH, on a poor weather day, where I have planned an autoland in case of possible deterioration I will set MDA if the airfield has not declared low viz ops.
Despite the fact some people believe the autopilot will disconnect at
MDA -50, the aircraft will quite happily autoland.
Despite the fact some people believe the autopilot will disconnect at
MDA -50, the aircraft will quite happily autoland.
Joined: Feb 2002
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From: location location
kijangnim
Take yourself off to a dark room and repeat 100 times
" I do not understand how an airbus works, I am a danger to myself and anyone who plays with my flight simulator".
You clearly have no knowledge of mda,da,dh,mdh,lnav,vnav,lvp,rnp etc etc.
Please keep your incorrect opinions to yourself and watch and learn from the sidelines.
Now read the posts!!!
Take yourself off to a dark room and repeat 100 times
" I do not understand how an airbus works, I am a danger to myself and anyone who plays with my flight simulator".
You clearly have no knowledge of mda,da,dh,mdh,lnav,vnav,lvp,rnp etc etc.
Please keep your incorrect opinions to yourself and watch and learn from the sidelines.
Now read the posts!!!
Joined: Oct 2009
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From: uk
As mentioned earlier, what you enter in the MCDU minima does not affect the landing capability of the aircraft at all. I have performed autoland many times in airfields with Cat 1 only and MDA set for the Cat 1 minima, purely for autoland currency. Obviously you have to have Cat 1 weather and be prepared to disconnect the AP at any stage if the aircraft is not doing as you would expect it to do.
Joined: Oct 2007
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From: Greece
Hi toby320, here is your answer,
You set the applicable CAT I minima on the MDA field.
You are allowed to perform an autoland (yes autopilots remain engaged in LOC GS modes even below MDA-50) in CAT I conditions or better and at least CAT II landing capability displayed in the FMA. If autoland light on take over manually (in CAT I conditions you most probably wil have visual references) or go around.
Take into acount LSA might not be protected and remember your CAT I minima is your decision altitude which means you have to go around if no visual references by this altitude.
By the way you are allowed to perform autoland under these conditions even in CAT I only installations.
Regards.
Edit: Wizzaird was a bit faster than me.
You set the applicable CAT I minima on the MDA field.
You are allowed to perform an autoland (yes autopilots remain engaged in LOC GS modes even below MDA-50) in CAT I conditions or better and at least CAT II landing capability displayed in the FMA. If autoland light on take over manually (in CAT I conditions you most probably wil have visual references) or go around.
Take into acount LSA might not be protected and remember your CAT I minima is your decision altitude which means you have to go around if no visual references by this altitude.
By the way you are allowed to perform autoland under these conditions even in CAT I only installations.
Regards.
Edit: Wizzaird was a bit faster than me.
Joined: Jun 2005
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From: London
Fair bit of confusion here. Even Boeing Obi Wan Kenobi BOAC felt he had to say something (nice to see you on an Airbus thread - yes I have gone to the dark side...).
Just to clarify it for toby 320:
1) LAND/FLARE/ROLLOUT will be displayed as long as you have selected an ILS approach and have ONE autopilot engaged
2) As long as the above is displayed the aircraft will autoland, REGARDLESS of whether you selected a DH or DA/MDA but you MUST have at least Cat II displayed on the FMA (based on systems availability)
3) Auto callouts will be armed regardless of selecting DH or DA/MDA. They will just be based on either baro alt or rad alt depending on which one you picked. There are additional callout modifications specific to each type of approach e.g. ONE HUNDRED as opposed to HUNDRED ABOVE if you picked NO DH (Cat IIIb).
So to go back to your original question, you can select a Cat I minimum in the MDA field of the MCDU and do an Autoland. Airbus recommends you select both autopilots if they are available. But it will work with one as long as no failures occur to downgrade the landing capability below Cat II (again, as displayed on FMA).
Beware of the ILS-sensitive area being not protected (see BOAC post)
P
Edit: both Wizaird and aristoclis were faster than me
Just to clarify it for toby 320:
1) LAND/FLARE/ROLLOUT will be displayed as long as you have selected an ILS approach and have ONE autopilot engaged
2) As long as the above is displayed the aircraft will autoland, REGARDLESS of whether you selected a DH or DA/MDA but you MUST have at least Cat II displayed on the FMA (based on systems availability)
3) Auto callouts will be armed regardless of selecting DH or DA/MDA. They will just be based on either baro alt or rad alt depending on which one you picked. There are additional callout modifications specific to each type of approach e.g. ONE HUNDRED as opposed to HUNDRED ABOVE if you picked NO DH (Cat IIIb).
So to go back to your original question, you can select a Cat I minimum in the MDA field of the MCDU and do an Autoland. Airbus recommends you select both autopilots if they are available. But it will work with one as long as no failures occur to downgrade the landing capability below Cat II (again, as displayed on FMA).
Beware of the ILS-sensitive area being not protected (see BOAC post)
P
Edit: both Wizaird and aristoclis were faster than me
