Runway alignments for ILS landings

[FLEX1978 373]

He's confused mate getting approach minimums mixed up with autoland capability

[ryanbatc 12,770]

I guess I'm confused too. Autoland takes two requirements. The mode in the ILS, cat 3 in this case, and pilots who are authorized to perform it.

 

Where I work as ATC, we have to change our mode from cat 1 to cat 2 with the push of a button. If we don't do that they can't fly cat 2.

 

I assume it would be the same if we had cat 3 capability. But we don't.

 

In addition to that our lights must be set correctly - so

Something we have control over, not the pilots.

[g_precentralis 191]

And how Ap can recognize what button you pushed?

[Great Ozzie 101]

Where I work as ATC, we have to change our mode from cat 1 to cat 2 with the push of a button. If we don't do that they can't fly cat 2.

Ryan...

 

Are you referring to an "actual" CatII approach (with "actual" wx i.e. down to the 100'/1600-1200RVR mins) or are you referring to practice CatII in VFR conditions?

[ryanbatc 12,770]

I'm referring to a real world application.  Not practice.

 

And for what it's worth, any time we have pilots ask for CAT II for practice, we have to bypass cat 1 and select cat 2 on the ils panel.  So something is changing, whether it be the monitoring etc... but it's a component of the ils that says its "ok" to fly a cat II from what I know.

 

Maybe you guys are talking about FSX and how you can autoland at any airport with an ILS.  That's just not accurate in real life.

[g_precentralis 191]

No, we are talking about RW. Autoland can follow any ILS signal, no matter what you do in tower (unless you shut down ILS facility). There is no interaction between your button in tower and AP in aircraft.

[FLEX1978 373]

Instead of going round in circles I think some people should do a bit research. Ryan I am talking about real life here not FSX

 

Feels a bit like banging my head against a brick wall if anyone doesn't understand then don't take my word for it, kinda reminds of a certain pilots website where flight simmers argue with 10000 hour captains because they think they know what they are talking about.

 

here's a bit more info....

 

AUTOMATIC LANDING IN CAT I OR BETTER WEATHER CONDITIONS

 

The automatic landing system’s performance has been demonstrated on runways equipped with CAT II or CAT III approaches. However, automatic landing in CAT I or better weather conditions is possible on CAT I ground installations or on CAT II/III ground installations when ILS sensitive areas are not protected, if the following precautions are taken:

 

• The airline has checked that the ILS beam quality, and the effect of the terrain profile before the runway have no adverse effect on AP/FD guidance. In particular, the effect of terrain discontinuities within 300 meters before the runway threshold must be evaluated.

[Great Ozzie 101]

Maybe you guys are talking about FSX and how you can autoland at any airport with an ILS. That's just not accurate in real life.

You don't seem to have got the difference between a practice autolanding and a real one. You cannot do real autolanding on a CAT I system.

NASA ASRS Report 634380, October 2004 During rollout following certification required practice autoland procedure in dfw, MD80 turns aggressively to the right and only prompt action by the reporter avoided a runway excursion.

 

Can we perform autoland with ils cat1 signal? (from PPRuNe)

[ryanbatc 12,770]

You're telling me a 747 can do a cat 3c autoland without the autopilot?  The plane can't fly the ils to those CAT III mins if mode is Cat I - wouldn't be legal.  That's what I'm saying.  Therefore you can't do it... sorry that's my "practical" perspective on it.

 

edit: I read your pprune link.  They say it's theoretically possible to do a full autoland with CAT I.  Ok I didn't know that.  Still there's no way that could be legal.  The purpose of the categories is to have better monitoring (and lights) between each category, not to mention from a practical perspective, lower weather mins.  If you don't have the monitoring how can you fly a legal cat 2 or 3 for that matter?'

 

I've yet to see an aircraft fly our ILS, who wanted a cat II approach, and not ask "is cat II available?"  Well I guess I shouldn't say that... but they don't ask because we have it available when the weather goes to poop, it's on the ATIS.

 

Oops we got off topic

[Great Ozzie 101]

You guys are saying a 747 can do a cat3c full autoland, without autopilot, even if the ils is setup to cat I ?

No... that you can do an Autoland on an CatI ILS... (CATIIIc is something totally separate...)

[g_precentralis 191]

Yea, thats a great topic, and to quote one significant post:

An 'Autoland' is not the same thing as a Cat 2/3 approach. The aircrfat doesn't care whether visibility is good or bad, or whether the ILS is a CAT 1 or a CAT 3 installation, if you tell it to do an autoland, it will try and do one to the best of it's ability. It's ability to do so is affected by the exmaples of criteria you mention: G/S angle, no offset LLZ etc.

[FLEX1978 373]

You're telling me a 747 can do a cat 3c autoland without the autopilot?  The plane can't fly the ils to those CAT III mins if mode is Cat I.  That's what I'm saying.

 

edit: I read your pprune link.  They say it's theoretically possible to do a full autoland with CAT I.  Ok I didn't know that.  Still there's no way that could be legal.  The purpose of the categories is to have better monitoring (and lights) between each category, not to mention from a practical perspective, lower weather mins.  If you don't have the monitoring how can you fly a legal cat 2 or 3 for that matter?'

 

I've yet to see an aircraft fly our ILS, who wanted a cat II approach, and not ask "is cat II available?"  Well I guess I shouldn't say that... but they don't ask because we have it available when the weather goes to poop, it's on the ATIS.

 

Oops we got off topic

Ryan did you read the pprune link properly? It is not illegal, And I have mentioned numerous times I am talking from real world experience.

 

Forget the weather, autoland capability has nothing to do with weather.. You don't want to be landing in CATIII conditions on a CATI ILS however if you are above CATI minima it is perfectly legal to autoland, it is done everyday by multiple operators.

[ryanbatc 12,770]

No... that you can do an Autoland on an CatI ILS... (CATIIIc is something totally separate...)

 

Ok this is not what I'm talking about...  fair enough.

 

Now educate me.  A B747 is flying an ILS in VMC, it is setup for cat 1.  When they reach 200 ft agl, you're saying they don't have to disconnect A/P?  I thought it was a legal requirement to have cat 3c ability to have the airplane touchdown and rollout.  Or is the cat 3c just a type of approach that leads to touchdown and rollout?

 

And then my other question, since you guys seem to be in avionics or something...  you're saying we could just leave our CAT I ILS up and planes could fly it in bad weather to CAT II mins all day long?  Why do we even have a bypass switch then in the first place?

 

Oh, finally... I thought the point of cat 3c is to have the A/P fly the plane down to the runway.  I just always thought the two go hand it hand.  I thought it was a legal requirement that the plane do it...  (which from a logical perspective doesn't make sense - what if computer screwed up that's what the pilot is for).  So what is the point of 3c then?

 

p.s.  I'm not an instrument pilot (controllers don't know everything!) so this is interesting to me!

[g_precentralis 191]

No, you are confused between categories of ILS, reduced visibility operations and autoland capability of aircraft, which are separate things and works together to ensure safe landings.

[Great Ozzie 101]

A B747 is flying an ILS in VMC, it is setup for cat 1. When they reach 200 ft agl, you're saying they don't have to disconnect A/P?

From what I understand of the B747, this is correct.

Or is the cat 3c just a type of approach

A type of an approach that would permit legal landing with zero DA/DH and zero visibility.

you're saying we could just leave our CAT I ILS up and planes could fly it in bad weather to CAT II mins all day long? Why do we even have a bypass switch then in the first place?

No... definitely not... part of the "equation" is the appropriate ground facilities...

 

p.s. I'm not an instrument pilot (controllers don't know everything!) so this is interesting to me!

 

As a 'double I' we are not too far apart here! :Big grin: