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FligtReporter
Topic Author
Posts: 516
Joined: Thu Sep 15, 2016 3:03 am

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 4:17 am

Hello respected gentlemen,

So I came across this video of an A320 which appears to be on final CATIII approach,however, at 100 feet or so the autopilot degrades the CAT III "DUAL" to CAT II as per what its mentioned in the description.

https://youtu.be/xQVfljH0a3E

Now all this while,I have been learning about CAT IIIB operations on ground and got myself familiar with my own homebase regarding the Low Visibility Conditions ,however, I totally forgot to pay attention to the very important part of these operations and that are Equipment and Crew.I"m glad I came across this video as I have no knowledge about the functions of the aircraft during Low Visibility conditions,all I know is that all three (AIRPORT, AIRCRAFT and CREW) should be equipped with required system and Training to carry out these operations.

So my questions regarding this particular video are these :

1. Does Autopilot decide what Approach to carry on with and it could degrade the ILS levels by itself ?

2. What is the so called DUAL ? by the sheer understanding of the word I presume its the second autopilot and if so are there multiple autopilots that function during CAT III operations ?

3.If such a glitch doesn't rectify even after a GO AROUND then what are the options left for the pilots..Divert ?

4.Have you ever encountered such a glitch while making a CAT III(A and B) approach and if so how did you recover from this glitch ?

Thank you very much !
 
CanukinUSA
Posts: 99
Joined: Sun Oct 25, 2020 5:06 pm

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 4:31 am

For Cat II/III approaches during snow storms the ILS Critical Area has to be maintained very clean. If there is any Snow in the Glideslope Critical Area in particular with a standard transmitter the Glide slope will end up out of tolerance and as a result there will be a NOTAM issued that the approach runway is not capable of CAT II and/or III approaches. CYWG (Winnipeg) is a good example of this. Check their NOTAMS this time of year when they are encountering snow storms.
The standard ILS Glideslope transmitter uses the ground in the critical area as part of it's antenna and the signal reflects off the ground which is affected by the snow on the ground during snow storms.
 
FligtReporter
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Posts: 516
Joined: Thu Sep 15, 2016 3:03 am

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 4:38 am

CanukinUSA wrote:
For Cat II/III approaches during snow storms the ILS Critical Area has to be maintained very clean. If there is any Snow in the Glideslope Critical Area in particular with a standard transmitter the Glide slope will end up out of tolerance and as a result there will be a NOTAM issued that the approach runway is not capable of CAT II and/or III approaches. CYWG (Winnipeg) is a good example of this. Check their NOTAMS this time of year when they are encountering snow storms.
The standard ILS Glideslope transmitter uses the ground in the critical area as part of it's antenna and the signal reflects off the ground which is affected by the snow on the ground during snow storms.


The above video is of Munich and I believe it does snow out there and given the criticality of these low visibility operations the snow could have interfered with the ground equipment thus messing up the whole approach.

Thanks for the explanation MrUSA
 
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Starlionblue
Posts: 20692
Joined: Fri Feb 27, 2004 9:54 pm

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 9:29 am

FligtReporter wrote:
Hello respected gentlemen,

So I came across this video of an A320 which appears to be on final CATIII approach,however, at 100 feet or so the autopilot degrades the CAT III "DUAL" to CAT II as per what its mentioned in the description.

https://youtu.be/xQVfljH0a3E

Now all this while,I have been learning about CAT IIIB operations on ground and got myself familiar with my own homebase regarding the Low Visibility Conditions ,however, I totally forgot to pay attention to the very important part of these operations and that are Equipment and Crew.I"m glad I came across this video as I have no knowledge about the functions of the aircraft during Low Visibility conditions,all I know is that all three (AIRPORT, AIRCRAFT and CREW) should be equipped with required system and Training to carry out these operations.

So my questions regarding this particular video are these :

1. Does Autopilot decide what Approach to carry on with and it could degrade the ILS levels by itself ?

2. What is the so called DUAL ? by the sheer understanding of the word I presume its the second autopilot and if so are there multiple autopilots that function during CAT III operations ?

3.If such a glitch doesn't rectify even after a GO AROUND then what are the options left for the pilots..Divert ?

4.Have you ever encountered such a glitch while making a CAT III(A and B) approach and if so how did you recover from this glitch ?

Thank you very much !


1. The autopilot does not decide on the approach. On Airbus for an ILS, you always engage both autopilots. So if you don't touch anything, and nothing stops working, the aircraft will perform an autoland in CAT III DUAL mode. The CAT XXX mode displayed on the FMA is the highest level that the aircraft can currently perform.

In the "normal" case, where the airport has at CAT I or better conditions, you'd just disengage the autopilots at some point, and the mode would revert to CAT I.

Degradation could be due to some failure. Loss of one of the beams for more than seven seconds, failure of radar altimeter, or a number of other things. The system reverted to CAT II but obviously, with that visibility, you can't land with only CAT II capability.

2. It is called DUAL because both autopilots are in use. On the FMA, you can read AP1+2. And in the centre of the FCU (glareshield) you can see both AP1 and AP2 lights are on. If one of the autopilots stopped working during CAT III DUAL, the system would revert to CAT III SINGLE, but the autoland could still go ahead. (On A350, "CAT" has been replaced with "LAND" in the mode terminology.)

CAT III DUAL mode gives "fail operational" capability, meaning even if you lose an autopilot you can still continue. CAT III SINGLE gives "fail passive" capability, meaning if you lose the (remaining) autopilot you could not continue the approach.

3. Given the conditions, CAT II is not possible. If the issue can't be fixed, divert or wait for visibility to improve.

4. I have never seen such a glitch but they do happen. What to do really depends on where you are in the approach. If you're at 1500 feet and revert to CAT II, you could quickly check if the conditions allow CAT II minima. If yes, amend the minima use those. If you're under 1000 feet you'd just go around. No time to start troubleshooting and revising the plan. Go around and see what you can do once you've climbed out. In many cases, it would just be a question of resetting a system or, as mentioned above, waiting for issues with ground equipment to be resolved. (Or waiting for the weather to improve if that is forecast.)

Go around is always the "safe" option. At a safe altitude, you have time to deal with things.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
FligtReporter
Topic Author
Posts: 516
Joined: Thu Sep 15, 2016 3:03 am

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 10:09 am

Starlionblue wrote:
FligtReporter wrote:
Hello respected gentlemen,

So I came across this video of an A320 which appears to be on final CATIII approach,however, at 100 feet or so the autopilot degrades the CAT III "DUAL" to CAT II as per what its mentioned in the description.

https://youtu.be/xQVfljH0a3E

Now all this while,I have been learning about CAT IIIB operations on ground and got myself familiar with my own homebase regarding the Low Visibility Conditions ,however, I totally forgot to pay attention to the very important part of these operations and that are Equipment and Crew.I"m glad I came across this video as I have no knowledge about the functions of the aircraft during Low Visibility conditions,all I know is that all three (AIRPORT, AIRCRAFT and CREW) should be equipped with required system and Training to carry out these operations.

So my questions regarding this particular video are these :

1. Does Autopilot decide what Approach to carry on with and it could degrade the ILS levels by itself ?

2. What is the so called DUAL ? by the sheer understanding of the word I presume its the second autopilot and if so are there multiple autopilots that function during CAT III operations ?

3.If such a glitch doesn't rectify even after a GO AROUND then what are the options left for the pilots..Divert ?

4.Have you ever encountered such a glitch while making a CAT III(A and B) approach and if so how did you recover from this glitch ?

Thank you very much !


1. The autopilot does not decide on the approach. On Airbus for an ILS, you always engage both autopilots. So if you don't touch anything, and nothing stops working, the aircraft will perform an autoland in CAT III DUAL mode. The CAT XXX mode displayed on the FMA is the highest level that the aircraft can currently perform.

In the "normal" case, where the airport has at CAT I or better conditions, you'd just disengage the autopilots at some point, and the mode would revert to CAT I.

Degradation could be due to some failure. Loss of one of the beams for more than seven seconds, failure of radar altimeter, or a number of other things. The system reverted to CAT II but obviously, with that visibility, you can't land with only CAT II capability.

2. It is called DUAL because both autopilots are in use. On the FMA, you can read AP1+2. And in the centre of the FCU (glareshield) you can see both AP1 and AP2 lights are on. If one of the autopilots stopped working during CAT III DUAL, the system would revert to CAT III SINGLE, but the autoland could still go ahead. (On A350, "CAT" has been replaced with "LAND" in the mode terminology.)

CAT III DUAL mode gives "fail operational" capability, meaning even if you lose an autopilot you can still continue. CAT III SINGLE gives "fail passive" capability, meaning if you lose the (remaining) autopilot you could not continue the approach.

3. Given the conditions, CAT II is not possible. If the issue can't be fixed, divert or wait for visibility to improve.

4. I have never seen such a glitch but they do happen. What to do really depends on where you are in the approach. If you're at 1500 feet and revert to CAT II, you could quickly check if the conditions allow CAT II minima. If yes, amend the minima use those. If you're under 1000 feet you'd just go around. No time to start troubleshooting and revising the plan. Go around and see what you can do once you've climbed out. In many cases, it would just be a question of resetting a system or, as mentioned above, waiting for issues with ground equipment to be resolved. (Or waiting for the weather to improve if that is forecast.)

Go around is always the "safe" option. At a safe altitude, you have time to deal with things.


Thank you so very much Mr Starlion for your point by point answers, I profoundly appreciate your time and patience with all my constant queries now a days ,you are like an aviation guru who always has answers to my questions.

Thanks again :)
 
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Starlionblue
Posts: 20692
Joined: Fri Feb 27, 2004 9:54 pm

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 11:08 am

FligtReporter wrote:
Starlionblue wrote:
FligtReporter wrote:
Hello respected gentlemen,

So I came across this video of an A320 which appears to be on final CATIII approach,however, at 100 feet or so the autopilot degrades the CAT III "DUAL" to CAT II as per what its mentioned in the description.

https://youtu.be/xQVfljH0a3E

Now all this while,I have been learning about CAT IIIB operations on ground and got myself familiar with my own homebase regarding the Low Visibility Conditions ,however, I totally forgot to pay attention to the very important part of these operations and that are Equipment and Crew.I"m glad I came across this video as I have no knowledge about the functions of the aircraft during Low Visibility conditions,all I know is that all three (AIRPORT, AIRCRAFT and CREW) should be equipped with required system and Training to carry out these operations.

So my questions regarding this particular video are these :

1. Does Autopilot decide what Approach to carry on with and it could degrade the ILS levels by itself ?

2. What is the so called DUAL ? by the sheer understanding of the word I presume its the second autopilot and if so are there multiple autopilots that function during CAT III operations ?

3.If such a glitch doesn't rectify even after a GO AROUND then what are the options left for the pilots..Divert ?

4.Have you ever encountered such a glitch while making a CAT III(A and B) approach and if so how did you recover from this glitch ?

Thank you very much !


1. The autopilot does not decide on the approach. On Airbus for an ILS, you always engage both autopilots. So if you don't touch anything, and nothing stops working, the aircraft will perform an autoland in CAT III DUAL mode. The CAT XXX mode displayed on the FMA is the highest level that the aircraft can currently perform.

In the "normal" case, where the airport has at CAT I or better conditions, you'd just disengage the autopilots at some point, and the mode would revert to CAT I.

Degradation could be due to some failure. Loss of one of the beams for more than seven seconds, failure of radar altimeter, or a number of other things. The system reverted to CAT II but obviously, with that visibility, you can't land with only CAT II capability.

2. It is called DUAL because both autopilots are in use. On the FMA, you can read AP1+2. And in the centre of the FCU (glareshield) you can see both AP1 and AP2 lights are on. If one of the autopilots stopped working during CAT III DUAL, the system would revert to CAT III SINGLE, but the autoland could still go ahead. (On A350, "CAT" has been replaced with "LAND" in the mode terminology.)

CAT III DUAL mode gives "fail operational" capability, meaning even if you lose an autopilot you can still continue. CAT III SINGLE gives "fail passive" capability, meaning if you lose the (remaining) autopilot you could not continue the approach.

3. Given the conditions, CAT II is not possible. If the issue can't be fixed, divert or wait for visibility to improve.

4. I have never seen such a glitch but they do happen. What to do really depends on where you are in the approach. If you're at 1500 feet and revert to CAT II, you could quickly check if the conditions allow CAT II minima. If yes, amend the minima use those. If you're under 1000 feet you'd just go around. No time to start troubleshooting and revising the plan. Go around and see what you can do once you've climbed out. In many cases, it would just be a question of resetting a system or, as mentioned above, waiting for issues with ground equipment to be resolved. (Or waiting for the weather to improve if that is forecast.)

Go around is always the "safe" option. At a safe altitude, you have time to deal with things.


Thank you so very much Mr Starlion for your point by point answers, I profoundly appreciate your time and patience with all my constant queries now a days ,you are like an aviation guru who always has answers to my questions.

Thanks again :)


Thank you but I don't see myself as a guru. I have flown with many pilots, and simmed with many instructors, who have forgotten more than I have ever known.

I really don't mind answering directed, specific questions, especially when they come in a neat list with numbers and spacing. If nothing else, every now and then I have to double-check something in a manual. Scenario-based revision is best. :rotfl:
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
FligtReporter
Topic Author
Posts: 516
Joined: Thu Sep 15, 2016 3:03 am

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 11:32 am

Starlionblue wrote:
FligtReporter wrote:
Starlionblue wrote:

1. The autopilot does not decide on the approach. On Airbus for an ILS, you always engage both autopilots. So if you don't touch anything, and nothing stops working, the aircraft will perform an autoland in CAT III DUAL mode. The CAT XXX mode displayed on the FMA is the highest level that the aircraft can currently perform.

In the "normal" case, where the airport has at CAT I or better conditions, you'd just disengage the autopilots at some point, and the mode would revert to CAT I.

Degradation could be due to some failure. Loss of one of the beams for more than seven seconds, failure of radar altimeter, or a number of other things. The system reverted to CAT II but obviously, with that visibility, you can't land with only CAT II capability.

2. It is called DUAL because both autopilots are in use. On the FMA, you can read AP1+2. And in the centre of the FCU (glareshield) you can see both AP1 and AP2 lights are on. If one of the autopilots stopped working during CAT III DUAL, the system would revert to CAT III SINGLE, but the autoland could still go ahead. (On A350, "CAT" has been replaced with "LAND" in the mode terminology.)

CAT III DUAL mode gives "fail operational" capability, meaning even if you lose an autopilot you can still continue. CAT III SINGLE gives "fail passive" capability, meaning if you lose the (remaining) autopilot you could not continue the approach.

3. Given the conditions, CAT II is not possible. If the issue can't be fixed, divert or wait for visibility to improve.

4. I have never seen such a glitch but they do happen. What to do really depends on where you are in the approach. If you're at 1500 feet and revert to CAT II, you could quickly check if the conditions allow CAT II minima. If yes, amend the minima use those. If you're under 1000 feet you'd just go around. No time to start troubleshooting and revising the plan. Go around and see what you can do once you've climbed out. In many cases, it would just be a question of resetting a system or, as mentioned above, waiting for issues with ground equipment to be resolved. (Or waiting for the weather to improve if that is forecast.)

Go around is always the "safe" option. At a safe altitude, you have time to deal with things.


Thank you so very much Mr Starlion for your point by point answers, I profoundly appreciate your time and patience with all my constant queries now a days ,you are like an aviation guru who always has answers to my questions.

Thanks again :)


Thank you but I don't see myself as a guru. I have flown with many pilots, and simmed with many instructors, who have forgotten more than I have ever known.

I really don't mind answering directed, specific questions, especially when they come in a neat list with numbers and spacing. If nothing else, every now and then I have to double-check something in a manual. Scenario-based revision is best. :rotfl:


For me to getting to learn form experts like you is the best experience I've ever had online because prior to being here I received all my info from scouring the websites and trying to learn about it through various other channels.I have to say its very helpful when you have someone who deal with the situation you have questions and queries about,because people like you can help people like me so better by mitigating the time I would otherwise spend on various websites which at the end of the day may be confusing and may not even be accurate.

Just like before getting to learn about CAT IIIB I thought of the visibility as the RVR...I remember when the captain didn't take my queries regarding the visibility and I was asked to deboard...The first thing I did was to ask an airport employee about the visibility and he told me it was 45-50 meters and I thought that's what the RVR was :lol: I'm so embarrassed how dumb I was.

But I guess if it weren't for my curiosity (and Dumbness lol),to know more about something I found fascinating,I wouldn't have learnt all about it that I have in these few days and you know Mr Starlion the best thing about this learning experience from you and Mr.Galaxy,Mr Flyzone,Mr IAH and all other aviation experts is that not only I learnt it from people who have expertise in dealing with this tech but who also helped me understand the concepts better by always clarifying or elaborating it for me to understand it better.

I can't thank you all enough,I never really patronized this website before meeting you all but since I've met you all I feel so good coming here and shooting my questions because people like you are so kind and paitent to take my queries and questions and answer them...So for me all of you are Gurus !
 
Woodreau
Posts: 2077
Joined: Mon Sep 24, 2001 6:44 am

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 11:50 am

The airplane never decides.

As you’ve discovered - there are three parts to Cat III ILS approaches - the runway, the airplane and the crew. Each introduces their own variable which determines the actual minimums used for a cat III approach

The mode annunciation on the FMA Cat 3 DUAL signals the airplanes capability to the crew. On a Normal VFR day with CAVOK. Conditions the airplane will indicate CAT 3 DUAL as long as the parameters the aircraft is monitoring satisfy the criteria the plane is using to determine whether it’s can operate in a CAT 3 Fail operational status.

If the crew forgot to arm the second autopilot, the FMA would never annunciate CAT 3 DUAL it will only annunciate CAT 3 SINGLE.

since its cavok the crew has the runway in sight the PF disconnects the autopilot to land. As soon as the autopilot is disconnected. There is an autopilot disconnect aural There is a triple click to indicate change in status and the CAT 3 DUAL on the FMA reverts to CAT 1 as the airplane determines now that it is incapable of doing an autoland because the crew took that ability away from the plane by disconnecting the autopilot.

Training runs exercise and thought drills by giving us different combinations of reported RVR values, airplane equipment status, runway approaches, runway approach lighting and then asking if we can be begin the approach? What are the minimums? Is the cat 3 Fail Operational or fail passive?

It is interesting seeing how minimums change for the same runway at one airport as things like centerline lights notam’ed inop- changes that cat 3 to a special authorization cat 2.

Or there is a 1 line NOTAM buried in the 1-inch thick stack of NOTAMs for the flight that states “localizer not suitable for rollout guidance” for a runway at the destination airport. That changes the minimums for that runway on that cat II/III approach plate from 300 RVR to 1800RVR since the autopilot needs the localizer to provide the rollout guidance to keep the airplane on the runway centerline.

The airplane will say CAT 3 DUAL the whole time because it can’t read NOTAMs and doesn’t know it’s not going to not have rollout guidance after it lands.


Anyways after all that.... I still have yet in my 16 years as an airline pilot to fly a cat 3 approach to an autoland. I’ve don a few cat 1s to an autoland.

Even with the blizzards that is occurring this week all over the United States. The minimums never got below cat 1 even during the height of the blizzard at the airports I flew to.
Last edited by Woodreau on Tue Feb 16, 2021 12:05 pm, edited 1 time in total.
Bonus animus sit, ab experientia. Quod salvatum fuerit de malis usu venit judicium.
 
User avatar
Starlionblue
Posts: 20692
Joined: Fri Feb 27, 2004 9:54 pm

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 11:51 am

Woodreau wrote:

Or there is a 1 line NOTAM buried in the 1-inch thick stack of NOTAMs for the flight that states “localizer not suitable for rollout guidance” for a runway at the destination airport. That changes the minimums for that runway on that cat II/III approach plate from 300 RVR to 1800RVR since the autopilot needs the localizer to provide the rollout guidance to keep the airplane on the runway centerline.


It's always the important NOTAMs that seem to be short and easy to miss.

If only we could implement a NOTAM system that wasn't based on 1920s teletype technology, so we could have nice things like boldface, italics, and little bell icons instead of just capital letters...

But I digress. :x



FligtReporter wrote:
Starlionblue wrote:
FligtReporter wrote:

Thank you so very much Mr Starlion for your point by point answers, I profoundly appreciate your time and patience with all my constant queries now a days ,you are like an aviation guru who always has answers to my questions.

Thanks again :)


Thank you but I don't see myself as a guru. I have flown with many pilots, and simmed with many instructors, who have forgotten more than I have ever known.

I really don't mind answering directed, specific questions, especially when they come in a neat list with numbers and spacing. If nothing else, every now and then I have to double-check something in a manual. Scenario-based revision is best. :rotfl:


For me to getting to learn form experts like you is the best experience I've ever had online because prior to being here I received all my info from scouring the websites and trying to learn about it through various other channels.I have to say its very helpful when you have someone who deal with the situation you have questions and queries about,because people like you can help people like me so better by mitigating the time I would otherwise spend on various websites which at the end of the day may be confusing and may not even be accurate.

Just like before getting to learn about CAT IIIB I thought of the visibility as the RVR...I remember when the captain didn't take my queries regarding the visibility and I was asked to deboard...The first thing I did was to ask an airport employee about the visibility and he told me it was 45-50 meters and I thought that's what the RVR was :lol: I'm so embarrassed how dumb I was.

But I guess if it weren't for my curiosity (and Dumbness lol),to know more about something I found fascinating,I wouldn't have learnt all about it that I have in these few days and you know Mr Starlion the best thing about this learning experience from you and Mr.Galaxy,Mr Flyzone,Mr IAH and all other aviation experts is that not only I learnt it from people who have expertise in dealing with this tech but who also helped me understand the concepts better by always clarifying or elaborating it for me to understand it better.

I can't thank you all enough,I never really patronized this website before meeting you all but since I've met you all I feel so good coming here and shooting my questions because people like you are so kind and paitent to take my queries and questions and answer them...So for me all of you are Gurus !



I can understand the captain on your flight. He's a busy guy and he is at work. This, on the other hand, is an online forum. No one is forcing us to answer.

As you might have seen, my tagline in the forum is, "There are no stupid questions, but there are a lot of inquisitive idiots." . I'll answer questions, depending on how they're being asked. ;) You seem to have done some prep work before asking, which counts for a lot.



There are plenty of approachable books for the layman on these technical matters if you are interested. Flying the Big Jets by Stanley Stewart is a good read.**

Image

If you're more into watching, Mentour Pilot is an excellent channel, run by an SAS training captain. He keeps things very accessible and interesting, with good graphics and clear narration. )

Image

https://www.youtube.com/channel/UCwpHKu ... gmMdexB3ow


**Note: Flying the Big Jets should not be confused with Handling the Big Jets by DP Davies. The latter is considered a seminal book in the industry, but it is not a beginner text.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
FligtReporter
Topic Author
Posts: 516
Joined: Thu Sep 15, 2016 3:03 am

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 12:09 pm

Woodreau wrote:
The airplane never decides.

As you’ve discovered - there are three parts to Cat III ILS approaches - the runway, the airplane and the crew. Each introduces their own variable which determines the actual minimums used for a cat III approach

The mode annunciation on the FMA Cat 3 DUAL signals the airplanes capability to the crew. On a Normal VFR day with CAVOK. Conditions the airplane will indicate CAT 3 DUAL as long as the parameters the aircraft is monitoring satisfy the criteria the plane is using to determine whether it’s can operate in a CAT 3 Fail operational status.

If the crew forgot to arm the second autopilot, the FMA would never annunciate CAT 3 DUAL it will only annunciate CAT 3 SINGLE.

since its cavok the crew has the runway in sight the PF disconnects the autopilot to land. As soon as the autopilot is disconnected. There is an autopilot disconnect aural There is a triple click to indicate change in status and the CAT 3 DUAL on the FMA reverts to CAT 1 as the airplane determines now that it is incapable of doing an autoland because the crew took that ability away from the plane by disconnecting the autopilot.

Training runs exercise and thought drills by giving us different combinations of reported RVR values, airplane equipment status, runway approaches, runway approach lighting and then asking if we can be begin the approach? What are the minimums? Is the cat 3 Fail Operational or fail passive?

It is interesting seeing how minimums change for the same runway at one airport as things like centerline lights notam’ed inop- changes that cat 3 to a special authorization cat 2.

Or there is a 1 line NOTAM buried in the 1-inch thick stack of NOTAMs for the flight that states “localizer not suitable for rollout guidance” for a runway at the destination airport. That changes the minimums for that runway on that cat II/III approach plate from 300 RVR to 1800RVR since the autopilot needs the localizer to provide the rollout guidance to keep the airplane on the runway centerline.

The airplane will say CAT 3 DUAL the whole time because it can’t read NOTAMs and doesn’t know it’s not going to not have rollout guidance after it lands.


Anyways after all that.... I still have yet in my 16 years as an airline pilot to fly a cat 3 approach to an autoland. I’ve don a few cat 1s to an autoland.

Even with the blizzards that is occurring this week all over the United States. The minimums never got below cat 1 even during the height of the blizzard at the airports I flew to.


Thank you very much for yet another detailed explanation Mr Woodreau !
 
FligtReporter
Topic Author
Posts: 516
Joined: Thu Sep 15, 2016 3:03 am

Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 12:13 pm

Starlionblue wrote:
Woodreau wrote:

Or there is a 1 line NOTAM buried in the 1-inch thick stack of NOTAMs for the flight that states “localizer not suitable for rollout guidance” for a runway at the destination airport. That changes the minimums for that runway on that cat II/III approach plate from 300 RVR to 1800RVR since the autopilot needs the localizer to provide the rollout guidance to keep the airplane on the runway centerline.


It's always the important NOTAMs that seem to be short and easy to miss.

If only we could implement a NOTAM system that wasn't based on 1920s teletype technology, so we could have nice things like boldface, italics, and little bell icons instead of just capital letters...

But I digress. :x



FligtReporter wrote:
Starlionblue wrote:

Thank you but I don't see myself as a guru. I have flown with many pilots, and simmed with many instructors, who have forgotten more than I have ever known.

I really don't mind answering directed, specific questions, especially when they come in a neat list with numbers and spacing. If nothing else, every now and then I have to double-check something in a manual. Scenario-based revision is best. :rotfl:


For me to getting to learn form experts like you is the best experience I've ever had online because prior to being here I received all my info from scouring the websites and trying to learn about it through various other channels.I have to say its very helpful when you have someone who deal with the situation you have questions and queries about,because people like you can help people like me so better by mitigating the time I would otherwise spend on various websites which at the end of the day may be confusing and may not even be accurate.

Just like before getting to learn about CAT IIIB I thought of the visibility as the RVR...I remember when the captain didn't take my queries regarding the visibility and I was asked to deboard...The first thing I did was to ask an airport employee about the visibility and he told me it was 45-50 meters and I thought that's what the RVR was :lol: I'm so embarrassed how dumb I was.

But I guess if it weren't for my curiosity (and Dumbness lol),to know more about something I found fascinating,I wouldn't have learnt all about it that I have in these few days and you know Mr Starlion the best thing about this learning experience from you and Mr.Galaxy,Mr Flyzone,Mr IAH and all other aviation experts is that not only I learnt it from people who have expertise in dealing with this tech but who also helped me understand the concepts better by always clarifying or elaborating it for me to understand it better.

I can't thank you all enough,I never really patronized this website before meeting you all but since I've met you all I feel so good coming here and shooting my questions because people like you are so kind and paitent to take my queries and questions and answer them...So for me all of you are Gurus !



I can understand the captain on your flight. He's a busy guy and he is at work. This, on the other hand, is an online forum. No one is forcing us to answer.

As you might have seen, my tagline in the forum is, "There are no stupid questions, but there are a lot of inquisitive idiots." . I'll answer questions, depending on how they're being asked. ;) You seem to have done some prep work before asking, which counts for a lot.



There are plenty of approachable books for the layman on these technical matters if you are interested. Flying the Big Jets by Stanley Stewart is a good read.**

Image

If you're more into watching, Mentour Pilot is an excellent channel, run by an SAS training captain. He keeps things very accessible and interesting, with good graphics and clear narration. )

Image

https://www.youtube.com/channel/UCwpHKu ... gmMdexB3ow


**Note: Flying the Big Jets should not be confused with Handling the Big Jets by DP Davies. The latter is considered a seminal book in the industry, but it is not a beginner text.


I have subscribed to the channel of the Montour Pilot and I like his videos he also talks about tech issues and past crashes as well but its not easy to have him comment back to your query lol

Oh and thanks for the book idea Mr Starlion..I will look it up for this Book and see if it's available.
 
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Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 2:02 pm

BTW Mr Starlion both the Captain and First officer on my special flight were Ladies :lol:

It was a Girl power flight and the cabin crew made it sure to include this in their pre departure announcement.
 
Thenoflyzone
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Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 4:23 pm

Woodreau wrote:

It is interesting seeing how minimums change for the same runway at one airport as things like centerline lights notam’ed inop- changes that cat 3 to a special authorization cat 2.

Or there is a 1 line NOTAM buried in the 1-inch thick stack of NOTAMs for the flight that states “localizer not suitable for rollout guidance” for a runway at the destination airport. That changes the minimums for that runway on that cat II/III approach plate from 300 RVR to 1800RVR since the autopilot needs the localizer to provide the rollout guidance to keep the airplane on the runway centerline.

The airplane will say CAT 3 DUAL the whole time because it can’t read NOTAMs and doesn’t know it’s not going to not have rollout guidance after it lands.


In this particular situation, the controller shouldn't clear you for a CATIII approach. After all, us controllers need to read the NOTAMs too.

This reminds me of something that happened at my airport 2 years ago.

We were very close to our CATI minimums, almost CATII, but hadn't activated it yet, as planes were still landing with the CATI minimums. ( To activate CATII, we still needed to start the backup generator, advise the airport authority we are in CATII ops, so they can close off a few vehicle roads that didn't meet the requirements, etc and so on). We hadn't even broadcast CATII on the ATIS yet, or advised approach control that we were officially CATII.

Anyways, a regional US Embraer Jet shows up on final, calls us (TWR), and tells us he's flying the ILS CATII approach. I checked with APP control to see if they accidentally cleared him for a CATII, but they say no. Needless to say, I get back to the pilot and tell him, "CATII isn’t active yet, Fly the CATI minimums, and I'll talk to you later once you clear the active.”

After he landed, I told him that he can't just decide on his own to fly the CATII approach. The airport wasn't even set up yet for CAT II ops. The ATIS never said the CATII approach was in use. APP control never told you to plan for the CATII, and most important of all, you, as a pilot, never told ATC you were planning on doing the CATII. Not to mention that here in Canada, the separation on final is greatly increased between 2 arrivals when doing CATII or III ops, in order to protect the ILS critical area, and the plane in question was following another by 3-4 nm. (During CATII, spacing needs to increase to around 8nm between landers in order to protect the ILS signal for each lander.)

A lot of holes in the swiss cheese lineup up that day. Anyways, that crew learned a valuable lesson on CATII/III ops that day.

Woodreau wrote:
The airplane never decides.

As you’ve discovered - there are three parts to Cat III ILS approaches - the runway, the airplane and the crew. Each introduces their own variable which determines the actual minimums used for a cat III approach



Exactly this. Just because the plane and the crew can do CATII doesn't mean the runway can at that moment.

Lesson of the day: if your planning on flying a CATII or III approach, advise ATC. They might tell you something you weren’t aware of (related to NOTAMs or otherwise)
Last edited by Thenoflyzone on Tue Feb 16, 2021 4:37 pm, edited 2 times in total.
us Air Traffic Controllers have a good record, we haven't left one up there yet !!
 
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Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 4:36 pm

Hi everyone,

So in the evening I saw an Airbus A320N make a visual approach at RWY 09 now that's the end of the RWY where our localizer is and I have always considered RWY 09 as the visual approach RWY and thats because everytime I have spotted airplanes landing on that side is either when the winds are westward or it is a clear day and I was wondering because my airport has just one localizer then does it mean airplanes landing on RWY 09 can't use the ILS at all ?

Because I have seen bigger airports with these orange localizers at both the ends of their RWYS and I'm curious to know about the operational scenario at an airport like mine where we just have one localizer and one of those red and white glideslope Tower close to the touchdown zone of RWY 27.
 
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Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 4:51 pm

Thenoflyzone wrote:
Woodreau wrote:

It is interesting seeing how minimums change for the same runway at one airport as things like centerline lights notam’ed inop- changes that cat 3 to a special authorization cat 2.

Or there is a 1 line NOTAM buried in the 1-inch thick stack of NOTAMs for the flight that states “localizer not suitable for rollout guidance” for a runway at the destination airport. That changes the minimums for that runway on that cat II/III approach plate from 300 RVR to 1800RVR since the autopilot needs the localizer to provide the rollout guidance to keep the airplane on the runway centerline.

The airplane will say CAT 3 DUAL the whole time because it can’t read NOTAMs and doesn’t know it’s not going to not have rollout guidance after it lands.


In this particular situation, the controller shouldn't clear you for a CATIII approach. After all, us controllers need to read the NOTAMs too.

This reminds me of something that happened at my airport 2 years ago.

We were very close to our CATI minimums, almost CATII, but hadn't activated it yet, as planes were still landing with the CATI minimums. ( To activate CATII, we still needed to start the backup generator, advise the airport authority we are in CATII ops, so they can close off a few vehicle roads that didn't meet the requirements, etc and so on). We hadn't even broadcast CATII on the ATIS yet, or advised approach control that we were officially CATII.

Anyways, a regional US Embraer Jet shows up on final, calls us (TWR), and tells us he's flying the ILS CATII approach. I checked with APP control to see if they accidentally cleared him for a CATII, but they say no. Needless to say, I get back to the pilot and tell him, "CATII isn’t active yet, Fly the CATI minimums, and I'll talk to you later once you clear the active.”

After he landed, I told him that he can't just decide on his own to fly the CATII approach. The airport wasn't even set up yet for CAT II ops. The ATIS never said the CATII approach was in use. APP control never told you to plan for the CATII, and most important of all, you, as a pilot, never told ATC you were planning on doing the CATII. Not to mention that here in Canada, the separation on final is greatly increased between 2 arrivals when doing CATII or III ops, in order to protect the ILS critical area, and the plane in question was following another by 3-4 nm. (During CATII, spacing needs to increase to around 8nm between landers in order to protect the ILS signal for each lander.)

A lot of holes in the swiss cheese lineup up that day. Anyways, that crew learned a valuable lesson on CATII/III ops that day.

Woodreau wrote:
The airplane never decides.

As you’ve discovered - there are three parts to Cat III ILS approaches - the runway, the airplane and the crew. Each introduces their own variable which determines the actual minimums used for a cat III approach



Exactly this. Just because the plane and the crew can do CATII doesn't mean the runway can at that moment.

Lesson of the day: if your planning on flying a CATII or III approach, advise ATC. They might tell you something you weren’t aware of (related to NOTAMs or otherwise)


WooW this is an intresting story Mr Flyzone...I took a screenshot of this.So the CATII/III are like those functions that need to be turned on by the ATC for the pilots to use them and they need permission prior to using them and I believe its the ATCs who are the real king of the Airport lol.

If the ATC doesn't see the weather apt for CAT II/III operations they won't put them in use and have the authority to guide the pilots with the suitable procedures during the given weather conditions and they are bound to follow the instructions by the ATC period.It would be great to read more of such stories.

Thanks for sharing it Mr Flyzone !
 
CanukinUSA
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Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 6:32 pm

As you can see there are a whole bunch of personnel and facilities that have to be up and running to do Cat II and/or Cat III approaches safely.
But I have a question about the situation mentioned by Thenoflyzone post before, who in Canada now has to make the call to get the airport set up for Cat II/III operations? Do you not plan ahead if the weather is close to Cat I limits and start setting up everything you can for possible Cat II/III operations just in case? Given that weather forecasting is quite often an inexact science in particular for forecasting cloud base and visibility it sounds to me that a bunch of personnel where sleeping at the switch in that situation.
A further note on one of my previous posts is that to detect ILS signal issues getting out of tolerance there are "far field" signal monitors that will set off alarms in the Control Tower and possibly shut down the ILS transmitters or switch to the backup transmitters for the ILS if certain conditions are met. If the ILS shuts down the aircraft in most cases will detect the signal loss and indicate to the pilot by the CAT II/III annunciation on the flight deck. I will let the air traffic controllers on this forum describe more details on the alarms they have as they are probably more familiar with them then I am. Many aircraft will also switch to Inertial navigation for short signal or equipment interruptions to continue the approach. During the landing flare on final approach the aircraft is not using the Glideslope any more for vertical guidance due to it not being usable close to the ground and is only using the localizer to stay on the runway centerline and the radio altimeter for vertical height information to adjust the auto throttles to idle and flare for landing.
If all procedures are followed correctly the probability of an aircraft getting in some of the situations mentioned before are very low. The only place the average line pilot will likely experience these issues in his/her career is probably during training in a flight simulator. Most of the flight simulators now have the capability to do Cat III training including giving the simulator instructor malfunctions to insert like having vehicles or aircraft entering the ILS critical areas and many system failures on the aircraft itself.
I spent a number of years working for the world's largest simulator manufacturer in Canada and it was quite a challenge to get the weather conditions simulated properly set up for training. For a Cat IIIB approach you do not see very much as you approach the runway. The simulation of the correct runway lights and in particular the runway threshold, centerline and touchdown zone lights becomes very important as that is all you can see on these approaches. Even things like the halos produced by the runway lights during different visibilities becomes important to simulate correctly to properly train the flight crews for these approaches.
Some of the airport simulator scenes available also simulate the Surface Movement Guidance and Control Systems for training for places like Munich (EDDM) if customers purchase the option. One of the hardest things to accomplish after landing in Cat III conditions that happened when Cat III approaches were started was that flight crews had trouble finding their way off the runway and of course tied up the runway for aircraft behind them. The British were pioneers in all weather operations due to the issues they encountered often at their major airport EGLL (London Heathrow). That is why there are now high speed exit centerline lights on many Cat III runways. Europe has been usually ahead of North America in All Weather Operations due to the climate occurring at their major airports. In North America the major airports with all weather issues are places like Seattle Tacoma (KSEA) and Vancouver (CYVR) particularly during the winter. The challenge is to make the simulated system user friendly to the instructor as he is not a ground air traffic controller like is present in the control tower and has students to watch during training sessions.
 
Thenoflyzone
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Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 8:50 pm

CanukinUSA wrote:
But I have a question about the situation mentioned by Thenoflyzone post before, who in Canada now has to make the call to get the airport set up for Cat II/III operations? Do you not plan ahead if the weather is close to Cat I limits and start setting up everything you can for possible Cat II/III operations just in case? Given that weather forecasting is quite often an inexact science in particular for forecasting cloud base and visibility it sounds to me that a bunch of personnel where sleeping at the switch in that situation.


I think the official wording in the documents is CDM (collaborative decision making), but unofficially, tower makes the call. If anything, APP control and management are always reluctant going to CATII, because the AAR (airport arrival rate) goes down, so the airlines aren't too happy. Basically, if they can land with CATI minimums, we often try to avoid going into CATII unnecessarily. I believe one of the main carriers at my airport have to fly a CATII if it is published as the active approach on the ATIS, even if the minimums are still OK for CATI. This can create delays, due to increased spacing on final, and therefore, management/APP control isn't too keen on doing that.

CanukinUSA wrote:
A further note on one of my previous posts is that to detect ILS signal issues getting out of tolerance there are "far field" signal monitors that will set off alarms in the Control Tower and possibly shut down the ILS transmitters or switch to the backup transmitters for the ILS if certain conditions are met.


We have a lighting panel in the tower, that controls all lights at the airport (apart from those on the apron). From there, we can monitor everything needed for CATII ops. (Generator running, ALSF-2 lights on, HIRL, TDZL, CL, etc) If one of these components fail, we will get an automatic alarm in the tower advising us of the failure. We have status lights on the CATII page of the panel advising us if a certain element is necessary or not for CATII operations.

Same thing for the ILS signal. If one of the components fails, we will be one of first to notice, and there will be an alarm going off in the tower.

CanukinUSA wrote:
That is why there are now high speed exit centerline lights on many Cat III runways.


Not most. All.

Exit centerline lights (doesn't have to be high speed) are a requirement for CATIII approaches. During CATIII ops, you basically need centerline lights from touchdown all the way to the apron, just before you start to maneuver for parking.
us Air Traffic Controllers have a good record, we haven't left one up there yet !!
 
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Re: The Magic of "CAT IIIB"

Tue Feb 16, 2021 11:50 pm

FligtReporter wrote:
Hi everyone,

So in the evening I saw an Airbus A320N make a visual approach at RWY 09 now that's the end of the RWY where our localizer is and I have always considered RWY 09 as the visual approach RWY and thats because everytime I have spotted airplanes landing on that side is either when the winds are westward or it is a clear day and I was wondering because my airport has just one localizer then does it mean airplanes landing on RWY 09 can't use the ILS at all ?

Because I have seen bigger airports with these orange localizers at both the ends of their RWYS and I'm curious to know about the operational scenario at an airport like mine where we just have one localizer and one of those red and white glideslope Tower close to the touchdown zone of RWY 27.


As far as I can see, VILK09 has no ILS. However, there is a VOR approach.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 1:19 am

Starlionblue wrote:
FligtReporter wrote:
Hi everyone,

So in the evening I saw an Airbus A320N make a visual approach at RWY 09 now that's the end of the RWY where our localizer is and I have always considered RWY 09 as the visual approach RWY and thats because everytime I have spotted airplanes landing on that side is either when the winds are westward or it is a clear day and I was wondering because my airport has just one localizer then does it mean airplanes landing on RWY 09 can't use the ILS at all ?

Because I have seen bigger airports with these orange localizers at both the ends of their RWYS and I'm curious to know about the operational scenario at an airport like mine where we just have one localizer and one of those red and white glideslope Tower close to the touchdown zone of RWY 27.


As far as I can see, VILK09 has no ILS. However, there is a VOR approach.


Ok MrStarlion but at airports where they have both the runways ILS equipped (Like both ends)..how does it work there ?
 
e38
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 1:46 am

FligtReporter wrote:
Hi everyone,

"everytime I have spotted airplanes landing on that side is either when the winds are westward"


FligtReporter, just a minor point, in aviation, winds are generally referenced based on the direction from which they are blowing. For example, if Runway 09 is in use, the winds are probably going to be from the east or "easterly" winds. Sometimes takeoffs and landings with a tailwind are required for operational purposes--conditions permitting--but in general, landings and takeoffs with a headwind is preferred.

Also, you stated, "because my airport has just one localizer then does it mean airplanes landing on RWY 09 can't use the ILS at all ?"

I'm not sure I understand the question, but yes, that is correct. If the only ILS approach at your airport is the ILS27, then you cannot fly an ILS approach to Runway 09.

and your other question, "at airports where they have both the runways ILS equipped (Like both ends)..how does it work there ?"

In general, they are considered separate ILS approaches, with specific frequencies, identifiers, and transmitters.

e38
 
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 2:22 am

e38 wrote:
FligtReporter wrote:
Hi everyone,

"everytime I have spotted airplanes landing on that side is either when the winds are westward"


FligtReporter, just a minor point, in aviation, winds are generally referenced based on the direction from which they are blowing. For example, if Runway 09 is in use, the winds are probably going to be from the east or "easterly" winds. Sometimes takeoffs and landings with a tailwind are required for operational purposes--conditions permitting--but in general, landings and takeoffs with a headwind is preferred.

Also, you stated, "because my airport has just one localizer then does it mean airplanes landing on RWY 09 can't use the ILS at all ?"

I'm not sure I understand the question, but yes, that is correct. If the only ILS approach at your airport is the ILS27, then you cannot fly an ILS approach to Runway 09.

and your other question, "at airports where they have both the runways ILS equipped (Like both ends)..how does it work there ?"

In general, they are considered separate ILS approaches, with specific frequencies, identifiers, and transmitters.

e38


Thank you very much Mr e38 for your point by point answers and yes you understood my questions perfectly..all that you understood is exactly what I intended to know and I will remember the aviation terminology with respect to the direction of the winds ! Thanks for teaching me something new Mr e38 !
 
GalaxyFlyer
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 2:58 am

There is, for every localizer (LOC, lateral guidance) a “back course” signal radiated, just the mirror of the front course. Some airports, very infrequently now, had approaches using the back course as the lateral navigation signal. A few US airports even radiated a glide slope with the back course. There are lots of reasons this wasn’t the greatest idea, but it worked.

If there is an ILS for each direction, the tower controller has to switch the ILS when changing runways.
 
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 3:20 am

GalaxyFlyer wrote:
There is, for every localizer (LOC, lateral guidance) a “back course” signal radiated, just the mirror of the front course. Some airports, very infrequently now, had approaches using the back course as the lateral navigation signal. A few US airports even radiated a glide slope with the back course. There are lots of reasons this wasn’t the greatest idea, but it worked.

If there is an ILS for each direction, the tower controller has to switch the ILS when changing runways.


Oh Thats new I didn't know about this "Back Course" thing..that sounds intresting. Thanks for the info Mr Galaxy !
 
e38
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 3:31 am

FligtReporter, this has nothing to do with your question about ILS approach, but with regard to your statement above:

"I remember when the captain didn't take my queries regarding the visibility and I was asked to deboard..."

I am very sorry you were treated like that by the crew.

On my aircraft, If a passenger comes into the flight deck during the boarding process or while deplaning and they are interested in any aspect of our operation--the route, the weather, our schedules, the aircraft, etc.--I have never asked them to leave the flight deck, tried to hurry them along, or asked them to deplane the aircraft. I will chat with them until all their questions are answered. If I have to connect to another aircraft or have a subsequent commitment, I will speak with the passenger as long as I can, and then respectfully explain my reason for having to excuse myself.

There was a reply, "I can understand the captain on your flight. He is a busy guy and he is at work."

My philosophy is that if a passenger is interested in the operation, then to take the time to talk to that person and answer their questions, well, that IS part of my work. I'm never too busy to visit with our passengers, especially those interested in the operational aspect of the flight.

FligtReporter, I hope on your next flight the crew treats you very well and answers your questions.

e38
 
CanukinUSA
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 4:52 am

Correction: There is not a useable back course signal emitted from most ILS localizers anymore. In order to cut down on signal reflections and bends most of the new ILS do not transmit a usable signal in the opposite direction for the back course approach anymore.
At many airports there is now only one transmitter used with two antennas at opposite ends of the runway on the same frequency. The controller switches antennas to use the ILS approach for the runway that is in use only.
 
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 5:40 am

e38 wrote:
FligtReporter, this has nothing to do with your question about ILS approach, but with regard to your statement above:

"I remember when the captain didn't take my queries regarding the visibility and I was asked to deboard..."

I am very sorry you were treated like that by the crew.

On my aircraft, If a passenger comes into the flight deck during the boarding process or while deplaning and they are interested in any aspect of our operation--the route, the weather, our schedules, the aircraft, etc.--I have never asked them to leave the flight deck, tried to hurry them along, or asked them to deplane the aircraft. I will chat with them until all their questions are answered. If I have to connect to another aircraft or have a subsequent commitment, I will speak with the passenger as long as I can, and then respectfully explain my reason for having to excuse myself.

There was a reply, "I can understand the captain on your flight. He is a busy guy and he is at work."

My philosophy is that if a passenger is interested in the operation, then to take the time to talk to that person and answer their questions, well, that IS part of my work. I'm never too busy to visit with our passengers, especially those interested in the operational aspect of the flight.

FligtReporter, I hope on your next flight the crew treats you very well and answers your questions.

e38


I'm sure you must be a really cool captain or first officer to fly with Mr E38...actually on this flight the crew had to prepare for the flight back to Bombay...and I was not allowed into the cockpit, I just stood at the alley after everyone had deplaned and requested the cabin crew to put my questions to the captain and she was kind enough to answer my first question which was the confirmation of the landing being CAT IIIB but when I requested the crew to convey my second question which was regarding the visibility the crew lady told me that the captain had asked me to leave as they had to prepare for their next flight.

And honestly I didn't mind it Mr E38...there have been way more worse experiences where I'v been even shouted at by the pilots,where I had taken a photo of the inside of the cockpit and the captain said "Please Get Out ! you are not allowed to take pictures" ..I didn't even take their faces in my photo i was just taking the photo of the panel and he snatched my phone and deleted that photo...I was very upset the way he behaved but I guess he was busy and may be he was just following his company's policy.

Though I don't know why most of the Indian pilots, I've had these short encounters with, have been grumpy but I don't blame them..for I feel may be Its my overly inquisitive nature which annoys them and I guess Its my fault that I somehow end up being a subject of discomfort to them which is never my intention but it just so happens inadvertently in my quest to knowing more and more.

Thank you so much Mr E38 for your time and patience for my questions and and I'm sure pax who fly with you are the lucky ones to have you as their Cap or FO !
 
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 1:20 pm

So this one is related to Horizontal visibility based on my understanding of the term and by limited superficial measurements on Google earth based on my personal observation out of the aircraft window.

Now while we were approaching the RWY I could see earthly establishments like buildings,homes and other infrastructure and the fog was moderate,however,just before the touchdown (Around 1 something NM) is where it got blindingly thick and thrust reverse time frame and till we passed the taxiway D,however, as we were passing by taxiway "E"(Last taxiway from RWY 27 and first from 09 ) I noticed that it was not as foggy as compared to the scene at previous taxiways and as per my google earth measurements based on the ground object adjacent to the Taxiway E,I found the visibility must be approx 100 meters from the RWY centerline or most possibly from where I could see it,however, on the METAR of the time of my landing I could see the Horizontal Visibility to be (0000) which I believe means 0 and due to this I find this scenario a little baffling.

So I'd love to have your insight regarding the following -:

1. What is the tool behind calculating the horizontal visibility of a given area and where is it located at the airport ?

2.Are the measurements for Horizontal visibility based on a particular zone of the RWY or the whole of airport premises ? because I presume may be its measured only at the touchdown zone given the criticality of that area during the low visibility conditions and procedures but I could be wrong.

Thanks again !
 
IAHFLYR
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 2:21 pm

Thenoflyzone wrote:
In this particular situation, the controller shouldn't clear you for a CATIII approach. After all, us controllers need to read the NOTAMs too.

This reminds me of something that happened at my airport 2 years ago.

We were very close to our CATI minimums, almost CATII, but hadn't activated it yet, as planes were still landing with the CATI minimums. ( To activate CATII, we still needed to start the backup generator, advise the airport authority we are in CATII ops, so they can close off a few vehicle roads that didn't meet the requirements, etc and so on). We hadn't even broadcast CATII on the ATIS yet, or advised approach control that we were officially CATII.

Anyways, a regional US Embraer Jet shows up on final, calls us (TWR), and tells us he's flying the ILS CATII approach. I checked with APP control to see if they accidentally cleared him for a CATII, but they say no. Needless to say, I get back to the pilot and tell him, "CATII isn’t active yet, Fly the CATI minimums, and I'll talk to you later once you clear the active.”

After he landed, I told him that he can't just decide on his own to fly the CATII approach. The airport wasn't even set up yet for CAT II ops. The ATIS never said the CATII approach was in use. APP control never told you to plan for the CATII, and most important of all, you, as a pilot, never told ATC you were planning on doing the CATII. Not to mention that here in Canada, the separation on final is greatly increased between 2 arrivals when doing CATII or III ops, in order to protect the ILS critical area, and the plane in question was following another by 3-4 nm. (During CATII, spacing needs to increase to around 8nm between landers in order to protect the ILS signal for each lander.)


Interesting as down in the U.S., we do not advertise CAT II/III approaches on the ATIS, nor do we as approach controllers issue the clearance using the phrase CAT II/III within the approach clearance, just "cleared ILS Runway 9 approach" and then include any RVR values. The pilot knows his/her minima and if they cannot accept the approach due to that then they tell us and we go to a different plan. Often when a crew gets on the arrival controller frequency with low weather mins they'll ask for the RVR and which runway has the nights reported value, then we attempt to sequence them to that runway if at all possible which with three parallel runways where I worked and all accepting arrivals (equip operational etc.,) that task is not all that difficult.

Speaking of arrival rates, yes they might be reduced some, but on a visual day the airport is able to land say 100/hour on a low weather day it may drop down to 72/hour. Not to say that is not insignificant because it is however, much of that reduction may be based on airport layout and any dependency departures have with the arrival runways even though the runways may not intersect. Extended runway centerlines have an impact when protecting for possible missed approach and the missed would fly across the centerline of a departing runway, have to protect for that possibility though rare.
Any views shared are strictly my own and do not a represent those of any former employer.
 
IAHFLYR
Posts: 4351
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 2:40 pm

FligtReporter wrote:

1. What is the tool behind calculating the horizontal visibility of a given area and where is it located at the airport ?

2.Are the measurements for Horizontal visibility based on a particular zone of the RWY or the whole of airport premises ? because I presume may be its measured only at the touchdown zone given the criticality of that area during the low visibility conditions and procedures but I could be wrong.

Thanks again !


1. Prevailing visibility is is a measurement of the greatest distance visible throughout at least half of the horizon, not necessarily continuously. Airports with ASOS/AWOS they provide that, other airports would have a certified weather observation station where the person goes out and finds known reference points such as buildings, antennas etc., and takes that distance at the visibility. The last line of defense would be a tower controller who would be a limited weather observer for taking weather observations in much the same manner.

2. When speaking of RVR yes, the transmissonmeter takes the distance for a particular part of or the entire runway which can be quite a bit different value for the same runway. If there is only touchdown zone RVR available then that is for the entire runway. When there are mid and rollout transmissionmeters then those provide the value within those specific zones on the runway. All the RVR readings are important though touchdown would be the deciding factor.

As a side note, FAA Order 7110.65 states:

Issue current touchdown RVR/RVV for the runway(s) in use:

1. When prevailing visibility is 1 mile or less regardless of the value indicated.

2. When RVR/RVV indicates a reportable value regardless of the prevailing visibility.

Hope that answers your question.
Any views shared are strictly my own and do not a represent those of any former employer.
 
FligtReporter
Topic Author
Posts: 516
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 2:51 pm

IAHFLYR wrote:
FligtReporter wrote:

1. What is the tool behind calculating the horizontal visibility of a given area and where is it located at the airport ?

2.Are the measurements for Horizontal visibility based on a particular zone of the RWY or the whole of airport premises ? because I presume may be its measured only at the touchdown zone given the criticality of that area during the low visibility conditions and procedures but I could be wrong.

Thanks again !


1. Prevailing visibility is is a measurement of the greatest distance visible throughout at least half of the horizon, not necessarily continuously. Airports with ASOS/AWOS they provide that, other airports would have a certified weather observation station where the person goes out and finds known reference points such as buildings, antennas etc., and takes that distance at the visibility. The last line of defense would be a tower controller who would be a limited weather observer for taking weather observations in much the same manner.

2. When speaking of RVR yes, the transmissonmeter takes the distance for a particular part of or the entire runway which can be quite a bit different value for the same runway. If there is only touchdown zone RVR available then that is for the entire runway. When there are mid and rollout transmissionmeters then those provide the value within those specific zones on the runway. All the RVR readings are important though touchdown would be the deciding factor.

As a side note, FAA Order 7110.65 states:

Issue current touchdown RVR/RVV for the runway(s) in use:

1. When prevailing visibility is 1 mile or less regardless of the value indicated.

2. When RVR/RVV indicates a reportable value regardless of the prevailing visibility.

Hope that answers your question.



Thanks Mr IAH !
 
Thenoflyzone
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 3:50 pm

IAHFLYR wrote:

Interesting as down in the U.S., we do not advertise CAT II/III approaches on the ATIS, nor do we as approach controllers issue the clearance using the phrase CAT II/III within the approach clearance, just "cleared ILS Runway 9 approach" and then include any RVR values.


That's because the CATII or III approach charts in the US are named ILS RWY XX (CATII & III). So you don't need to say what is in parenthesis when clearing the guy for an approach.

That's not how approach charts are written in Canada (or Europe/Asia, and everywhere else for that matter). All CATII & III approach charts mention CAT II or III in the name of the approach. Ex. "ILS CATII RWY XX" (In Europe/Asia, it's "CATII ILS RWY XX). So we have to say it when we clear a plane for the approach.

The rule is the same in Canada and in the US, obviously. When issuing an approach clearance, you have to specify the name of the approach procedure as published on the approach chart. But because of the parenthesis in the US, you don't need to say CATII or III, but here in Canada (and elsewhere), we do.

This is also why most CATII/III approaches have their own approach chart, and aren't published on the same CATI chart. And also why when the G/S is unserviceable, you can't simply say "cleared LOC app rwy XX". You must say "cleared ILS approach rwy XX, G/S unusable". Unless of course a LOC approach chart exists.

(I worked as an APP controller for 10 years before making the switch for a nicer office ;) )

https://www.faa.gov/air_traffic/publica ... ion_8.html

Section 8. Approach Clearance Procedures
APPROACH CLEARANCE
Clear aircraft for “standard” or “special” instrument approach procedures only.
To require an aircraft to execute a particular instrument approach procedure, specify in the approach clearance the name of the approach as published on the approach chart. Where more than one procedure is published on a single chart and a specific procedure is to be flown, amend the approach clearance to specify execution of the specific approach to be flown. If only one instrument approach of a particular type is published, the approach needs not be identified by the runway reference.


Between me and you, the way we do it here in Canada is the safer of the two. What if a pilot landing at IAH hasn't read all his NOTAMs, doesn't know that a certain ILS CATIII approach is U/S. No info on ATIS (as you state), not a single ATC mentions CATIII in approach clearance, and yet the pilot is flying CATIII, and doesn't or forgets to mention it to tower. He'll land thinking CATIII protections are there, when they aren't.

By having ATC mention the words CATII or III in the approach clearance (and also publishing it on the ATIS), you're adding a good safety net in the entire system.
Last edited by Thenoflyzone on Wed Feb 17, 2021 4:18 pm, edited 4 times in total.
us Air Traffic Controllers have a good record, we haven't left one up there yet !!
 
FligtReporter
Topic Author
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 4:10 pm

Before getting to my latest question I wanna sincerely thank Mr.Flyzone,Mr E38,Mr Galaxy,Mr Starlion,Mr USA,Mr IAH,Mr Woodreau and all other highly learned aviation experts.

Having learnt about the ILS CAT IIIB and other categories and also about the weather and myriads of various other aspects of Low visibility operations and different factors that constitute a successful execution of this unique procedure with respect to the equipments on the ground,I am now curious about the system that is installed in the aircraft which makes the aircraft compatible with the airport that has the ILS CAT II/III.

I have already learnt that there are three pre requisites for a successful CAT IIIB operation and they are :-: AIRPORT, AIRPLANE and the TRAINED PILOTS.

I remember at the very beginning of this thread I came across a comment where someone had mentioned "All Modern aircrafts have this tech" or something similar to that and having done a little reading about this issue I figured that the aircraft needs to have the required tech to synchronize with the system on ground to be able to carry out a successful Low Visibility Operation and I also learnt that not all aircrafts have this system...I mean may be I'm reading an older article and now all the aircrafts are pre installed with CAT III system before being delivered but here are my questions regarding the Aircraft aspect of it all -:

1. Is the autolanding system,and all the other systems in relation to Low visibility conditions, pre installed or the airlines have to pay extra and get their aircrafts equip with it ?

2. If the Aircraft is equipped with Low Visibility system then are there different systems for different Categories ? or for instance if an Aircraft has the best category of all i.e CAT IIIB then that system takes care of it all ?

3.What is the price difference should an airline get its aircraft equipped with such tech with the original price of an aircraft ?

Thanks again !
 
jjairbus
Posts: 10
Joined: Sat May 16, 2020 1:42 pm

Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 5:18 pm

Thenoflyzone wrote:
IAHFLYR wrote:

Interesting as down in the U.S., we do not advertise CAT II/III approaches on the ATIS, nor do we as approach controllers issue the clearance using the phrase CAT II/III within the approach clearance, just "cleared ILS Runway 9 approach" and then include any RVR values.


That's because the CATII or III approach charts in the US are named ILS RWY XX (CATII & III). So you don't need to say what is in parenthesis when clearing the guy for an approach.

That's not how approach charts are written in Canada (or Europe/Asia, and everywhere else for that matter). All CATII & III approach charts mention CAT II or III in the name of the approach. Ex. "ILS CATII RWY XX" (In Europe/Asia, it's "CATII ILS RWY XX). So we have to say it when we clear a plane for the approach.

The rule is the same in Canada and in the US, obviously. When issuing an approach clearance, you have to specify the name of the approach procedure as published on the approach chart. But because of the parenthesis in the US, you don't need to say CATII or III, but here in Canada (and elsewhere), we do.

This is also why most CATII/III approaches have their own approach chart, and aren't published on the same CATI chart. And also why when the G/S is unserviceable, you can't simply say "cleared LOC app rwy XX". You must say "cleared ILS approach rwy XX, G/S unusable". Unless of course a LOC approach chart exists.


I'm flying in A32S in Europe so I haven't got any experience in flying in the US or Canada. But checking my company charts for the US airports we only have one chart per ILS runway which includes minimas from CATIII through to LOC. Our approach charts for the US airports seem to be very close to their counterparts for Canadian or European airports.

And as a pilot I have to say that in Europe I don't remember being cleared anything else than ILS approach, whether it has been clear skies or 75 meter RVR. Only once I remember ATC mentioning CATIII approach and it was due to the rapidly and unexpectedly changing weather. Though I have to say that during 3,5 years of commercial flying there has been maybe 10 times actual CATII/III weather on my flights.

As pilots we're interested in making sure that low visibility procedures are in force, what the actual RVR and weather is, checking that the runway is validated for CAT3 ops (list on our EFB), NOTAMs and then we decide which approach we fly. Usually LVPs are mentioned in ATIS and the ATC keeps us informed about RVR and lets us decide what we do. We don't report which minima we're using and ATC sequences the traffic as per their own procedures.
Airbus driver from Europe
 
IAHFLYR
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 5:43 pm

Thenoflyzone wrote:
Between me and you, the way we do it here in Canada is the safer of the two. What if a pilot landing at IAH hasn't read all his NOTAMs, doesn't know that a certain ILS CATIII approach is U/S. No info on ATIS (as you state), not a single ATC mentions CATIII in approach clearance, and yet the pilot is flying CATIII, and doesn't or forgets to mention it to tower. He'll land thinking CATIII protections are there, when they aren't.

By having ATC mention the words CATII or III in the approach clearance (and also publishing it on the ATIS), you're adding a good safety net in the entire system.


While I fully support a huge safety net and breaking any and all of those nasty chains which create incidents/accidents I will say that we've got plenty of safety within the system.

Using your example above, the approach controller would know if CAT III for a specific runway was out, then we'd not be using the runway with RVR requiring CAT III ops. The tower Sup and TRACON Sup in addition to Traffic Management Unit personnel would also have adjusted the flow rate due to a runway being out of the mix and told the controllers we are landing Runway X and Y. I know for a fact the few times when this would happen, the tower Sup would turn the ILS around to the other end so they could not fly the approach. Should all those precautions fail then you've got a tower and ground controller who would know approaches to that runway were not happening so there would be no need to protect the CAT III hold line on the taxiway. Do all airport ATC functions operate in that manner, probably not, but I'm pretty sure all large airports where CAT II/III approaches are authorized are similar.

In 36 years of ATC with 32 of them working in a tower as well as TRACON when some of us were still dual qualified, I cannot think of many times when the pilot checked on with the tower during low visibility conditions and told me they were flying a CAT III approach. Most often they would tell the approach controller they were flying a CAT III auto-land and the tower when the weather was good and they were flying it from proficiency, and I get that clearly.

But I do wish a worldwide standard would be set and followed regardless of what states set it. Just like us using "position and hold" for a bazillion years before finally changing over to the rest of the world with "line up and wait".

Hey, a better office is always good.....sounds like I did much the same though was required to remain current.
Any views shared are strictly my own and do not a represent those of any former employer.
 
FligtReporter
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 5:43 pm

jjairbus wrote:
Thenoflyzone wrote:
IAHFLYR wrote:

Interesting as down in the U.S., we do not advertise CAT II/III approaches on the ATIS, nor do we as approach controllers issue the clearance using the phrase CAT II/III within the approach clearance, just "cleared ILS Runway 9 approach" and then include any RVR values.


That's because the CATII or III approach charts in the US are named ILS RWY XX (CATII & III). So you don't need to say what is in parenthesis when clearing the guy for an approach.

That's not how approach charts are written in Canada (or Europe/Asia, and everywhere else for that matter). All CATII & III approach charts mention CAT II or III in the name of the approach. Ex. "ILS CATII RWY XX" (In Europe/Asia, it's "CATII ILS RWY XX). So we have to say it when we clear a plane for the approach.

The rule is the same in Canada and in the US, obviously. When issuing an approach clearance, you have to specify the name of the approach procedure as published on the approach chart. But because of the parenthesis in the US, you don't need to say CATII or III, but here in Canada (and elsewhere), we do.

This is also why most CATII/III approaches have their own approach chart, and aren't published on the same CATI chart. And also why when the G/S is unserviceable, you can't simply say "cleared LOC app rwy XX". You must say "cleared ILS approach rwy XX, G/S unusable". Unless of course a LOC approach chart exists.


I'm flying in A32S in Europe so I haven't got any experience in flying in the US or Canada. But checking my company charts for the US airports we only have one chart per ILS runway which includes minimas from CATIII through to LOC. Our approach charts for the US airports seem to be very close to their counterparts for Canadian or European airports.

And as a pilot I have to say that in Europe I don't remember being cleared anything else than ILS approach, whether it has been clear skies or 75 meter RVR. Only once I remember ATC mentioning CATIII approach and it was due to the rapidly and unexpectedly changing weather. Though I have to say that during 3,5 years of commercial flying there has been maybe 10 times actual CATII/III weather on my flights.

As pilots we're interested in making sure that low visibility procedures are in force, what the actual RVR and weather is, checking that the runway is validated for CAT3 ops (list on our EFB), NOTAMs and then we decide which approach we fly. Usually LVPs are mentioned in ATIS and the ATC keeps us informed about RVR and lets us decide what we do. We don't report which minima we're using and ATC sequences the traffic as per their own procedures.



Just 10 times in 3,5 years !! ..Daymn...Here almost all mornings from Dec to Jan are CAT II/IIIB :lol:
 
IAHFLYR
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 5:56 pm

jjairbus wrote:
As pilots we're interested in making sure that low visibility procedures are in force, what the actual RVR and weather is, checking that the runway is validated for CAT3 ops (list on our EFB), NOTAMs and then we decide which approach we fly. Usually LVPs are mentioned in ATIS and the ATC keeps us informed about RVR and lets us decide what we do. We don't report which minima we're using and ATC sequences the traffic as per their own procedures.


I will use IAH as my example as I'm most familiar with it, though a standardization was gaining momentum at a number of HUB airports across the U.S. when I retired in 2012. We have a number of approaches such as ILS, ILS, (SA CAT I), ILS (SA CAT I/II), RNAV (GPS), RNAV (RNP) and GLS. Far too many for us simple minded controllers to memorize or look up in the information display we have at the control position. To mitigate that issue, all the approaches have the exact same lateral and vertical tracks so I could care less what the exact procedure is you fly just so you fly it precisely due to having simultaneous independent, dual/triple ops happening.

Some of us were pushing for a simple "cleared Runway 27 approach" and you fly whatever minima you want to fly. While I have not looked around at many other airport procedures, I know that KDFW and KATL are on a similar if not exact same lateral/vertical tracks.
Any views shared are strictly my own and do not a represent those of any former employer.
 
jjairbus
Posts: 10
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Re: The Magic of "CAT IIIB"

Wed Feb 17, 2021 8:27 pm

IAHFLYR wrote:
I will use IAH as my example as I'm most familiar with it, though a standardization was gaining momentum at a number of HUB airports across the U.S. when I retired in 2012. We have a number of approaches such as ILS, ILS, (SA CAT I), ILS (SA CAT I/II), RNAV (GPS), RNAV (RNP) and GLS. Far too many for us simple minded controllers to memorize or look up in the information display we have at the control position. To mitigate that issue, all the approaches have the exact same lateral and vertical tracks so I could care less what the exact procedure is you fly just so you fly it precisely due to having simultaneous independent, dual/triple ops happening.

Some of us were pushing for a simple "cleared Runway 27 approach" and you fly whatever minima you want to fly. While I have not looked around at many other airport procedures, I know that KDFW and KATL are on a similar if not exact same lateral/vertical tracks.


Yes, I've had that impression too. ATC wants us to be somewhere and we try to be there as precisely as we can. Depending on the situation we will choose the correct minima that will allow us to do that and if we're not able to do something we'll inform ATC. Of course it's good airmanship to confirm if anyone involved seems to be doing something out of the ordinary or there's any doubt on how to proceed.
Airbus driver from Europe
 
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Starlionblue
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Re: The Magic of "CAT IIIB"

Thu Feb 18, 2021 12:07 am

FligtReporter wrote:
Before getting to my latest question I wanna sincerely thank Mr.Flyzone,Mr E38,Mr Galaxy,Mr Starlion,Mr USA,Mr IAH,Mr Woodreau and all other highly learned aviation experts.

Having learnt about the ILS CAT IIIB and other categories and also about the weather and myriads of various other aspects of Low visibility operations and different factors that constitute a successful execution of this unique procedure with respect to the equipments on the ground,I am now curious about the system that is installed in the aircraft which makes the aircraft compatible with the airport that has the ILS CAT II/III.

I have already learnt that there are three pre requisites for a successful CAT IIIB operation and they are :-: AIRPORT, AIRPLANE and the TRAINED PILOTS.

I remember at the very beginning of this thread I came across a comment where someone had mentioned "All Modern aircrafts have this tech" or something similar to that and having done a little reading about this issue I figured that the aircraft needs to have the required tech to synchronize with the system on ground to be able to carry out a successful Low Visibility Operation and I also learnt that not all aircrafts have this system...I mean may be I'm reading an older article and now all the aircrafts are pre installed with CAT III system before being delivered but here are my questions regarding the Aircraft aspect of it all -:

1. Is the autolanding system,and all the other systems in relation to Low visibility conditions, pre installed or the airlines have to pay extra and get their aircrafts equip with it ?

2. If the Aircraft is equipped with Low Visibility system then are there different systems for different Categories ? or for instance if an Aircraft has the best category of all i.e CAT IIIB then that system takes care of it all ?

3.What is the price difference should an airline get its aircraft equipped with such tech with the original price of an aircraft ?

Thanks again !


1. A Fail Operational ILS autoland system should be pretty standard nowadays on larger airliners. However, something like GLS autoland would be an option.

Importantly, having the system is nowhere near enough. You also need to have the requisite procedures and maintain crew proficiency. So even if the plane can autoland, an operator might not be authorised for it.

2. The aircraft doesn't know the conditions. If it can do a fail operational autoland, that's all you need.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
GalaxyFlyer
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Re: The Magic of "CAT IIIB"

Thu Feb 18, 2021 12:29 am

The price on any aircraft purchase is a slippery concept, closely guarded, lots of deals thrown in plus financial performance guarantees or penalties.
 
FligtReporter
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Re: The Magic of "CAT IIIB"

Thu Feb 18, 2021 1:26 am

Thanks Mr Starlion and Mr Galaxy !
 
BoeingGuy
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Re: The Magic of "CAT IIIB"

Thu Feb 18, 2021 3:32 am

CanukinUSA wrote:
Correction: There is not a useable back course signal emitted from most ILS localizers anymore. In order to cut down on signal reflections and bends most of the new ILS do not transmit a usable signal in the opposite direction for the back course approach anymore.
At many airports there is now only one transmitter used with two antennas at opposite ends of the runway on the same frequency. The controller switches antennas to use the ILS approach for the runway that is in use only.


To my knowledge there are very few Backcourse ILSs in the US. In the west, I only know of a few: SNA, YKM, IDA, and SLE, AFAIK. Boeing test flights often go to IDA when they need to test Backcourse capability.
 
GalaxyFlyer
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Re: The Magic of "CAT IIIB"

Thu Feb 18, 2021 2:50 pm

Yes, it’s going away, I haven’t flown one on a PC check in a long time. Never saw one in the military
 
Tristarsteve
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Re: The Magic of "CAT IIIB"

Thu Feb 18, 2021 3:39 pm

In 2009 British Airways started using the Microwave Landing System (MLS) at LHR. The Ils/Gps receivers were modified with an MLS card. and most of the narrow body Airbus were so equipped. The system worked exactly the same as the ILS as far as the crews were aware.
But as the BA A320 fleet was responsible for nearly 40 pc of LHR approaches, agreement was made with the airport that the BA A320s would be sequenced in a row on the approach. The MLS was not affected by close spaced aircraft like an ILS. So BA won as their A320s were taken out of the stack and sent for approach before other ILS equipped aircraft.
Is this still working? Did anyone else use MLS?

LHR has been Cat 3B for a long time. I remember boarding a BEA Trident3B in 1972 at LHR on a very foggy evening. We taxyed out to the holding point, waiting for 75m RVR to allow us to take off. Two hours later we arrived back on the stand and got off.
 
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Re: The Magic of "CAT IIIB"

Thu Feb 18, 2021 4:58 pm

Tristarsteve wrote:
In 2009 British Airways started using the Microwave Landing System (MLS) at LHR. The Ils/Gps receivers were modified with an MLS card. and most of the narrow body Airbus were so equipped. The system worked exactly the same as the ILS as far as the crews were aware.
But as the BA A320 fleet was responsible for nearly 40 pc of LHR approaches, agreement was made with the airport that the BA A320s would be sequenced in a row on the approach. The MLS was not affected by close spaced aircraft like an ILS. So BA won as their A320s were taken out of the stack and sent for approach before other ILS equipped aircraft.
Is this still working? Did anyone else use MLS?

LHR has been Cat 3B for a long time. I remember boarding a BEA Trident3B in 1972 at LHR on a very foggy evening. We taxyed out to the holding point, waiting for 75m RVR to allow us to take off. Two hours later we arrived back on the stand and got off.


1972...Daymn...thats like 20 something years before I was born it means CAT IIIB has been there for quite some time now.
 
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Starlionblue
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Re: The Magic of "CAT IIIB"

Thu Feb 18, 2021 11:14 pm

FligtReporter wrote:
Tristarsteve wrote:
In 2009 British Airways started using the Microwave Landing System (MLS) at LHR. The Ils/Gps receivers were modified with an MLS card. and most of the narrow body Airbus were so equipped. The system worked exactly the same as the ILS as far as the crews were aware.
But as the BA A320 fleet was responsible for nearly 40 pc of LHR approaches, agreement was made with the airport that the BA A320s would be sequenced in a row on the approach. The MLS was not affected by close spaced aircraft like an ILS. So BA won as their A320s were taken out of the stack and sent for approach before other ILS equipped aircraft.
Is this still working? Did anyone else use MLS?

LHR has been Cat 3B for a long time. I remember boarding a BEA Trident3B in 1972 at LHR on a very foggy evening. We taxyed out to the holding point, waiting for 75m RVR to allow us to take off. Two hours later we arrived back on the stand and got off.


1972...Daymn...thats like 20 something years before I was born it means CAT IIIB has been there for quite some time now.


The first autoland with passengers on board was in 1965.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
e38
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Re: The Magic of "CAT IIIB"

Fri Feb 19, 2021 2:28 am

Starlionblue wrote:
The first autoland with passengers on board was in 1965.


Yes!

10 June 1965.
British European Airways - BEA
Flight BE343 at London Heathrow Airport
routing was Paris Le Bourget Airport - London Heathrow Airport
Hawker Siddeley HS 121 Trident 1C G-ARPR

(sources: wikipedia-BEA and rzjets.net)

e38
 
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Re: The Magic of "CAT IIIB"

Fri Feb 19, 2021 3:08 am

Starlionblue wrote:
FligtReporter wrote:
Tristarsteve wrote:
In 2009 British Airways started using the Microwave Landing System (MLS) at LHR. The Ils/Gps receivers were modified with an MLS card. and most of the narrow body Airbus were so equipped. The system worked exactly the same as the ILS as far as the crews were aware.
But as the BA A320 fleet was responsible for nearly 40 pc of LHR approaches, agreement was made with the airport that the BA A320s would be sequenced in a row on the approach. The MLS was not affected by close spaced aircraft like an ILS. So BA won as their A320s were taken out of the stack and sent for approach before other ILS equipped aircraft.
Is this still working? Did anyone else use MLS?

LHR has been Cat 3B for a long time. I remember boarding a BEA Trident3B in 1972 at LHR on a very foggy evening. We taxyed out to the holding point, waiting for 75m RVR to allow us to take off. Two hours later we arrived back on the stand and got off.


1972...Daymn...thats like 20 something years before I was born it means CAT IIIB has been there for quite some time now.


The first autoland with passengers on board was in 1965.


Oh...I wonder why did KLM not get their demonic pilot Vanzanten trained with Low Visibility Ops...The only words I will forever remember him by, are that of Cap Grubbs' which were recorded moments before the collision.

But honestly,I believe even had the KLM gotten that man equipped with required training it wouldn't have prevented what happened,for it was more of his vile egoistic self that murdered so many innocent people.
Last edited by FligtReporter on Fri Feb 19, 2021 3:31 am, edited 3 times in total.
 
FligtReporter
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Re: The Magic of "CAT IIIB"

Fri Feb 19, 2021 3:10 am

e38 wrote:
Starlionblue wrote:
The first autoland with passengers on board was in 1965.


Yes!

10 June 1965.
British European Airways - BEA
Flight BE343 at London Heathrow Airport
routing was Paris Le Bourget Airport - London Heathrow Airport
Hawker Siddeley HS 121 Trident 1C G-ARPR

(sources: wikipedia-BEA and rzjets.net)

e38


WooW you even remember the details of it Mr E38 !! Were you present at that time when this happened ?
 
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Starlionblue
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Re: The Magic of "CAT IIIB"

Fri Feb 19, 2021 3:48 am

FligtReporter wrote:
Starlionblue wrote:
FligtReporter wrote:

1972...Daymn...thats like 20 something years before I was born it means CAT IIIB has been there for quite some time now.


The first autoland with passengers on board was in 1965.


Oh...I wonder why did KLM not get their demonic pilot Vanzanten trained with Low Visibility Ops...The only words I will forever remember him by now are that of Cap Grubbs which were recorded moments before the collision.

But honestly,I believe even had the KLM gotten that man equipped with required training it wouldn't have prevented what happened,for it was more of his vile egoistic self that murdered so many innocent people.


Before judging any aircraft incident or accident, it is important to remember that no pilot goes to work intending to make a serious mistake. We go to work intending to have a normal day, as did Captain Van Zanten on that day. He was neither vile nor egotistic. He made an error, yes, but only a very unusual combination of circumstances made this error have horrific consequences.

He is held up as a poster child for bad CRM, but we have to judge his actions in the context of both the era and the situation. And as with almost all accidents, there is not one single causal factor. The holes in the Swiss cheese all have to line up. The absence of any one of a number of factors would have prevented the Teneriffe disaster.

This was back in the day when captains were still Sky Gods and there was a much sharper authority gradient in the cockpit. At the time, there was little CRM training in the way we think of it today. At the time, comms were not standardised like today. Low visibility training was not the same either.

The crew was under pressure as their duty time was about to expire. It took the combination of lack of CRM, time pressure, an unusually congested airport due to the destination being closed, low viz, and non-standardised communications, to create the situation. While Captain van Zanten was in error, he didn't make the error because of his lack of skills. Many documentaries tend to focus on his particular action and words as the focal point and the one "big thing" that caused the accident. In reality, his error would have been inconsequential if not for that combination of factors.

We have learned from many accidents, notably Teneriffe, NW255, and BEA548, that even highly skilled people make mistakes under stress that they would probably not make otherwise. The major change since then has been changing procedures, comms and operations to mitigate, catch and correct errors. Instead of assuming that humans can be trained to perform actions without error, there are various mechanisms in place to ensure errors don't have serious consequences. For example, checklists have been reformatted, CRM training has emphasized that FOs should speak up, accurate ATC readbacks are required, and so on.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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Re: The Magic of "CAT IIIB"

Fri Feb 19, 2021 4:17 am

Starlionblue wrote:
FligtReporter wrote:
Starlionblue wrote:

The first autoland with passengers on board was in 1965.


Oh...I wonder why did KLM not get their demonic pilot Vanzanten trained with Low Visibility Ops...The only words I will forever remember him by now are that of Cap Grubbs which were recorded moments before the collision.

But honestly,I believe even had the KLM gotten that man equipped with required training it wouldn't have prevented what happened,for it was more of his vile egoistic self that murdered so many innocent people.


Before judging any aircraft incident or accident, it is important to remember that no pilot goes to work intending to make a serious mistake. We go to work intending to have a normal day, as did Captain Van Zanten on that day. He was neither vile nor egotistic. He made an error, yes, but only a very unusual combination of circumstances made this error have horrific consequences.

He is held up as a poster child for bad CRM, but we have to judge his actions in the context of both the era and the situation. And as with almost all accidents, there is not one single causal factor. The holes in the Swiss cheese all have to line up. The absence of any one of a number of factors would have prevented the Teneriffe disaster.

This was back in the day when captains were still Sky Gods and there was a much sharper authority gradient in the cockpit. At the time, there was little CRM training in the way we think of it today. At the time, comms were not standardised like today. Low visibility training was not the same either.

The crew was under pressure as their duty time was about to expire. It took the combination of lack of CRM, time pressure, an unusually congested airport due to the destination being closed, low viz, and non-standardised communications, to create the situation. While Captain van Zanten was in error, he didn't make the error because of his lack of skills. Many documentaries tend to focus on his particular action and words as the focal point and the one "big thing" that caused the accident. In reality, his error would have been inconsequential if not for that combination of factors.

We have learned from many accidents, notably Teneriffe, NW255, and BEA548, that even highly skilled people make mistakes under stress that they would probably not make otherwise. The major change since then has been changing procedures, comms and operations to mitigate, catch and correct errors. Instead of assuming that humans can be trained to perform actions without error, there are various mechanisms in place to ensure errors don't have serious consequences. For example, checklists have been reformatted, CRM training has emphasized that FOs should speak up, accurate ATC readbacks are required, and so on.


I completely understand that pilots are humans and at the end of the day they have working hour limitations and various other pressures with relation to their jobs, however,the most critical part of their job is that it involves people's Iives and I'm sure no pilot would ever wanna be in a scenario where they become the cause for the loss of it.I know that there may be difficulty in understanding the ATC or their way of speaking to them,the detriorating visibility etc, however, for some obvious reasons I can't ignore that man's decision to takeoff when obviously there was uncertainty around it given the erratic significant visibility drop..So I believe it was HIS decision,fuled by arrogance,was the final nail in the coffin so many innocent people.

But its because of such disasters that flying is so much safer now.

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