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Murf
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Cat II /Cat III Questions

Fri Feb 09, 2007 11:07 am

Hey guys,

I have questions on Cat I/II/III I'm hoping someone could answer. This much I do know. There are different minimum height and visibility, the crew must be qualified, the aircraft must be certified and the airport must be certified.

What is different physically on say a 737 that is cat II certified and a 737 that is cat III certified? Or even a 737 that is Cat I.

Is there more or less of something?

Do the components have higher tolerences?

Does the Cat III plane have more autopilots?
 
N231YE
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 11:14 am

Quoting Murf (Thread starter):
Does the Cat III plane have more autopilots?

I am pretty sure that Cat III aircraft must have an autopilot that can land the aircraft.
 
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Zkpilot
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 11:29 am

Quoting N231YE (Reply 1):
I am pretty sure that Cat III aircraft must have an autopilot that can land the aircraft.

commonly refered to as autoland...
keeps the aircraft on centreline even on rollout.

Category I - A precision instrument approach and landing with a decision height not lower than 60 m (200 ft) above touchdown zone elevation and with either a visibility not less than 800 m or a runway visual range not less than 550 m.
Category II - Category II operation: A precision instrument approach and landing with a decision height lower than 60 m (200 ft) above touchdown zone elevation but not lower than 30 m (100 ft), and a runway visual range not less than 350 m.
Category III is further subdivided
Category III A - A precision instrument approach and landing with: a) a decision height lower than 30 m (100 ft) above touchdown zone elevation, or no decision height; and b) a runway visual range not less than 200 m.
Category III B - A precision instrument approach and landing with: a) a decision height lower than 15 m (50 ft) above touchdown zone elevation, or no decision height; and b) a runway visual range less than 200 m but not less than 50 m.
Category III C - A precision instrument approach and landing with no decision height and no runway visual range limitations. A Category III C system is capable of using an aircraft's autopilot to land and guide the aircraft to the terminal if required.
In each case a suitably equipped aircraft and appropriately qualified crew are required. For example, Cat IIIc requires three autopilots, Cat I does not. Cat I only goes off of altimeter indications for decision height, the Cat II and Cat III approaches go off the radar altimeter for a decision height

(Reference ICAO Annex 10 AERONAUTICAL TELECOMMUNICATIONS Volume 1 RADIO NAVIGATION AIDS 2.1.1)
64 types. 45 countries. 24 airlines.
 
N231YE
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 11:36 am

Quoting Zkpilot (Reply 2):

Thanks for the clarification.
 
3DPlanes
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 12:45 pm

Quoting Zkpilot (Reply 2):
land and guide the aircraft to the terminal if required.

Out of curiosity, how do they do the latter? I mean the runway has an ILS beam down the center, so I get that... What do the taxiways have?
"Simplicate and add lightness." - Ed Heinemann
 
411A
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 1:39 pm

CATIIIC was available at one time at LHR, for HS.121 aircraft, including runway turnoff guideance.
Not anymore.
Too expensive.

Generally speaking, automatic approach/land (autoland) equipment is required for CATIII operations.
However, runway guideance is not necessarily available on some types.
Example.
B737-800 aircraft.
The autopilot(s) disconnect at touchdown, leaving the pilot to keep to the runway centerline.

L1011?
Yes, the autopilots remain engaged thruout the rollout maneuver, precisely on the runway (localizer) centerline.
Disengage to taxi to the parking stand.

A far superior design.
And, why not....it's a Lockheed.
 
2H4
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 2:04 pm




Quoting 411A (Reply 5):
Example.
B737-800 aircraft.
The autopilot(s) disconnect at touchdown, leaving the pilot to keep to the runway centerline.

Why, in your opinion, did Boeing opt to go with this option over the latter?


2H4


Intentionally Left Blank
 
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zeke
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 3:12 pm

Quoting Murf (Thread starter):

Is there more or less of something?

As far as I understand the older 732s were Cat 2, and the 732-ADV, and the newer 737s cat 3a.

Quoting Zkpilot (Reply 2):

(Reference ICAO Annex 10 AERONAUTICAL TELECOMMUNICATIONS Volume 1
RADIO NAVIGATION AIDS 2.1.1)

Whilst I know that is word for word what wiki says, that is not correct for para 2.1.1, I have the actual document.

What para 2.1.1 actually says :
"2.1.1 The standard non-visual aids to precision approach and landing shall be:
a) the instrument landing system (ILS) conforming to the Standards contained in Chapter 3,3.1;
b) the microwave landing system (MLS) conforming to the Standards contained in Chapter 3, 3.11; and
c) the global navigation satellite system (GNSS) conforming to the Standards contained in Chapter 3, 3.7."

Para 3.1.1 Definitions says

"Facility Performance Category I - ILS. An ILS which provides guidance information from the coverage limit of the ILS to the point at which the localizer course line intersects the ILS glide path at a height of 60 m (200 ft) or less above the horizontal plane containing the threshold.

Facility Performance Category II - ILS. An ILS which provides guidance information from the coverage limit of the ILS to the point at which the localizer course line intersects the ILS glide path at a height of 15 m (50 ft) or less above the horizontal plane containing the threshold.

Facility Performance Category III - ILS. An ILS which, with the aid of ancillary equipment where necessary, provides guidance information from the coverage limit of the facility to, and along, the surface of the runway."

Quoting 2H4 (Reply 6):
Why, in your opinion, did Boeing opt to go with this option over the latter?

Just a limit as far as I know with the 737 autopilot, not being able to track the runway whilst on the ground with the autopilot (something to do with the rudder control with the autopilot), hence Cat 3a.
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PhilSquares
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 3:49 pm

Quoting 411A (Reply 5):
L1011?
Yes, the autopilots remain engaged thruout the rollout maneuver, precisely on the runway (localizer) centerline.
Disengage to taxi to the parking stand

747/744 will do the exact same thing.....
Fly fast, live slow
 
Tristarsteve
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 4:48 pm

Quoting Zeke (Reply 7):
Just a limit as far as I know with the 737 autopilot, not being able to track the runway whilst on the ground with the autopilot (something to do with the rudder control with the autopilot), hence Cat 3a.

The B737 does not have a rudder servo that the autopilot can control, so it has no means of steering the aircraft on the runway.

Quoting 2H4 (Reply 6):
Why, in your opinion, did Boeing opt to go with this option over the

The B737 has never had a rudder channel in the autopilot, so I suppose Boeing decided that it had worked well for 30 years so why change it. The rudder channel is only used during the landing to kick off drift and steer down the runway. It is a lot of equipment for little gain, unless your main base is below Cat3a limits regularly, when it is a good selling point for the A320.
 
Valcory
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 5:15 pm

Quoting 411A (Reply 5):
L1011?
Yes, the autopilots remain engaged thruout the rollout maneuver, precisely on the runway (localizer) centerline.
Disengage to taxi to the parking stand.

That option is available for the 737 NG

The 737 NG can only be CATIII A (you can downgrade it to Cat II or CATI) I think 3 autopilots are reguire for CATIII 3 B The 737 NG has only two autopilots besides 3 autopilot you are going to need three electrical sources(independent) on the 757/767 the center bus is isolated and used as a third electircal source for the center autopilot.(Basicly the center bus is power by the standy electrical system rather than the left main bus) Yeah a little off topic but i am bored. At 1500 ft you are suppose to get a cat satus
 
AAR90
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 6:26 pm

Quoting N231YE (Reply 1):
I am pretty sure that Cat III aircraft must have an autopilot that can land the aircraft.

Or a certified HUD system.  Wink
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
Tristarsteve
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 6:37 pm

Quoting Valcory (Reply 10):
That option is available for the 737 NG

The 737 NG can only be CATIII A (you can downgrade it to Cat II or CATI) I think 3 autopilots are reguire for CATIII 3 B The 737 NG has only two autopilots

I only worked on B737 -2/3/4/500.
But I was reading a Fam manual for the NG and there was no mention of a rudder channel in the autopilot. Is this something that came later?

The Tristar was Cat 3B with two autopilots, but they had extensive fail monitoring built in so it was fail operational.

The problem with B737 is that is an old design that has been upgraded. There are only two aileron actuators and two elevator actuators. This limits the A/P capability. The B737 is two channel A/P fail passive so it could never be Cat3B. (as said before unlike the HS Trident of 1966 which was Cat 3C, had three A/Ps and three actuators on each surface and three main hyd systems.!)

Very interested to know how Boeing got roll out guidance into the B737NG.
 
QXatFAT
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 8:12 pm

Quoting Zkpilot (Reply 2):
Category III C - A precision instrument approach and landing with no decision height and no runway visual range limitations. A Category III C system is capable of using an aircraft's autopilot to land and guide the aircraft to the terminal if required.

This is correct. I believe FAT is CAT III C. Correct me if I am wrong. I know that FAT is CAT III just dont know what class. When you are here during the Fall and Winter months when the fog is at its peak, with all the flights on the screens saying cancelled all the way across but here comes in the QX CRJ700 jet right on time and the only one that is not cancelled using the CAT III program. Quite amazing I might add.
Don't Tread On Me!
 
CosmicCruiser
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 9:25 pm

Quoting 411A (Reply 5):
Yes, the autopilots remain engaged thruout the rollout maneuver, precisely on the runway (localizer) centerline.
Disengage to taxi to the parking stand.

As does the MD-11 hence different RVR mins depending on whether the jet is A or B. I've heard a variety of definitions on this board and if everyone's post is correct there's a bunch of diff. definitions. For us CATIIIA is w/o rollout guidance and CATIIIB is w/ rollout guidance. In fact we don't use A or B now it's just W/ or W/O rollout. W/O rollout you MUST have some visual reference to land 'cause you'll need to see to steer after touchdown thus mins are 600'(175m). W/ rollout no visual reference is required and the jet will steer the centerline to a full stop if you wish, mins are 300'. Both app have a 100' AH.Of the CATIII jets I've flown both had dual A/P and of course they are 3 axis'.
 
vikkyvik
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RE: Cat II /Cat III Questions

Fri Feb 09, 2007 11:33 pm

Quoting QXatFAT (Reply 13):
This is correct. I believe FAT is CAT III C. Correct me if I am wrong.

You're wrong  Wink

Airnav lists FAT as CatIIIB. No surprise there, as most major airports in the US go up to IIIB. Don't think I've ever seen one listed as IIIC.

Quoting TristarSteve (Reply 9):
The B737 has never had a rudder channel in the autopilot, so I suppose Boeing decided that it had worked well for 30 years so why change it. The rudder channel is only used during the landing to kick off drift and steer down the runway. It is a lot of equipment for little gain, unless your main base is below Cat3a limits regularly, when it is a good selling point for the A320.

I don't quite understand - if there's no rudder channel, how does the autopilot utilize the rudder during the approach?

Quoting AAR90 (Reply 11):
Or a certified HUD system.

That must be something else - handflying the aircraft down to the runway without seeing it until the last moment.  Smile
I'm watching Jeopardy. The category is worst Madonna songs. "This one from 1987 is terrible".
 
CosmicCruiser
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RE: Cat II /Cat III Questions

Sat Feb 10, 2007 4:46 am

Quoting Vikkyvik (Reply 15):
if there's no rudder channel, how does the autopilot utilize the rudder during the approach?

It doesn't. that's

Quoting Vikkyvik (Reply 15):
if there's no rudder channel, how does the autopilot utilize the rudder during the approach?

It doesn't. It's a 2 axis A/P.
On the MD-11 there are 2 A/P that work different elevators and are checking each other to agree on the signal received during the app. At 1500' (best I remember) the rudder goes to parallel to adjust for any x-wind. This is probably somewhat the same for any big jet. On every app the jet doesn't know CATI from CATIII. It just flies down the glideslope, does its tests and displays "dual land". It will go right down and land if you let or click it off and hand fly. During CATIII chks we most often fly an unprotected ILS that may or may not be a CATIII runway. Our only criteria is a minimum of 47' thsld x-ing hgt.
 
411A
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RE: Cat II /Cat III Questions

Sat Feb 10, 2007 8:03 am

L1011.

Was certified to CATIIIC capability, however, as no airport in the world now has this equipment installed, CATIIIB is the limit for operations, all other aircraft as well, that are CATIII capable.
The L10 also has two autopilots, however they are both dual channel.

B737-800 etc.

The reason that this airplane was not modernized at the time of design, is for one simple reason.
It would have required a new pilots type rating.
Southwest Airlines TOLD Boeing, another type rating, we don't purchase any more...period.
Info directly from a senior Boeing design engineer.
Money talks, make no mistake.

Several pilots who I have spoken with who have flown both the B737-800 and the L1011, tell me that the 'ole Lockheed design is the best there is, far better than the old Boeing autopilot design on the NG B737's.
 
Pihero
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RE: Cat II /Cat III Questions

Sun Feb 11, 2007 8:58 pm

Quoting 411A (Reply 17):
The L10 also has two autopilots, however they are both dual channel.



Quoting 411A (Reply 17):
the 'ole Lockheed design is the best there is, far better than the old Boeing autopilot design on the NG B737's.

And you have to add that these autopilots were the very best analogical technology could allow. Having flown the 1011 along with all kinds of 747 and 767 and Airbii (hello Starlion !), I have to say that the Lockheed's hardware was by far the smoothest and the most precise... Its only weakness compared to modern digital A/Ps was a rather heavy validation procedure - you needed a flight engineer to confirm you could use it for your next approach... Still remember the discussions about hard and soft DANAs* among the crews !
*DANA = "dual autoland not available", general purpose message meaning an impossibility to cat III.

411A,
Very interesting tip on the reason for the 738 obsolete A/P technology. Thanks
Contrail designer
 
Tristarsteve
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RE: Cat II /Cat III Questions

Sun Feb 11, 2007 9:47 pm

Quoting Pihero (Reply 18):
Its only weakness compared to modern digital A/Ps was a rather heavy validation procedure - you needed a flight engineer to confirm you could use it for your next approach.

When the L1011 was in the hangar for an Autoland problem, the avionics guys had this enormous test set in the cockpit and all the hydraulics on, for hours at a time trying to get the thing to work again. BITE was almost non existant then.
Engineers working on modern digital aircraft could not imagine the work involved to keep the Tristar serviceable. Nowadays on an A320 you just push a button on the MCDU and then it says Autoland Sat. Job done.
 
AAR90
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RE: Cat II /Cat III Questions

Mon Feb 12, 2007 4:24 am

Quoting Vikkyvik (Reply 15):
That must be something else - handflying the aircraft down to the runway without seeing it until the last moment.

Hmmmm.... never really thought about it. But then, I've landed aboard USS Enterprise three times and never saw a thing! And that was without a HUD, or ILS, or.... anything.  Wink
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
vikkyvik
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RE: Cat II /Cat III Questions

Mon Feb 12, 2007 6:54 am

Quoting AAR90 (Reply 20):

Hmmmm.... never really thought about it. But then, I've landed aboard USS Enterprise three times and never saw a thing! And that was without a HUD, or ILS, or.... anything.

Haha, well trust me, us non-pilots think about it quite often to say the least.....  Wink
I'm watching Jeopardy. The category is worst Madonna songs. "This one from 1987 is terrible".
 
Tristarsteve
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RE: Cat II /Cat III Questions

Mon Feb 12, 2007 5:10 pm

Cat 3B autoland systems must align the aircraft with the runway as it lands. In a crosswind the aircraft must be turned onto runway heading during the flare. I remember from Trident days it was called Kick off drift when the Rudder channel jumped into action at 50ft Radio and straightened the aircraft up. I assume that all Cat3B systems do something similar.
Now the B737 has no rudder channel. So my question is how does the autopilot line up the aircraft. Does it use the roll channel to do this, or does the pilot do it manually , or are the crosswind limits much lower so this is not a problem.
 
n685fe
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RE: Cat II /Cat III Questions

Tue Feb 13, 2007 12:18 am

Quoting CosmicCruiser (Reply 16):
On the MD-11 there are 2 A/P that work different elevators and are checking each other to agree on the signal received during the app. At 1500' (best I remember) the rudder goes to parallel to adjust for any x-wind. This is probably somewhat the same for any big jet. On every app the jet doesn't know CATI from CATIII. It just flies down the glideslope, does its tests and displays "dual land". It will go right down and land if you let or click it off and hand fly. During CATIII chks we most often fly an unprotected ILS that may or may not be a CATIII runway. Our only criteria is a minimum of 47' thsld x-ing hgt.



Quoting TristarSteve (Reply 22):
Cat 3B autoland systems must align the aircraft with the runway as it lands. In a crosswind the aircraft must be turned onto runway heading during the flare. I remember from Trident days it was called Kick off drift when the Rudder channel jumped into action at 50ft Radio and straightened the aircraft up. I assume that all Cat3B systems do something similar.

On the MD10 the align maneuver is initiated at 150 ft R/A, uses a fwd slip to decrease lateral drift due to crosswinds during crab. AFS uses the heading from the FMS to calculate the alignment error. During touchdown the error is decreaed to less then three dergrees and the nose is aligned into the crosswind. B< is limited to 6 degrees, the crab angle is reduced through rudder commands. The alignment maneuver produces an alignment error of less than 20% of the original error at 150' R/A and ends at the begining of rollout. The A/P controls the yaw so the a/c stays on the centerline. As speed reduces, the nosewheel becomes effective and maintains the a/c on the localizer centerline.
Each FCC has pitch roll and yaw software that has two channels each, during a CAT III on the MD the A/P's utilize all channels to control the following:
RT O/B=1A, LT I/B=1B, LT O/B=2A, RT I/B=2B elevators
LT I/B=1A, RT O/B=1B, RT I/B=2A, LT O/B=2B ailerons
Lower rudder=1A & 1B
Upper rudder=2A & 2B



.
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troubleshooter
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RE: Cat II /Cat III Questions

Tue Feb 13, 2007 5:11 am

Quoting TristarSteve (Reply 12):
The B737 is two channel A/P fail passive so it could never be Cat3B.



Quoting Valcory (Reply 10):
The 737 NG can only be CATIII A (you can downgrade it to Cat II or CATI)

Not fully correct. The B737NG has a dual two channel autopilot system (dual fail-safe) wich allows for CAT IIIA operation. BUT Rockwell Collins sells an enhanced system EDFCS-730 which allows up to CAT IIIB operation. An upgraded FCC, MCP and a rudder servo are part of the new system which is available since 2003.
This job sucks!!! I love this job!!!
 
Valcory
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RE: Cat II /Cat III Questions

Tue Feb 13, 2007 8:52 am

[quote=Troubleshooter,reply=24]Quoting Valcory (Reply 10):
The 737 NG can only be CATIII A (you can downgrade it to Cat II or CATI)[/quot
Let me rephrase that the 737 NG i work on are CATIIIA
 
troubleshooter
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RE: Cat II /Cat III Questions

Tue Feb 13, 2007 9:11 pm

Quoting Valcory (Reply 25):
Let me rephrase that the 737 NG i work on are CATIIIA

All NG´s I work on are CAT IIIA, too. I just tried to point out that since 2003 the NG can be CAT IIIB if the enhanced system is installed. It is not correct to say the B737NG is generally limited to CAT IIIA. The enhanced system can be fitted to earlier models for upgrade them. Hope all is clear now.
This job sucks!!! I love this job!!!
 
chrisMUC
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RE: Cat II /Cat III Questions

Wed Feb 14, 2007 6:33 am

Quoting TristarSteve (Reply 22):
similar.
Now the B737 has no rudder channel. So my question is how does the autopilot line up the aircraft. Does it use the roll channel to do this, or does the pilot do it manually , or are the crosswind limits much lower so this is not a problem.

The X-wind limit for Cat IIIa landings on classic 737s (at least at my company) is 10 kts - so there is no need to take out the grab. Cat III visibility with more than 10 kts is very rare, because fog = no wind.
 
highflyer9790
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RE: Cat II /Cat III Questions

Wed Feb 14, 2007 6:51 am

i think DEN is CATIIIc approved
121
 
CosmicCruiser
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RE: Cat II /Cat III Questions

Wed Feb 14, 2007 8:14 am

Quoting HighFlyer9790 (Reply 28):
i think DEN is CATIIIc approved

I can't say that someone may not have a special auth. chart but our LIDO charts show all CATIII app. to DEN have a 300RVR min.
 
PhilSquares
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RE: Cat II /Cat III Questions

Wed Feb 14, 2007 10:07 am

Quoting HighFlyer9790 (Reply 28):
i think DEN is CATIIIc approved

There is no CAT IIIC at Denver.

Ref: http://www.airnav.com/airport/KDEN
Fly fast, live slow
 
Boeing7E7
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RE: Cat II /Cat III Questions

Wed Feb 14, 2007 5:00 pm

Airports do not differentiate between levels of CAT III capability (a/b/c). The variations on CAT III (a/b/c) have to do with the aircraft equipment and crew qualifications. The runway as a stand alone component qualifies for CAT I/II/III based on equipment, layout and obstacle analysis.

This TERPs order discusses obstacle risk analysis and airport system requirements for CAT II/III runway qualification:

http://www.faa.gov/about/office%5For...ce/orders/media/N8260-61_FINAL.pdf

Denver's CAT III chart. The minima are listed at the bottom of the plate as CAT IIIa, IIIb and IIIc.

http://204.108.4.16/d-tpp/0701/09077I34LC3.PDF
 
PhilSquares
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RE: Cat II /Cat III Questions

Wed Feb 14, 2007 5:55 pm

Quoting Boeing7E7 (Reply 31):
Denver's CAT III chart. The minima are listed at the bottom of the plate as CAT IIIa, IIIb and IIIc

That is very true. However, you will note the minimuma for the CAT IIIC is NA (not authorised)
Fly fast, live slow
 
Boeing7E7
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RE: Cat II /Cat III Questions

Wed Feb 14, 2007 7:27 pm

Quoting PhilSquares (Reply 32):
However, you will note the minimuma for the CAT IIIC is NA (not authorised)

CAT IIIc requires specific approvals and is not listed for general use. It has nothing to do with the runway, each operator/aircraft is given a specific RVR based on the proceedure certification process.
 
PhilSquares
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RE: Cat II /Cat III Questions

Wed Feb 14, 2007 7:49 pm

Quoting Boeing7E7 (Reply 33):
CAT IIIc requires specific approvals and is not listed for general use. It has nothing to do with the runway, each operator/aircraft is given a specific RVR based on the proceedure certification process.

Well, we may be talking about sematics here, but as far as I know there are no CAT IIIC approaches anyplace. And as such, that's why there is a NA (not authorised) on the approach plate. If a carrier were to have CAT IIIC authoisation, they still couldn't use KDEN since it's NA.

Your comments about the runway are not entirely correct. There are three things for LLM approval. 1) The approach(runway and terrain) 2) the aircraft 3) Crew certification.

If you look at KMSP, there's no CAT III for 30L/R and that' is due to the runway and the terrain on the approach end of the runway, while the other runways 12L/R do.
Fly fast, live slow
 
Boeing7E7
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RE: Cat II /Cat III Questions

Thu Feb 15, 2007 12:01 am

Quoting PhilSquares (Reply 34):
Your comments about the runway are not entirely correct. There are three things for LLM approval. 1) The approach(runway and terrain) 2) the aircraft 3) Crew certification.

Ref:

Quoting Boeing7E7 (Reply 31):
Airports do not differentiate between levels of CAT III capability (a/b/c). The variations on CAT III (a/b/c) have to do with the aircraft equipment and crew qualifications. The runway as a stand alone component qualifies for CAT I/II/III based on equipment, layout and obstacle analysis.



Quoting PhilSquares (Reply 34):
Well, we may be talking about sematics here, but as far as I know there are no CAT IIIC approaches anyplace. And as such, that's why there is a NA (not authorised) on the approach plate. If a carrier were to have CAT IIIC authoisation, they still couldn't use KDEN since it's NA.

Some foreign carriers have 250 RVR IIIc. Denver has a procedure as do several other major airports. Boeing (now owning Jepp) intends to have the 787 roll out with a IIIc ready nav-database and is developing procedures for use. The FAA intends to leave "NA" there for some time (AKA... FAA Sissy Factor).

[Edited 2007-02-14 16:02:44]
 
PhilSquares
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RE: Cat II /Cat III Questions

Thu Feb 15, 2007 12:30 am

Quoting Boeing7E7 (Reply 35):
Some foreign carriers have 250 RVR IIIc. Denver has a procedure as do several other major airports. Boeing (now owning Jepp) intends to have the 787 roll out with a IIIc ready nav-database and is developing procedures for use. The FAA intends to leave "NA" there for some time (AKA... FAA Sissy Factor).

That's great Boeing intends that. But, how do you get "to the gate" guidance? There is no facility that has CAT IIIc capability. Jepp also has NA on their plates and has airline specific minimua for CAT IIIa/b.
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Boeing7E7
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RE: Cat II /Cat III Questions

Thu Feb 15, 2007 1:45 am

Quoting PhilSquares (Reply 36):
That's great Boeing intends that. But, how do you get "to the gate" guidance?

That's the catch. That requires LAAS. Yet another problem. There was a study by Standford or MIT a few years ago that LAAS woudn't give the sought after accuracy, so far it doesn't. They took a look at MLS augmentation of the planned WAAS signal where WAAS would provide the enroute component, but MLS would provide the landing component - this before SA was removed improving lateral accuracy. The FAA has placed LAAS on the backburner, but technology may eclipse it. Using an MLS capable MMR (about the same cost as a LAAS receiver for the aircraft) WAAS could now be used as the lateral component and the Elevevation and P/DME functions of MLS could be used for the vertical component and distance correction and still allow complex approaches because it's a digital signal. Couple this with a FLIR equipped HUD and you virtually elininate the need for LAAS. MLS is a mature system and LAAS was only intended for major airports and it has all sorts of problems, another barrier when you consider system development cost. Europe (at least the UK) is now on the MLS bandwagon. The argument made in the research boiled down to this: Billions were spent on MLS development, it's mature, and it was never used commercially the way it was intended. Now they want to spend billions on LAAS and its not living up to expectations. Junk it, and go with a hybrid system with lateral WAAS to CAT I and use P/DME correction and add the vertical MLS component for airports with CAT II or III requirements. CAT III(a/b/c) would then be based on aircraft equipment, such as the HUD capability.

Quoting PhilSquares (Reply 36):
There is no facility that has CAT IIIc capability. Jepp also has NA on their plates and has airline specific minimua for CAT IIIa/b.

CAT IIIc is not facility dependent, it's aircraft equipment and crew dependent. The runway is either CAT III capable or it is not, all three (CAT IIIa/b/c) require the same obstruction analysis and airfield equipment. The FAA used to post the TERPS order for it on the public site, but they are incorporating it into the 8260. As for charts, Jepp won't publish the chart unless you're the carrier with approval for use. The general public does not have access to airline specific IIIc proceedures, but they will have access to standard IIIc minima when the FAA gets their heads out of the sand on the issue.

[Edited 2007-02-14 18:07:11]
 
Boeing7E7
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RE: Cat II /Cat III Questions

Thu Feb 15, 2007 2:35 am

Here's a link to a slick FLIR (EVS) video:

http://www.gulfstream.com/product_enhancement/evs/

The Aspen/Teton video is one thing, the low visibility is something else altogether.

[Edited 2007-02-14 18:41:00]
 
User avatar
zeke
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RE: Cat II /Cat III Questions

Fri Feb 16, 2007 3:39 am

Quoting Boeing7E7 (Reply 33):
It has nothing to do with the runway, each operator/aircraft is given a specific RVR based on the proceedure certification process.

IIIC is zero RVR restriction, placing an RVR on IIIc is saying its not IIIc. Airport lighting types does change the category of approach. IIIc does exist under ICAO & FAA, however as Phil says it is not approved, IIIc does not exist under JAR at all.

Saying "It has nothing to do with the runway" is also incorrect, e.g. the RVR transmissometers requirement is different for Cat IIIa to Cat IIIb, for IIIb 3 RVR transmissometers are required and they should read in 25 meter increments or less for landing minima below 175 meters, you may have just 2 RVR transmissometers for IIIa.

Quoting PhilSquares (Reply 34):
There are three things for LLM approval. 1) The approach(runway and terrain) 2) the aircraft 3) Crew certification.

One more Phil, the operator.

Quoting Boeing7E7 (Reply 37):
CAT IIIc is not facility dependent, it's aircraft equipment and crew dependent. The runway is either CAT III capable or it is not, all three (CAT IIIa/b/c) require the same obstruction analysis and airfield equipment.

How would you describe the 4R chart at JFK then ? http://204.108.4.16/d-tpp/0702/00610I4RC3.PDF

How would you describe 08L and 26R at YVR or 05 and 06L at YYZ being Cat 3a only ?
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PhilSquares
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RE: Cat II /Cat III Questions

Fri Feb 16, 2007 3:56 am

Quoting Zeke (Reply 39):
Quoting PhilSquares (Reply 34):
There are three things for LLM approval. 1) The approach(runway and terrain) 2) the aircraft 3) Crew certification.

One more Phil, the operator.

True. Again, semantics being such, the Crew Certification was inclusive of the Ops Specs (operator)
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Boeing7E7
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RE: Cat II /Cat III Questions

Fri Feb 16, 2007 4:19 pm

Quoting Zeke (Reply 39):
Saying "It has nothing to do with the runway" is also incorrect, e.g. the RVR transmissometers requirement is different for Cat IIIa to Cat IIIb, for IIIb 3 RVR transmissometers are required and they should read in 25 meter increments or less for landing minima below 175 meters, you may have just 2 RVR transmissometers for IIIa.

All CAT III runways require the same RVR equipment, the same lighting equipment, the same backup equipment, the same NAVAIDs and the same TERPs evaluation to enable CAT III operations, regardless the degree. Again, it has nothing to do with the runway. It is either a CAT III runway, or it is not. When you state...

"the RVR transmissometers requirement is different for Cat IIIa to Cat IIIb, for IIIb 3 RVR transmissometers are required and they should read in 25 meter increments or less for landing minima below 175 meters, you may have just 2 RVR transmissometers for IIIa."

...you are refering to a condition (or status if you prefer) of the airfield equipment in order to perform the approach. It's the equivalent to an ILS runway losing its glideslope component then having alternate minima applied until the glideslope is available again. In this instance, you're refering to a condition of CAT III RVR equipment and it's required status to achieve varying degrees of CAT III capability, not a runway design standard where varying types of equipment would be installed to enable varrying levels of CAT III operation. It's just not cost effective.

Quoting Zeke (Reply 39):
How would you describe the 4R chart at JFK then ?

Two possibles:

1. If a component is out of service/tolerance and planned to remain out of service for an extended period of time it is then removed from the approach plate. Much like a long term NOTAM is removed from the NOTAM listing and placed in the AFD.

2. More likey, no one has a need for the proceedure and thuse one has not been developed.

Have no comment on Canada, they have their own way of doing things. There are many airports out there that only list CAT I minimums. That doesn’t mean they don’t qualify for CAT II operations, it simply means there isn’t a need for a CAT II procedure even thought the airport has the equipment in place to support it.

Quoting PhilSquares (Reply 40):
True. Again, semantics being such, the Crew Certification was inclusive of the Ops Specs (operator)

It's not a semantics issue. You are discussing the issue from aircraft operator perspective and what the status of the runway equipment must be to enable CAT III levels. I'm discussing it from a airport equipment requirement and proceedure desing perspective for the runway to even qualify for CAT III use in any category, be it a,b or c.

Airport design standards are inclusive for accomodation, operator requirements are conditional based on system component availability and tolerance levels.

Quoting Zeke (Reply 39):
IIIC is zero RVR restriction, placing an RVR on IIIc is saying its not IIIc.

CAT III with an RVR of 250 is a modified CAT IIIc minima approved for certain carriers. Yes, the standard CAT IIIc is 0-0 just as the standard CAT I is 200 and 1/2. When you discuss DH and RVR minima from a design perspective, they simply serve as the lowest minmum for the runway. IIIb is an RVR down to 700, thus if the RVR is down to 250, then the next lowest minima category must apply (IIIc) with an altered RVR and/or DH. Therefore, an approach with an RVR for 250 is a CAT IIIc approach with an increase in the RVR level. When the FAA say they don't approve CAT IIIc they are "technically correct" (semantics) because they don't approve 0-0, but the reality is that they are in fact approving a CAT IIIc approach with an increased RVR level. As such, CAT IIIc proceedures do exist.

[Edited 2007-02-16 08:42:40]
 
PhilSquares
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RE: Cat II /Cat III Questions

Fri Feb 16, 2007 5:05 pm

Quoting Boeing7E7 (Reply 41):
As such, CAT IIIc proceedures do exist.

Again semantics. From an operators perspective there is no IIIc approach. CURRENTLY, there is no way to get from the runway to the gate. That's the crux of the problem. I realise the 787 will be CATIIIc, but the capability does not exist now or in the forseeable future.

Please keep in mind, what the FAA does and ICAO does are not always the same (circling approaches for example). I grew up in the FAA system and to be honest, I prefer the ICAO way of doing things.
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Boeing7E7
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RE: Cat II /Cat III Questions

Fri Feb 16, 2007 5:14 pm

Quoting PhilSquares (Reply 42):
From an operators perspective there is no IIIc approach.

The operators perspective is not the only perspective that counts. That is the crux of the problem. Many of the problems with integrating new technology is the operators extensive lobbying. Ironically, they are the first to bitch about delay issues. Its a complete load of crap and to be honest, I'm sick of hearing it from them. They are the greatest barrier to effiency and technology advancement.

Quoting PhilSquares (Reply 42):
the capability does not exist now or in the forseeable future

Sooner than you think.

Quoting PhilSquares (Reply 42):
I grew up in the FAA system and to be honest, I prefer the ICAO way of doing things.

This is where we part ways. The FAA isn't any great shakes, but ICAO is a joke.

[Edited 2007-02-16 09:25:46]
 
User avatar
zeke
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RE: Cat II /Cat III Questions

Fri Feb 16, 2007 8:00 pm

Quoting Boeing7E7 (Reply 41):
...you are refering to a condition (or status if you prefer) of the airfield equipment in order to perform the approach.

No I am not, please refer to FAA AC 120-28C which states my exact point above.

Quoting Boeing7E7 (Reply 41):
1. If a component is out of service/tolerance and planned to remain out of service for an extended period of time it is then removed from the approach plate. Much like a long term NOTAM is removed from the NOTAM listing and placed in the AFD.

2. More likey, no one has a need for the proceedure and thuse one has not been developed.

Sounds like BS to me, you should look at the other charts for the same airport which are also Cat 3.

Quoting Boeing7E7 (Reply 41):
Have no comment on Canada, they have their own way of doing things.

Just standard ICAO, the Cat 3 runway is just Cat 3a.

Quoting Boeing7E7 (Reply 41):
There are many airports out there that only list CAT I minimums. That doesn't mean they don't qualify for CAT II operations, it simply means there isn't a need for a CAT II procedure even thought the airport has the equipment in place to support it.

SYD for example has the need and equipment for Cat 2, they do not have the fast switch over backup power for the equipment so they can only publish Cat I.
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IAHFLYR
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RE: Cat II /Cat III Questions

Fri Feb 16, 2007 10:14 pm

Quoting Zeke (Reply 44):
SYD for example has the need and equipment for Cat 2, they do not have the fast switch over backup power for the equipment so they can only publish Cat I.

MMMM since they don't have the fast switch over backup power for the equipment, how is it then you can say they have all the equipment? That sounds very close to how some governmental agencies operate in the U.S.  banghead 
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David L
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RE: Cat II /Cat III Questions

Fri Feb 16, 2007 10:37 pm

Quoting IAHFLYR (Reply 45):
since they don't have the fast switch over backup power for the equipment, how is it then you can say they have all the equipment?

Semantics again?  Smile I took Zeke's post to mean SYD has all the CAT II equipment except the fast switch over backup power.
 
CosmicCruiser
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RE: Cat II /Cat III Questions

Fri Feb 16, 2007 11:08 pm

Quoting Boeing7E7 (Reply 41):
IIIb is an RVR down to 700,

As I posted earlier there seems to be a few diff definitions people give to this A/B thing. For us A is w/o rollout, B is with r/o and therefore afforded lower mins. As far as those mins go your post is in error 'cause we can go to 300'rvr with a CATIIIB app.

Quoting Zeke (Reply 44):
Just standard ICAO, the Cat 3 runway is just Cat 3a.

???? Checking my LIDO charts which are ICAO std some arpts differentiate between A & B and some don't. They publish 2 minimums, which for us, means either A or B anyway. If you use 600'rvr(this can be either A or B) then the RVRs are as such, tdz controlling, mid controlling and rollout required but advisory only. Meaning you COULD land with 600, 600,0. Now with the lower mins 300'rvr(B and fail operational) then all the rvrs are controlling so the lowest you can see would be 300,300,300. eg. see STN they do pub A & B (in meters) for us A is 200m; while B is 175m(r/o rvr adv only) and 75m R/O rvr controlling.

I checked my old Jepps and Lido and DEN did not show any CATIIIC mins and did not seperate A & B it just showed 600' and 300' with the already mentioned rvr diff.Man! now I'm getting confused!  confused 
 
Boeing7E7
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RE: Cat II /Cat III Questions

Fri Feb 16, 2007 11:42 pm

Quoting Zeke (Reply 44):
No I am not, please refer to FAA AC 120-28C which states my exact point above.

AC120-28C has nothing to do with Airport Design Standards. AC 120-28C applies to operator standards. Equipment requirements to certify the runway are in the TERPs orders (a required component), not an "advisory" circular and they do not differntiate between the types of CAT III approaches.

Quoting Zeke (Reply 44):
Sounds like BS to me, you should look at the other charts for the same airport which are also Cat 3.

Same issue as the previous example.

Quoting Zeke (Reply 44):
SYD for example has the need and equipment for Cat 2, they do not have the fast switch over backup power for the equipment so they can only publish Cat I.

Again, that is a result of the "condition" of the equipment not the capability of the runway.

Quoting CosmicCruiser (Reply 47):
As far as those mins go your post is in error 'cause we can go to 300'rvr with a CATIIIB app.

That's an "operator" approval, not a "facility" approval.

It works like this:

An airport operator designs and builds a runway and installs a system of components to accomodate CAT III operations - this is all an airport is concerned with in regard to CAT III operations. The FAA will then publish a proceedure if such a proceedure has demand, or a carrier can have an unpublished proceeudre developed specifically for them (Alaska Airlines does a lot of this in Alaska so they can operate at better minimums then those published - IAHFLYER can probably comment on how CO has a few RNP .15 or .11 proceedures in conjunction with LAAS testing that are not available to other carriers ). There aren't varying component lists to accomodate the varying degrees of CAT III proceedures. It's an all or nothing situation. An aircraft operator then seeks approval to operate in CAT III conditions at that facility, or to that runway end. If a component is out of service, then the carriers operation approval is limited due to the equipment outage.

[Edited 2007-02-16 15:48:25]
 
IAHFLYR
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RE: Cat II /Cat III Questions

Sat Feb 17, 2007 12:29 am

Quoting Boeing7E7 (Reply 48):
IAHFLYER can probably comment on how CO has a few RNP .15

Do you mean flyer or me...iahflyr??? I am already confused by the other one! hahaha
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