Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
CatIII A, B, And C  
User currently offlineGigneil From United States of America, joined Nov 2002, 16347 posts, RR: 84
Posted (10 years 9 months 2 weeks 3 days 5 hours ago) and read 1673 times:

I'm not as smart as some... can someone concisely detail the differences in the 3 Category III classifications?

All this talk of fog in Delhi has got me thinking... is it possible to build a truly all-weather airport?

N

8 replies: All unread, jump to last
 
User currently offlineZak From Greenland, joined Sep 2003, 1993 posts, RR: 8
Reply 1, posted (10 years 9 months 2 weeks 3 days 5 hours ago) and read 1650 times:

CATIIIc is 0/0 vis. the others have a slightly higher vis limit, i dont recall the exact nubmers but they were posted here a while ago.


10=2
User currently offlineGigneil From United States of America, joined Nov 2002, 16347 posts, RR: 84
Reply 2, posted (10 years 9 months 2 weeks 3 days 4 hours ago) and read 1652 times:

I searched but didn't find it.

Basically, Delhi just got a Cat IIIa system working on one or two runways, but should have gone for Cat IIIc.

Is there a difference in the onboard avionics between the three, or just the certification?

N


User currently offlineZak From Greenland, joined Sep 2003, 1993 posts, RR: 8
Reply 3, posted (10 years 9 months 2 weeks 3 days 4 hours ago) and read 1655 times:

some copy+paste from
http://www.airliners.net/discussions/tech_ops/read.main/73469/

ILS Categories -
xxx
Cat.I - 200 feet DH - 2,400 feet (or 1,800 feet) RVR
Metric: 800 metres of 550 meters RVR...
xxx
Cat II Restricted - 150 feet DH - 1,600 feet RVR
metric: 500 metres RVR
xxx
Cat II - 100 feet DH - 1,200 feet RVR
Metric: 350 metres RVR
xxx
Cat.IIIa - 700 feet RVR - no DH (alert height generally 50 feet)
Metric: 250 meters RVR
xxx
Cat.IIIb - 600 feet RVR - no DH (alert height generally 35 feet)
Metric: 175 metres RVR
xxx
Cat.IIIc - zero ceiling, zero visibility - "blind" landing...

RVR is Runway Visual Range, basically a distance in feet that the pilot can expect to see forward in his airplane.


The ILS equipment at the airport must be certified for it, as well as aircraft type (actually individual aircraft) and crew have to be certified.


Alert Height (AH) is not like a Decision Height (DH) -
At "DH" (obtained from radio altimeter for Cat.II) you have to make a DECISION to land or go-around...
xxx
In Cat.III operations, there is no DH... but you have to make a decision to land based on "what you see"... pilots find the DH "decision" very convenient for Cat.II, but did not exist for Cat.III...
xxx
So in "pratical operations", the AH is used somewhat like a DH, but is not regulatory. In other terms, we expect to "see the runway" at that point... which is about 50 feet radio altimeter, just about where the runway threshold is located, in Cat.IIIa minimums. In Cat.IIIb, happens at about 35 feet...
xxx
Many 747 are equipped for Cat.IIIa operations (not Cat.IIIb), although most of the "Classic" 747s (with 3 autopilot channels) have the LRCU that is required for Cat.IIIb... LRCU = landing roll control unit... keeps the nose wheel on the center line, using the localizer...

-----------------------------------------------------------
i think that sums it all up perfectly. good thing we have such knowledgeable people on the boards here like those in the thread i copied it from.



10=2
User currently offlineMD-90 From United States of America, joined Jan 2000, 8507 posts, RR: 12
Reply 4, posted (10 years 9 months 1 week 4 days 21 hours ago) and read 1477 times:

The very first airplane certified for Cat IIIa was the L-1011, and the 747 and DC-10 never came stock from the factory with that level of certification (I read that somewhere, and I'm juessing it refered to the -100, I'm not sure about the -200/-300 and obviously not the 744)

No airliner has ever been certified for Cat IIIc, because you would need some way to taxi the airplane in the literally zero visibility, so Delhi would for now be wasting their money for Cat IIIc. Especially since embedding something in the pavement for the airliners to follow would be expensive.


User currently offlineRayChuang From United States of America, joined Jun 2000, 8018 posts, RR: 5
Reply 5, posted (10 years 9 months 1 week 3 days 8 hours ago) and read 1413 times:

Actually, the wide use of GPS and the increasing availability of ground-based differential GPS transmitters could make ICAO Category IIIc operations possible at most airports. Such a GPS setup could allow an airliner to know its position within one feet (less than a third of a meter!).

I can see by 2010 many airports installing special transmitters that generate a signal for both the US-based GPS system and the European based Galileo system that will allow essentially totally-blind takeoffs, landings and ground operations.


User currently offlineEIDW From Ireland, joined Nov 2003, 44 posts, RR: 0
Reply 6, posted (10 years 9 months 1 week 3 days 7 hours ago) and read 1395 times:

There is one serious problem with zero-visibility landings and/or ground ops. In the event of an accident or problem there would surely be serious issues with the ability of fire or rescue crews locating debris, pax and even the entire plane !

Just my 2 cents.

EIDW.


User currently offlineAAR90 From United States of America, joined Jan 2000, 3474 posts, RR: 46
Reply 7, posted (10 years 9 months 1 week 2 days 17 hours ago) and read 1337 times:

In Cat.III operations, there is no DH...

AA's B738 CAT-III ops utilize a 50 foot decision height.



*NO CARRIER* -- A Naval Aviator's worst nightmare!
User currently offlineDC-10Tech From United States of America, joined Jun 2001, 298 posts, RR: 2
Reply 8, posted (10 years 9 months 1 week 2 days 9 hours ago) and read 1319 times:

Some good answers.

Aditional info:

CatIIIB must have rollout guidance, meaning the aircraft stays aligned on the runway after touchdown, if the aircraft drifts off the centerline after landing, that's considered a CatIIIA landing. At least that's how we do it at FedEx.



Forums.AMTCentral.com
Top Of Page
Forum Index

Reply To This Topic CatIII A, B, And C
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Electric Brakes And Deadstick Landings posted Fri Dec 8 2006 06:47:44 by WingedMigrator
VC-10 Hydraulic's And Control-Surfaces posted Fri Dec 8 2006 00:47:55 by Blackbird
Cooper-Harper And Flight Test posted Thu Dec 7 2006 03:21:50 by 787atPAE
Airbus And Boeing Throttle Controls posted Tue Dec 5 2006 15:30:41 by Treeny
Airport Depature And Approach Patterns posted Mon Dec 4 2006 00:51:20 by ANITIX87
A332 / Trent 772B SFC And Cruise Settings posted Tue Nov 28 2006 22:19:55 by ImperialAero
Relationship Between DC-8 And DC-9 Fuse posted Sun Nov 26 2006 10:44:45 by Speedracer1407
Using A Camcorder During Takeoff And Landing posted Sat Nov 25 2006 17:21:11 by FCA767
MD-80 And AS 261 posted Thu Nov 23 2006 03:13:59 by MissedApproach
Webcheckin And Foreign Hosts posted Mon Nov 20 2006 15:22:14 by LN-MOW
NAL Saras And The CBA-123 Vector posted Sat Feb 22 2014 15:26:07 by An225
Free FAA General And FCC Module 1 Test Prep posted Fri Feb 21 2014 16:07:49 by jettech101
Etops And Wind posted Tue Feb 18 2014 09:34:05 by goinv
Aircraft And Engine Choices posted Tue Feb 18 2014 06:34:31 by yakima
Increase In PAX Weight And Airline Performance posted Sun Feb 16 2014 10:03:25 by questions

Sponsor Message:
Printer friendly format