CAT II differences
Thread Starter
Join Date: Apr 2003
Location: Sutton
Posts: 564
Likes: 0
Received 0 Likes
on
0 Posts
CAT II differences
Can we agree that when briefing for a cat three approach the cat one plate is used (not the cat two plate).
If true please let me know why...apart from the cat two minima can't see much difference.
Anyone out there fly for an airline which disconnects the autopilot at cat two at minima (or are we all auto landing)?
Thanks in advance.
If true please let me know why...apart from the cat two minima can't see much difference.
Anyone out there fly for an airline which disconnects the autopilot at cat two at minima (or are we all auto landing)?
Thanks in advance.
Join Date: Aug 2008
Location: North America
Age: 64
Posts: 364
Likes: 0
Received 0 Likes
on
0 Posts
CAT III approach - CAT III chart.
briefing for a cat three approach
When landing CAT III(a), we brief from the CAT III(a) chart.
We can land CAT III(a) with the autopilot on, that is called called autoland (autopilot & auto-throttles on). OR we have the authorization to hand fly to CAT III(a) minimums and land using the Heads Up Display-HUD (autopilot & auto-throttles off).
We match the chart, approach briefing and type of approach being flown. The minimums will be different, the number of required RVR transmitters will differ. Our minimums are based on a Radar Altimiter for CAT III approach; vs barometric altimiter for CAT I. Also different is the legal obligation to go around due to reported weather below minimums. There may be many other differences as well.
With the HUD it is all hand flown; we disconnect the autopilot & auto-throttles fly the approach and land. That can be to CAT III, II, or I minimums.
Last edited by Northbeach; 11th Oct 2010 at 03:45.
Disconnect at Cat 2 minima.
There used to be a JAR-OPS caveat which enabled a lower minima if the autopilot remained engaged to 80% of the DH; I’m not sure if this is the same in EU-OPS.
One of the grey areas of this rule for Cat 3 was the ability to continue with manual flight after auto-land failure below DH.
If below 80% DH then the visual segment for manual flight vice auto approach should be met as this should have improved above that required for the decision pre DH.
However, between DH and 80% the ‘reduced’ visual segment might not be good enough for manual flight thus a GA should be flown.
In practical terms this is probably inconsequential for Cat3, but for Cat 2 the difference in the visual scene could be important, thus most pre-planned Cat 2 manual landings from an auto approach use a disconnect height below 80% DH.
Cat 3 approach briefing should use an ‘approved’ Cat 3 plate for your operation.
Differences? There may be different WAT limts for GA.
There used to be a JAR-OPS caveat which enabled a lower minima if the autopilot remained engaged to 80% of the DH; I’m not sure if this is the same in EU-OPS.
One of the grey areas of this rule for Cat 3 was the ability to continue with manual flight after auto-land failure below DH.
If below 80% DH then the visual segment for manual flight vice auto approach should be met as this should have improved above that required for the decision pre DH.
However, between DH and 80% the ‘reduced’ visual segment might not be good enough for manual flight thus a GA should be flown.
In practical terms this is probably inconsequential for Cat3, but for Cat 2 the difference in the visual scene could be important, thus most pre-planned Cat 2 manual landings from an auto approach use a disconnect height below 80% DH.
Cat 3 approach briefing should use an ‘approved’ Cat 3 plate for your operation.
Differences? There may be different WAT limts for GA.
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,507
Likes: 0
Received 0 Likes
on
0 Posts
From Jeppesson: never seen a CAT 3 plate. Minima come from company documents except for mid & stop which are company or plated takeoff minima. There have been airfields (LTN many years ago) which were CAT 1&3 but not 2, due to the dip in the ground before the threshold and the reaction of the RA. The G.A. should be the same for Cat 1&3. if so there should be no difference in trhe approach plate.
Join Date: Jan 2007
Location: EU
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
CAT II differences
Can we agree that when briefing for a cat three approach the cat one plate is used (not the cat two plate).
I (we) brief from the cat 2 plate for a cat 3 app, in case of reversion to cat 2 due system failure, where else would we get the cat2 min's from? (DA set to cat1 and DH set to CAT3). We don't have cat3 plates (any more) just a list with approved aiports/rwy's
Anyone out there fly for an airline which disconnects the autopilot at cat two at minima (or are we all auto landing)?
Cat 3 always autoland (no guidance to fly manually) Cat 2 both manual and autoland possible.
Can we agree that when briefing for a cat three approach the cat one plate is used (not the cat two plate).
I (we) brief from the cat 2 plate for a cat 3 app, in case of reversion to cat 2 due system failure, where else would we get the cat2 min's from? (DA set to cat1 and DH set to CAT3). We don't have cat3 plates (any more) just a list with approved aiports/rwy's
Anyone out there fly for an airline which disconnects the autopilot at cat two at minima (or are we all auto landing)?
Cat 3 always autoland (no guidance to fly manually) Cat 2 both manual and autoland possible.
Thread Starter
Join Date: Apr 2003
Location: Sutton
Posts: 564
Likes: 0
Received 0 Likes
on
0 Posts
Never seen a cat III plate (UK Jep)...or with AREAD when I used them in the 90s....but my aircraft type was only CAT II capable in those days...maybe AREADs do have cat III plates in the UK...anyonne?
XLNL...when you talk about failures reverting from cat III to cat II are you talking ground failures or a/c failures? We go around and rebrief unless its a minor issue.
Still not sure why there is a cat II plate but not a cat III and why we brief cat III from the cat one plate?
XLNL...when you talk about failures reverting from cat III to cat II are you talking ground failures or a/c failures? We go around and rebrief unless its a minor issue.
Still not sure why there is a cat II plate but not a cat III and why we brief cat III from the cat one plate?
Join Date: Jun 2000
Location: last time I looked I was still here.
Posts: 4,507
Likes: 0
Received 0 Likes
on
0 Posts
Did the BA 146 not do autopilot CAT 2 manual land? The B732 certainly did. In triple auotpilot (fail operational), depending on company SOP's, you could go CAT 3 - CAT 2 (land 3 - Land 2) due to an annunciator change. If it became worse and 'no autoland came up then it was a manula CAT 1 reversion. In my outfit if owt goes wrong on a CAT2/3 it's G/A. (fail passive). Don't know why we don't revert to CAT 1, but it's their trainset.
So I suppose if a reversion Cat3-Cat2 is possible you need to brief that minima, and also Cat 1. But what else about the approach or G/A could be different?
So I suppose if a reversion Cat3-Cat2 is possible you need to brief that minima, and also Cat 1. But what else about the approach or G/A could be different?
Join Date: Jun 2006
Location: Italy
Posts: 133
Likes: 0
Received 0 Likes
on
0 Posts
In our company we brief CAT III on CAT II plates, just then putting the DH at 50 instead of CAT II DH.
We are certify to fly CAT II with dual channel (autoland ) with RVR 300 and CAT II single channel (manual land) with RVR 350.
The only problem for us is that some 73 are certify to single channel minimum A/P height 50 ft ( so that's ok) but other 73 in single channel minimum A/P height 158 ft !!!
Can we perform the CAT II approach single channel???
thank
We are certify to fly CAT II with dual channel (autoland ) with RVR 300 and CAT II single channel (manual land) with RVR 350.
The only problem for us is that some 73 are certify to single channel minimum A/P height 50 ft ( so that's ok) but other 73 in single channel minimum A/P height 158 ft !!!
Can we perform the CAT II approach single channel???thank
Per Ardua ad Astraeus
Join Date: Mar 2000
Location: UK
Posts: 18,579
Likes: 0
Received 0 Likes
on
0 Posts
Topper - popped in here from your other thread - it sounds as if your airline tech department is in a mess! The simple answer appears at the moment to be 'yes' for the first 737s and 'no' for the second if not visual by 158'. Get them to put down their coffee mugs and Sudoku puzzles and sort it out? As for CAA flt ops........................
Guest
Join Date: Apr 2009
Location: On the Beach
Posts: 3,336
Likes: 0
Received 0 Likes
on
0 Posts
RMC:
I don't agree, at least not for the Jepp non-tailored charts for the U.S:
Can we agree that when briefing for a cat three approach the cat one plate is used (not the cat two plate).
Can we agree that when briefing for a cat three approach the cat one plate is used (not the cat two plate).
If true please let me know why...apart from the cat two minima can't see much difference.
If true please let me know why...apart from the cat two minima can't see much difference.
. The difference is the minima and the missed approach performance resulting from that minima. The missed approach from a CAT I approach may only clear terrain by 100', so a lower minima may require a different missed approach path, depending upon terrain in the area. Compare the CAT I & CAT II charts for landing to the east at Athens. Attempt the CAT I missed approach on a CAT II or III from the minima and you will find yourself "terrain embarrassed" 
Anyone out there fly for an airline which disconnects the autopilot at cat two at minima (or are we all auto landing)?
CAT II may be manually flown, but requires flight director guidance. (requires certified training)
CAT III must be an autopilot approach. (requires certified training)
My company saves on the training cost for CAT II manual approach (with flight director) by simply requiring CAT II approaches to be flown as autoland - thus the sim time spent for CAT III certification also covers CAT II (autoland).
Join Date: Jun 2002
Location: Wor Yerm
Age: 68
Posts: 4
Likes: 0
Received 0 Likes
on
0 Posts
Anyone out there fly for an airline which disconnects the autopilot at cat two at minima (or are we all auto landing)?
PM
Last edited by Piltdown Man; 29th Oct 2010 at 13:53. Reason: Spellung, agin!
Only half a speed-brake
Also some of the A32S without proper SB are autoland limited above 2500 pressure alt. Hence, if the ELEV is more than that autopilot disconnect is a must. However I do not see a reason to do so when not required and both company and manufacturer's guidance seem to agree.
Yours,
FD (the un-real)
Yours,
FD (the un-real)
