View Full Version : CAT3A landing

4th Oct 2008, 12:12
CAT2 and CAT3A landing with autopilot is stronger required or manual control possible too? Give the doc ref PLS.

4th Oct 2008, 14:07
Not an ATC question - better to ask in a Flight Desck forum, maybe Tech Log. Perhaps a mod will move it for you??

4th Oct 2008, 14:55
AFAIK, Cat II and III approaches are fully automatic. Don't have a document reference to hand at the moment - I'm sure someone will point you to one.

4th Oct 2008, 15:22
Doc 9365-AN/910 Manual of All Weather Operations doesn’t make it clear…

4th Oct 2008, 15:54
Certainly for Cat II there are some operators/aircraft that have been approved for manual/coupled approach and landing. I think it's largely left up to the CAA of the relevant State what they approve or require beyond the international standards.

You may find something of interest (at least for the European region) in ECAC doc 17, albeit it seemed to be becoming a little dated when I last needed it, if you can find a copy. It was always difficult to find on the web but now seems to have disappeared when I had a quick look - perhaps it has been withdrawn or updated into some other document, maybe JAR-OPS.

4th Oct 2008, 16:09
You have to segregate approach category CAT I CAT II CAT III A CAT III B with autoland capability, they are 2 separate things.

CAT I CAT II usualy performed on Auto Pilot then they are followed with a Manual LANDING.
CAT III A ( which is can be viewed as an improved CA II or a degraded CAT IIIB) usualy performed on Auto Pilot which includes an autoland.
CAT IIIB is full auto land.
BTW I flew to Almaty from Seoul in 1997, Freezing fog viz 50 meters, I had to hold for 2 hours to have CAT II minima amd land :}

4th Oct 2008, 16:20
SPITOON thanks for ref…not sure that a crew will be try to land with RVR350 by manual, it look like a suicide…but why no?

4th Oct 2008, 16:29
KIJANGHIM we got CAT3A for RWY23R now and u are welcome!

4th Oct 2008, 16:33
Embraer 145 , Falcons are CAT3B manually flown...as per flight manual, only CAT 2 are autopilot flown..
CAT3B in these aircrafts requires Head up display..

Just need some practice..

4th Oct 2008, 16:49
KIJANGHIM, if I understood correct, during CAT2/3A any a/c approaches by AUTO till DH than goes manual landing.

4th Oct 2008, 17:18
Like somebody before correctly pointed, you have to segregate CAT 1, 2, 3 from the autoland capability an aircraft can have.

Cat I can be flown manually or autopilot coupled down to minimums. The landing can be manual (most cases) or automatic (if the aircraft is able), but some restrictions apply because the CAT I ILS signal accuracy is not guaranteed below CAT I minima, therefore closer attention has to be paid by the crew in case they elect to do an autoland.

Cat II has to have an autopilot functional in order to start flying the approach. If it subsequently fails , you can still continue, it just depends where it fails on you, but this is another discussion.
CAT II can be landed manually or autoland. This is legally speaking. Some companies elect to prohibit manual landings from a CAT II approach, others simply cannot do that because their aircraft do not have autoland capability. (Ex: most regional jets, ATR's, SAAB's, EMB).

CAT IIIA- You have to have 2 (or more) autopilots functional AND autoland capability. For some aircraft (and I can offer you the example of the SAAB 2000) you can have a Head Up Display instead of the autoland capability, this is the only case when you can manually land the airplane following a CATIIIA. Otherwise, autoland.

CAT IIIB - You have to have autopilots and autoland capability.

The discussion can go further into if the autopilots are fail passive or fail active, different company's procedures and so on, but it would be too long.
Ref:JAR TGL 23, jar awo, etc

4th Oct 2008, 18:00
Greetings, ALATOWER,

Providing that LVP is in force, and the Aircraft and crew are AWOPS (All Weather Operations) certified/qualified and that the civil aviation authority of the destination Airport, has given the airline permition to operate under LVP
CAT II providing that when you reach the DH you have visual clues in sight in such a way that you can assess that a safe landing can be made, if you which this landing to be made manually then you can do it manually, if you wish to use autoland then use auto land.
CATIII operations are based on an approach to touchdown using the autoland system.The only exeption is HUD equipped aircraft certified CAT III with manual landing, B737 is one of them.
BTW you have very nice country, landscape is breath taking:eek: and you guys you party like crazy :eek:

5th Oct 2008, 02:27
Thanks for everyone’s responses to this. Have a good weekend.

5th Oct 2008, 19:34
It's depending on the airline. Some german airlines fly CATII approaches manually.

West Coast
6th Oct 2008, 06:07
Cat II has to have an autopilot functional in order to start flying the approach

Perhaps per your SOP's, but not everyones.

6th Oct 2008, 21:42
The procedure for landing in Cat II or Cat III will be given in the Flight Crew Operating manuals.

Whether it is possible to fly such an appraoch manually or only on AutoPilot, depends on the aircraft type and equipment.

Some aircraft may have equipment, such as a Head Up Display with flare guidance, that make it possible to do the landing manually, even in bad visibility.
Some aircraft may fly so slowly that a manual landing may be possible in Cat II conditions, this might apply to some turboprop aircraft.

However, the usual way that aircraft builders have made Cat II / III operations possible, is through multiple AutoPilots that fly the approach all the way to an automatic landing.

7th Oct 2008, 08:50
Then I have a question regarding this Manual landing of Cat II and III. Regarding the B737 once you have both APs coupled and around 800ft the FLARE mode will be armed, and around 300ft the trim will go off and trim it nose up for the flare. How would any pilot want to take over that arcraft in that trimstate at 50ft to do a manual landing with the HUD, or is there a way to inhibit the FLARE mode and triming (which im sure there is).


7th Oct 2008, 15:40
What are you trying to talk about:confused: and what are you trying to demonstrate:confused: Aircrafts equipped with CAT II CAT III HUD DONT HAVE AN AUTOPILOT FOR CAT II and CAT III :eek: zero, zippo, nada :=
They are fitted with a HUD because a HUD is cheaper then an CAT II/III autopilot. :ouch:

7th Oct 2008, 17:33
It is just down to economics;

A CAT3 autopilot, not even considering the autoland, autobrake capability is VERY expensive and time consuming in certification. As a consequence some manufacturers elected to certify CAT3 approaches manually using a HUD;

This is the case of Dassault and the Embraer 145 (i do not know the others).

Example : Falcon 2000 EASy

CAT2 ------> Autopilot flown HUD stowed minimas 110 ft

CAT2-----> Manual flown HUD 2 deployed minimas 100 ft

CAT3-----> Manual Flown HUD 3 Deployed minimas 50 ft

If the HUD is deployed during CAT 1/ CAT2 approaches and autopilot is ON, the approach guidance cue will be displayed down to 100 ft in CAT1 and autopilot disconnect on CAT2 (50ft the latest); leaving only raw data displayed in the combiner.

The flare cue which is represented by a + + will show within specific conditions, at least 10 seconds before touchdown :uhoh: and not less than 20 ft...:zzz:

7th Oct 2008, 17:40
Not correct. The 737 can be equipped with fail operational autopilots and a very nice HUGS too. So you can do autolands with automatic roll out or do manual CAT II/III landings with manual thrust, your choice.

Even the classic can have both at the same time (though not fail operational with automatic roll out), did my typerating on a simulator equipped with a head up guidance system and tried some manual cat III approaches, works like a charm.

However i am not sure you can mix both operations, as we never officially trained on the HUGS i do not know if there is a procedure for late switch-over. But even on the normal 737 (without HUGS) you are normally trained to take over and land manually after the nose up trim has been applied.

7th Oct 2008, 18:28

Redundancy is a good thing but CAT II/III autopilot and HUD with the same capability :confused: I dont think airlines will pay for both, now as an option if you want both that a good business for the airframer.
A simulator equipped with both makes sense, it is a device that provides TRAINING....

Second you cannot and shall not use both at the same time :=
because whatever provides guidance shall provide information i.e., FD bars, and for your information HUD has its own sources, Gyros, computor, recievers.
NOW if the HUD is just interfacing (like in the Airbus) i.e., duplicating what is on your PDF then you can use it to look through it, BUT NOT TO MAKE A CAT III MANUAL :ok:

7th Oct 2008, 20:53
Actually it was installed in the simulator so Delta could train their pilots there as they had the HUD installed on their classic fleet. And the classic can do normal dual autopilot autolands for cat 3 anyway.

And it is installed on the BBJ as standard, that one has fail operational autopilots with auto-rollout as well, of course that is not used in airlines but is certified to the same standards.

The 787 will come with dual HUGS as standard, although the autopilot system most certainly will be able to provide CAT III capability without it, will be interesting though if you can do manual CAT III landings with the HUGS alone or if it is just there to provide head up flying in all types of approaches will be interesting.