Hi guys ,

 This morning i made a couple autolands ( normally land manual ) at kmia rw8r , and everytime i get a land 3 so no problems , bur what does it take to get a land 2 instaed of a land 3 .

II had a different baro setting left 1001 and right 1004  , my left DH was set to DH 83 the right setting was set to BARO 283 , and even the right flightdirector was off and still land 3 flare roll out with no problems  so whayt does it take to go from land 3 to land 2 , and yes i read the manual .

 

Hope someone can help me with this

 

Thanks in advance ,

 

Gérard

Now, how can I explain this in few words...

 

The number you see after LAND (2 or 3) represents the number of operational systems the AFDS (auto flight director system) self test identifies (between 1500ft and 500ft during approach) as available for autoland

 

LAND 3 means:      3 Auto Pilots, 3 Radar Altimeters, 3 ILS receivers, 2 ASA   are available

LAND 2 means:      2 Auto Pilots, 2 Radar Altimeters, 2 ILS receivers, 2 (or zero) ASA  are available

 

In both cases the plane will autoland NO PROBLEM. The differences would all be in the applicable landing minima (with Land 3 you're in CAT IIIB; with Land 2 either in CAT IIIA - if ASA is available - or CAT II - if ASA not available).

 

So, if you want to experience a LAND 2 message on your ASA, set one of those 4 systems inop, but don't forget to apply the applicable minima for landing

 

Sorry Gérard, was trying to make it simple. There would be quite a talk to explain all the downgrading philosophy, but probably it wouldn't be that much of an interest for Sim purposes.

 

Hope it helped

Very good explanation, Francesco, as I too was looking for an insight into this.

Hi Francesco ,

 

Thanks for the explanation ..

I tried to set both radar altimeters to a different setting and was hoping to simulate the right radar altimeter wasn't working, switched the left fd of and let the right fd on but it still gave me land 3 .It seems that if you perform a autoland on land 3 and the right engine fails land 3 degrades to land 2 so i m gonna try that tomorrow

 

Thanks ,

 

Gérard

No Gérard, with an engine failure the airplane is still able to fly CAT IIIB (LAND 3), and changing the readings of Radio alt or switching off the F/D is "fresh water" (as we say in Italy) to the airplane. Doesn't do anything.

Readings of the radio alt are just for you as a reference (in CAT IIIB you don't even display the reading. You switch it off, because you don't need it as the minima for ceiling is "0")

I'm talking about SYSTEM FAILURE.

 

If an ILS transmitter fails on the ground, or onboard (although I think with this sim you cannot discriminate which ILS should fail, I believe it fails them all), then you get a LAND 2.

If one of the 3 autopilots fails (in real life you would not even notice), then you get a LAND 2

And so on with the other 2 systems.

So, it has to be the SYSTEM itself to fail, not you trying to trick the AFDS.

 

Unfortunately I still haven't had the time to play much with this sim, so I still don't know precisely what failures you can simulate (funny I bought it a couple of days after its release JUST for this purpose and I still have to look into it...), but try go in the FMC failure settings and look for one (or more) of those 4 systems.

If you can select what system to fail try it out and see what happens.

Just REMEMBER:

777 has 3 indipendent systems for Auto Pilots, 3 for Radar Altimeters, 3 for ILS receivers, and 2 for ASA

You ONLY have to fail maximum one for each of them, otherwise you will get a "NO AUTOLAND" EICAS msg, and you're in CAT I now

 

Sorry, not easy to explain in a language that is not yours, but I hope I got my msg through.

If you need more clarification I'll try again

Hi Francesco ,

 

It makes sense what you say that a system should fail instaed of a wrong input by a pilot  as i tried to do with the setting of one of the  baro . so thanks for explaining it .

I m gonna take a look in the failure setting nad see if it works ,

 

Thanks again for helping out .

 

Gérard

Hi Gérard!

 

This is from FCOM-Limitations-Operating limitations page: Automatic landings can be made using flaps 20 or 30, with both engines operative or one engine inoperative. The autopilot flight director system (AFDS) autoland status annunciation must display LAND2 or LAND3.

 

Hi Francesco ,

Thanks for the explanation ..
I tried to set both radar altimeters to a different setting and was hoping to simulate the right radar altimeter wasn't working, switched the left fd of and let the right fd on but it still gave me land 3 .It seems that if you perform a autoland on land 3 and the right engine fails land 3 degrades to land 2 so i m gonna try that tomorrow

Thanks ,

Gérard

:smile:

Hi Norbert ,

 

I read those pages ( yes i read the manuals  :lol:  ) too but it doesn;t say what is the cause that it degrades from land 3 to land 2 ,and land 2 is still a autoland ( and how to simulate this as it's a real fcom ) but maybe i can set a failure in the fmc to get a land 2

 

 

from the 777 intro page 0.00.136

 

 

If you are performing an autoland and suffer an engine failure of the left engine during LAND 3, the airplane will continue in LAND 3. If you are performing an autoland and the right engine fails during LAND 3, the airplane will degrade to LAND 2. This happens because the airplane is able to maintain three sources of electrical power if the left engine fails because the battery charger (the third source) traces power back to the AC Main R bus. If the right engine fails, that bus goes unpowered for just a moment, which causes the battery charger to drop offline for a moment. Your airline can purchase a pin option to prevent this and allow LAND 3 regardless of engine failure, but they figured you could live without it…

 

Thanks ,

Hello Gérard!

 

My understanding is that the LAND3 that displays at the top of the PFD (autoland status annunciation) is actually in reference to the capabilities of the autopilot itself as opposed to the actual category of approach. For example, you can fly a normal CAT1 approach with a DH of 200 feet or so and the PFD will still say LAND3 because everything is working correctly.

 

And if i'm not mistaken all ILS approaches in FSX are simulated as CAT3 capable only.

 

And when you have AP (whether one or two active APs) with ATHR on you are able to do a CAT3 approach.
With AP only (if im not mistaken) you are able for CAT2
And without AP you are only able for CAT1.

 

as soon as you are downgrading during approach, for example you are established on LOC and GS with AP and ATHR on, and now you are turning off your autopilot, you are getting downgraded to CAT1.

 

Regards. :Peace:

Hi Norbert ,

 

That's correct it has nothing to do with a cat1 or cat 3 app but with the autopilot systems  itself .

I just did a flight and in the fmc i programmed a right baro failure and this time i did get a degraded land 2 message because there was a failure . , , first a eicas message no land 3 status  and in the fma land 2 .When i clicked the lading checklist ( altimeters ) it directed me to the non normal checklist  which brought me in the no autothrottle section saying left autothrottle was off but i still could use the right autothrottle , i didn't switched them off so im a litle confused , When there is  a problem with the right altimeter does this have effect on the left autothrottle  ?

No.

There is no relation between alt and A/T.

Besides, even with one autothrottle the airplane is still capable of LAND 3 performance