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Elsmoko

MD11 Autoland Question

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When autoland is properly engaged, sometimes the AP will disengage when nearing touchdown.  Not a big deal > it helps to hone

reflexes and teach flexibility ~;)   however, can anyone tell me what circumstances (wx conditions, etc)  cause this behavior.  My

controllers are not spiking and I've had the correct ILS freqs set in all cases.

Best to all,

Ken

 

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I have kind of had this issue also, maybe the same as you decribe where dual land is showing then changes to loc( or app) only and the A/P disengages at around 500ft.

I was going to post this on my own thread but seeing as it is quite sinilar i hought i would just add on to this thread.

Apologies for the hijack if the smptoms are not similar.

 

Regards
 

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Are you sure you are landing on a runway that is CATIII capable?  If not, then you can't carry out a full autoland.  And besides, landing is the best part.  Why sit back and let the plane do it for you? B)

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Are you sure you are landing on a runway that is CATIII capable?  If not, then you can't carry out a full autoland.  And besides, landing is the best part.  Why sit back and let the plane do it for you? B)

 

If there is an ILS approach in FSX to any runway a full Autoland can be done on that runway.

 

Michael Cubine

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Are you sure you are landing on a runway that is CATIII capable?  If not, then you can't carry out a full autoland.  And besides, landing is the best part.  Why sit back and let the plane do it for you? B)

I don't know about cat 3 or whatever, but its happened a few times at an airport where it will flare itself one time and disengage another, - ie there is no consistency.

 

Thanks anyway

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The CATIII requirment is for real world only, FSX and the PDMG MD11 does not care if the runway you are landing on is CATI, CATII or CATIII, as long as you have a valid ILS and G/S the plane will do a full autoland. The only time I have had this happen was at KBUR. That was because the ILS and/or the G/S at KBUR cuts off before you get down to the runway. I do not know about now, but back then it was the same way in the real world. For some reason on Rwy 8 at KBUR they wanted you to take manual control a mile out or whatever the distance was and it was setup the same way in the Navigraph data base I had at the time for the PMDG MD11.

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The only reason it will drop out of autoland (especially DUAL LAND) is due to system failure, system error, loss of signal, or out of flight parameters.

 

Check that you do not have the option for flight controls to override the autopilot, too, as this can also force a disconnect of the autopilot system, even in autoland.

 

Best regards,

Robin.

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Hi Robin,

 

Thanks for the heads up, although I do normally leave the controls alone till its flaring, then I hit the F2.

 

It disco's around 300-800ft, - the former being the most frequent.

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IIRC, depending on the approach type, you enter the MDA altitude into the FMS, then passing that altitude, the FMS forcibly disconnects the autopilot.

 

Are you definitely selecting the correct approach type in the FMS? ILS will NOT ask for this value.

 

Best regards,

Robin.

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i pretty much fly only Europe and dodge about.

 

All i can really say is for example if im going down the ils 28 @lpfr odemi2k hit FR607 @5000ft hit a right turn to establish, - it will turn onto the ils and descend fine.

 

I know VERY little about flying, but on my fms, i hit my last waypoint>star>then select ODEM2K and ils28 - hit insert then on the next page i get APPR TRANSto LPFR (in tis case GEBTI or VFA) i normally leave this alone - i guess you may say "this could be the issue" and i wont argue with that as i do not know any better, - but seeing as this is what i do ALL the time, sometimes it flares fine, and sometimes A/P disco's.

 

I hope you see where i am coming from? :)

 

Thanks

 

Paul

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Ken, Paul,

 

a common mistake to cause autopilot disengagement shortly before touchdown is that the LAND mode did not engage. You will then see a APPR ONLY on the FMA. The main cause for this with the PMDG pilots in the past was they were not at landing configuration when passing 1500ft RH. It is at THAT point where LAND mode is armed, and if you are not at landing flaps (35 or 50) at that point, you will get APPR ONLY, and this will cause the AP to disconnect later on.

 

Hope this helps!

Markus

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Markus,

 

You are a star, so basicly full flaps by 1500ft, I normally drop my gear about 1800ft, and then give it 35 flaps, so in that case I must be just lower than the 1500ft that's required.

whats RH?

 

Regards

 

Paul

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RH = Radio Height

 

Basically the height above the ground, measured by your radio altimeter.

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You are a star, so basicly full flaps by 1500ft, I normally drop my gear about 1800ft, and then give it 35 flaps, so in that case I must be just lower than the 1500ft that's required.

 

Paul,

 

extending the gear at 1800ft RH is fine if you fly in CATI or better with a manual landing to follow the ILS. Just be careful to be at Vapp, gear down and landing flaps when reaching 1000ft RH.

But if you're doing a low visibility approach CAT II or III then you should slow down earlier, not just because of the AFS and its 1500ft limit for an autoland. This will also help to have more time for the important monitoring required for such an approach.

 

Cheers,

Markus

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As far as I'm concerned flaps/gear are deployed by speed. And runway length and Wind... Not by altitude?

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Paul,

 

extending the gear at 1800ft RH is fine if you fly in CATI or better with a manual landing to follow the ILS. Just be careful to be at Vapp, gear down and landing flaps when reaching 1000ft RH.

But if you're doing a low visibility approach CAT II or III then you should slow down earlier, not just because of the AFS and its 1500ft limit for an autoland. This will also help to have more time for the important monitoring required for such an approach.

 

Cheers,

Markus

Hi markus, thanks

 

All my speeds are controlled by my fmc anyway - i notice that the fmc slows me down way too early, so i have to manually raise my speeds by raising it and right clicking the knob.

 

I normally am at full flaps(35) well by 1000ft, as i say - about 1800 its gear down then once thats done i hit full flaps (fs2crews order).

 

Could this also be why when i hit the ils, i do not go down the glideslope? i do turn and get the callouts that its alive, but wont start to descent - even though im at the 3000ft(or whatever height required).

 

Sorry to be such a noob.

 

Regards

 

Paul

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Paul,

 

no, gear and flaps have no influence on whether the AP captures the G/S or not. Unless of course you'd try to do that at 340kts ;)

What does the FMA say once you're on the glide but the AP does not descend? Maybe post a screenshot of exactly that moment?

 

Markus

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I haven't noticed anything different about any displays to what's "normal for me" Markus.

 

Next time I will take a screenie.

 

what's/where's FMA? :rolleyes:

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Hi,

flyingnoob, on 21 Jul 2013 - 11:21 PM, said:

what's/where's FMA? :rolleyes:

Right in front of you, above the attitude indicator. The gray box which is seperated into 3 parts. It shows you very important information about what your autoflight system is doing.

From left to right the boxes show the following:

1. Box: Shows you information how the autoflight system (or the FD when handflying) is maintaining the speed. This can be:

- "PITCH" - pitch for speed

- "THRUST" - throttle for speed

- "IDLETHRUST" - idle descent mode, also pitch for speed

To name the most important ones.

 

2. Box: Shows you information how the autoflight system (or the FD when handflying) is controlling at the latteral axis. This can be:

- "HEADING XXX" - flying a heading

- "NAV1"/"NAV2" - following the FMS commands

- "VOR1"/"VOR2" - following the VOR indicator

- "LOC ONLY" - following the localizer

- "LAND ARMED" - autoflight system is armed to land the plane

To name the most common ones.

 

3. Box: Shows you information how the autoflight system (or the FD when handflying) is maintaining altitude constraints. This can be:

- "CLB THRUST" - Climb thrust is set

- "HOLD" - Altitude hold

- "APPR ONLY" - No land mode. AP will disconnect at 100ft AGL.

- "GS" - Maintaining the glideslope

- "DUAL LAND" - Doing a full automatic landing. That's what you'r looking for.

To name just a few.

 

For further information refere to page AUTO.30.26 in the Systems manual (page 160 in the PDF).

 

Best regards,

 

Jonathan

 

EDIT: You might also want to have a look at page PT.30.4 i nthe Flight Crew Operating Manual (page 367 in the PDF). It explains what you should do when and what the aircraft does while you perform an automatic landing.

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Thanks guys,

 

@bread - ok I didn't know that, I always put ils freq in manually, the panics I've got into while trying to search for charts online looking for it.

 

 

@Jonathon,

I hit APR to arm landing (land armed highlights) then when I am going down the loc I get my dual land, (from memory) it, then would change itself to loc only, appr only.

 

The "appr only" as you describe is what has been happenening where A/P disengages and leaves me to fend for myself - (anything above having to hit F2 on landing leaves me in a panic  :unsure:  ).

 

Thanks for the in-depth description :) - I tried looking at the manual once before and thought "oh dear" and it's not been out since!!

I'm not good at reading stuff I don't understand, - I can read, but when there are so many abbreviations for stuff, it goes right over ones head!

 

Thanks again guys

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Paul,

 

extending the gear at 1800ft RH is fine if you fly in CATI or better with a manual landing to follow the ILS. Just be careful to be at Vapp, gear down and landing flaps when reaching 1000ft RH.

But if you're doing a low visibility approach CAT II or III then you should slow down earlier, not just because of the AFS and its 1500ft limit for an autoland. This will also help to have more time for the important monitoring required for such an approach.

 

Cheers,

Markus

 

Hi Markus, could you tell me? What would be normal company policy regarding "autoland", I mean is it mandatory or can you choose to land manually?

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No, an autloand is normaly not mandatory. Autolands are normaly performed for two reasons:

 

a ) The weather at an airport requires an autoland. If there is little forward visibility and/or a very low ceeiling it may be neccessary to fly an CAT II or CAT III ILS approach. If not equipped with a HUD (like the NGX) those approaches must be flown by the autopilot.

 

b ) As everything in aviation an automatic landing should be trained, so that it works out when needed. So many airlines say that a pilot has to do one automatic landing a month. So if you don't encounter bad weather for a longer time, it can happen that you will have to perform an automatic landing in weather which wouldn't require one, because one of the crew members hits that limit.

 

Please note: In FSX you can do a CAT IIIC landing at every airport equipped with an ILS. This is not the case in the real world. Many smaller airports only have an ILS which is capable of ILS CAT I appraoches.

The number of airports which allow CAT IIIA or even CAT IIIB (automatic landing including rollout) landings isn't very big.

As far as I know the only airport in the world, which ILS is capable of providing CAT IIIC (automatic landing including rollout in 0 visibility (which means in theory the crew doesn't have to see the runway, even when the aircraft is on the ground)) is London Heathrow. Again, as far as I know, it is still not possible to do such a landing, because Heathrow doesn't (or didn't) have some neccessary detector loops on taxiways and roads arround the runway and ILS installations, which are neccessary to monitor if the runway is clear and the ILS signal isn't disturbed by the catering truck, who's driver got lost in the thick fog.

 

As said, that is only as far as I know and that information might has changed by now.

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