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Fail Passive and operational

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As an opponent to autolands and someone who hasn't even toyed with them since the original NG, I'm curious about the use of fail versus operational. I've been doing some LIFR and BCAT1 landings for a change of scenery but tonight left me confused.

 

I feel I understand the overall difference between the two; however, fail passive should still autoland. I flew into KIND tonight with 200 foot ceiling and fog with 0.75 mile visibility reported. Of course the runway was black until below 200, and technically I should have gone around, but I wanted to how see how it played out. I armed CMD B and watched as the AP kicked me just below 200 feet AGL.

 

I was configured properly, 140 knots, flaps 30, everything armed, and so forth. I do not have failures enabled so what logic boots the AP in this case? I can't think of a reason LAND 2 wouldn't have armed.

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Hello,

 

Keeping in mind I'm no expert, and someone soon will come along and find PLENTY of faults with my list, but take it for what it's worth, my personal notes on the requirements for getting autoland to work in the PDMG 737 in the list below.  I put this together for myself one day after constantly getting frustrated why I couldn't get it to work.  It only takes one small thing to not be correct and it won't work.  For me, meeting this criteria gets the job done:

 

Use the digital standby instruments

FMC set to "Fail-Operational" although I have read fail-passive works I've had trouble with that mode

Both Pilot and Copilot Flight Directors set to "ON"

Both Course Indicators (pilot and copilot) set to the same runway alignment

Both NAV1 radios tuned to the runway localizer

Flaps 25+ degrees

Speed Brake Armed

Autobrake Set to Level 1 or Higher

Gear Down

Localizer Captured

Enable CMD, VERT, and LATERAL nav modes to "ON" (actually only CMD A may need to be on)

Set Autopilot to APR (approach) when the ILS localizer and glideslope aligns or is getting close to alignment

Set Autopilot to dual CMD (press both CMD buttons) after APR light goes out or AGL < 1500 ft. (If CMD A and CMD B stay lit the battle is nearly won)

"LAND 3" appears only after ~1500 AGL on the Radio Altimeter

"FLARE", "ROLLOUT" should appear as enabled and then later as deployed

 

On passing the runway threshold I flip off the autothrottle and pull the throttles back to idle.  After touch down, engage reversers.

 

Apologies again for any errors in my list, it may error on the side of having more things than is strictly necessary.  The manual that comes with PDMG has the steps in it also, and it doesn't hurt to practice the Tutorial #1 over and over again (I've done the tutorial 3 times now and could use a refresher myself). 

 

Mark Trainer

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When did you arm CMD B?

 

I have no idea, but above 1000 AGL, probably upon LOC and GS alignment?  Perhaps it was too early?  As I mentioned, I don't like autolands but once in a while is fine.  I haven't done one since the original NG in FS9.  The landings are the fun part anyhow.  I wasn't even going to use it last night since minimums were reported as CAT I, but the runway was completely dark until almost 180 feet AGL.  Looked like I was gonna land in a field, lol.  I managed to land fine but it was odd.

Hello,

 

Keeping in mind I'm no expert, and someone soon will come along and find PLENTY of faults with my list, but take it for what it's worth, my personal notes on the requirements for getting autoland to work in the PDMG 737 in the list below.  I put this together for myself one day after constantly getting frustrated why I couldn't get it to work.  It only takes one small thing to not be correct and it won't work.  For me, meeting this criteria gets the job done:

 

Use the digital standby instruments

FMC set to "Fail-Operational" although I have read fail-passive works I've had trouble with that mode

Both Pilot and Copilot Flight Directors set to "ON"

Both Course Indicators (pilot and copilot) set to the same runway alignment

Both NAV1 radios tuned to the runway localizer

Flaps 25+ degrees

Speed Brake Armed

Autobrake Set to Level 1 or Higher

Gear Down

Localizer Captured

Enable CMD, VERT, and LATERAL nav modes to "ON" (actually only CMD A may need to be on)

Set Autopilot to APR (approach) when the ILS localizer and glideslope aligns or is getting close to alignment

Set Autopilot to dual CMD (press both CMD buttons) after APR light goes out or AGL < 1500 ft. (If CMD A and CMD B stay lit the battle is nearly won)

"LAND 3" appears only after ~1500 AGL on the Radio Altimeter

"FLARE", "ROLLOUT" should appear as enabled and then later as deployed

 

On passing the runway threshold I flip off the autothrottle and pull the throttles back to idle.  After touch down, engage reversers.

 

Apologies again for any errors in my list, it may error on the side of having more things than is strictly necessary.  The manual that comes with PDMG has the steps in it also, and it doesn't hurt to practice the Tutorial #1 over and over again (I've done the tutorial 3 times now and could use a refresher myself). 

 

Mark Trainer

 

 Hmm, weird.  I always tune both CRS and NAV radios.  My brakes were at 3, flaps 30, speed 140, speedbrake armed, gear down.  Same as I'd do for non-ILS actually.  Only difference is me kicking off automation on final somewhere.  I even had the HGS set up and I don't really use it.

 

Now I feel compelled to try autolands just to see what the issue is and that takes the fun out of flying :mellow:

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Hi,

 

I don't have access to the manuals for now, I need to reinstall my NGX but have you tried to search "Land 2", "land 3" and "no autoland" in the FCOM v2?

You will find there the conditions required for the first two modes to work and the reasons why you could have the third notation.

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Hi,

 

I don't have access to the manuals for now, I need to reinstall my NGX but have you tried to search "Land 2", "land 3" and "no autoland" in the FCOM v2?

You will find there the conditions required for the first two modes to work and the reasons why you could have the third notation.

 

My search didn't really reveal much.  The mention of fail operational is much more frequent, almost insinuating that fail passive isn't autoland approved.  I read online though that it should be.

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You don't have land 2 land 3 in the 37 as you do the 67. It's just a Flare annunciation on the PFD. You lose an autopilot, you lose the auto land capability.

 

Jack Colwill

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You don't have land 2 land 3 in the 37 as you do the 67. It's just a Flare annunciation on the PFD. You lose an autopilot, you lose the auto land capability.

 

Jack Colwill

 

Fail Operation 737s  are rare  (JAL is the only airline I know of that has it). They do have the LAND 3/2. Most 737s that do autoland just have the FLARE.

 

Cheers.

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I'm wondering if PF works for anyone in the sim.  I used an AAL 738 to fly from PHX to SAN and armed CMB B.  I was properly configured in stable air.  I got the flashing LOC/GS, and it just continued on close to minimums, then disconnected.  :rolleyes:   

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I'm wondering if PF works for anyone in the sim.  I used an AAL 738 to fly from PHX to SAN and armed CMB B.  I was properly configured in stable air.  I got the flashing LOC/GS, and it just continued on close to minimums, then disconnected.  :rolleyes:   

Chris,

 

By PF do you mean Fail-Passive?

 

I am doing short flights into KSAN to test a holding pattern.

I am using Fail-Operational and autoland is ok.

 

If you are asking if Fail-Passive autolands (No-Rollout) work (I assume they do) I could give it a test for you?

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Chris,

 

By PF do you mean Fail-Passive?

 

I am doing short flights into KSAN to test a holding pattern.

I am using Fail-Operational and autoland is ok.

 

If you are asking if Fail-Passive autolands (No-Rollout) work (I assume they do) I could give it a test for you?

Yes, Passive-Fail. Apparently most airlines only have PF (no rollout), which is fine, but mine disconnects before minimums every time. Somewhere around 350' AGL. I'd rather use the PF option if that's what airlines use but I doesn't seem to work for me.

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Yes, Passive-Fail. Apparently most airlines only have PF (no rollout), which is fine, but mine disconnects before minimums every time. Somewhere around 350' AGL. I'd rather use the PF option if that's what airlines use but I doesn't seem to work for me.

Ok,

 

But first, you mentioned:

"I'm wondering if PF works for anyone in the sim.  I used an AAL 738 to fly from PHX to SAN and armed CMB B."

 

Did you only have CMD  "B" on .... or "A" and "B" on for approach and landing?

 

 

And just to verify: "but mine disconnects before minimums every time"

What exactly is disconnecting .. do you have e.g. a screenshot or video of you panel to show?

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Haven't done one in a while but fail passive has worked fine for me every time I've tried it. Only minor difference I see is with the HGS - AIII mode works fine to include rollout guidance (minus the distance remaining info), but the rollout annunciation doesn't illuminate on the HGS status panel. No biggie.

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Ok,

 

But first, you mentioned:

"I'm wondering if PF works for anyone in the sim.  I used an AAL 738 to fly from PHX to SAN and armed CMB B."

 

Did you only have CMD  "B" on .... or "A" and "B" on for approach and landing?

 

 Yeah

And just to verify: "but mine disconnects before minimums every time"

What exactly is disconnecting .. do you have e.g. a screenshot or video of you panel to show?

 

I only use CMD A when I fly, just makes more sense even though there's no difference. So for auto land I arm CMD B, meaning both APs are on for my arming autoland.

 

And by disconnect, I mean "NO AUTOLAND" displays and the AP disconnects just prior to minimums.

Haven't done one in a while but fail passive has worked fine for me every time I've tried it. Only minor difference I see is with the HGS - AIII mode works fine to include rollout guidance (minus the distance remaining info), but the rollout annunciation doesn't illuminate on the HGS status panel. No biggie.

I'd love to know how. I do everything correct AFAIK and no dice. Tune both NAVs, CRS, APs, stable approach with flaps at 30, gear down, speed at Vref + wind factor, and all the things you'd do for a normal ILS approach. I even arm LOC then APP before hitting that second AP

I won't be able to post a screen for a little while. I work 12s and I'm only one day in this week.

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Fail Operation 737s  are rare  (JAL is the only airline I know of that has it). They do have the LAND 3/2. Most 737s that do autoland just have the FLARE.

 

Cheers.

By pure coincidence I am looking through Virgin Australia cockpit pictures and noticed one of the 2012 deliveries has fail op on a 737-800 VH-YIF - David Lee

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By pure coincidence I am looking through Virgin Australia cockpit pictures and noticed one of the 2012 deliveries has fail op on a 737-800 VH-YIF - David Lee

 

Got  a link?

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Got  a link?

search airliners dot net for the reg, VH-YIF its one of the first pictures in their db of a panel shot you can see the fail op button

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search airliners dot net for the reg, VH-YIF its one of the first pictures in their db of a panel shot you can see the fail op button

Where's the fail op button?

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Where's the fail op button?

To the left of the autobrake and above the upper EICAS screen. See there is the little panel with 2 buttons in a row and a single small button to the bottom right but nothing left? The bottom right button is the fail op button - David Lee

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To the left of the autobrake and above the upper EICAS screen. See there is the little panel with 2 buttons in a row and a single small button to the bottom right but nothing left? The bottom right button is the fail op button - David Lee

Oh, I've had planes with that button before but on ours it just brought up the brakes and flight controls, iirc.

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Oh, I've had planes with that button before but on ours it just brought up the brakes and flight controls, iirc.

The top left is the engine status page. The top right is for the hydraulic systems and some carriers have brakes and flight controls on the same status page. But the bottom right button is the fail op button - David Lee

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The top left is the engine status page. The top right is for the hydraulic systems and some carriers have brakes and flight controls on the same status page. But the bottom right button is the fail op button - David Lee

I noticed that extra button when I looked at the pic you linked. But what does it do? I've only ever flown planes with fail-passive autoland capability, but my rough understanding is that operationally they're set up pretty much the same way - arm Approach, then select 2nd (and/or 3rd) autopilot.

 

What does that little button do?

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