Hi all,

 

This one has been bugging me for quite a while now: I am trying to fly the tutorial from Gatwick to Schiphol, but autoland is putting up a fight. Here's what I do, see if you can spot what's wrong:

 

a. I pass NIRSI, deploy flaps 1. No DRAG REQUIRED AFTER NIRSI message at any time.

b. 2.5 miles from EH608, I press the STD button as I pass through 4000ft, as set as transition altitude for our descent. Confirmed 1013 hPa displayed.

c. Immediately after b, I press VOR/LOC, confirmed armed (white) VOR/LOC text on PFD. Plane turns onto approach, green VOR/LOC text, flaps 5.

d. I press APP, confirmed green G/S text. LNAV and VNAV MCP button lights go out, as in the tutorial. e. I press CMD B, confirmed both CMD A and B are lit.

f. Manual speed setting 147 kts, confirmed SPEED button (or whatever it's called) lit.

g. Both eng start switches set to CONT.

h. Flaps 15 set when flaps 5 maneuver speed reached.

 

At this point, the text SINGLE CH comes up on my PFD, indicating that autoland is not available. I have to add, I've followed the tutorial step by step, including setting course 184 on both dials on MCP, setting both NAV radios as per the tutorial, and all other steps, using Pause whenever a lot was going on, checking my route and FL, etc.

 

Can anyone tell me what I'm doing wrong? Thank you :)

 

 

Sincerely,

 

- Tom

And what does happens after this point? Just continue normal operation.

LAND3 can be activated at altitudes between 500ft and 1500ft radio altimeter.

Like, rsvit, I say to wait until it is annunciated. Like he said, it can engage as low as 500ft. Also, when showing us fixes, an approach plate would be helpful, as I (and I'm sure others) have no idea what any of that means without an approach plate.

And make sure, that you have chosen fail operational and NOT fail-passive in the config.

With fail-passive yellow SINGLE CH will change into CMD.

Hi Tom,

 

I have this same thing happen to me also. Just carry on with your approach and it will most likely autoland with the yellow single ch on the PFD. It does for me. I don't really know why it was doing the yellow single channel thingy, but I figured after I've flown enough routes and read enough of the manuals the answer would come.

 

 

Ed

Thank you guys! After posting this thread, I eventually found another thread here on AVSIM concerning the same problem - and ending with the same solution - as this thread. I will see what the fail- thing is set to, and see if it changes anything. And sorry for not posting an approach plate, this is my first move from VFR to more serious flight sim'ing. I'm still in the learning process.

I'll report back with my results!

 

- Tom

Sorry to ask, but what is the key difference between fail-passive and fail-operational, and how do I change between the two?

Sorry to ask, but what is the key difference between fail-passive and fail-operational, and how do I change between the two?

 

FCTM 5.26-5.29. You can change it in FMC equipment options. If you choose more presice fail-op, you will get MCP from Rockwell Collins and ISFD. There are some differences in procedures also.

FCTM 5.26-5.29. You can change it in FMC equipment options. If you choose more presice fail-op, you will get MCP from Rockwell Collins and ISFD. There are some differences in procedures also.

 

Thank you very much for your answer.

 

I flew the approach a few times since, and eventually the LAND3 message did show, but I wasn't able to activate CMD B until about 500 ft radio alt - anytime I pressed it above 500 ft, the CMD B would not activate. Is this SOP on this aircraft, or a flaw in the PMDG plane, or just me mishandling the systems?

You can engage second autopilot after G/S capture and not below 800ft.

 

but I wasn't able to activate CMD B

 

What does exactly happens after you press CMD B: CMD B not activating or CMD A reverts into CMD B and both autopilots are not working together?

What does exactly happens after you press CMD B: CMD B not activating or CMD A reverts into CMD B and both autopilots are not working together?

 

CMD A stays active, CMD B button is lit for a second, then goes out.

 

But just to make it clear, I did manage to land in full CATIIIb mode, but I got down to about 500 ft AGL before LAND3 activated.

CMD A stays active, CMD B button is lit for a second, then goes out.

 

But just to make it clear, I did manage to land in full CATIIIb mode, but I got down to about 500 ft AGL before LAND3 activated.

 

Before arming the second autopilot make sure the glideslope has been captured. Both lights will stay on but 'LAND3' will only appear once through 1500 feet

Some points:

 

-EVERY SINGLE NGX CAN AUTOLAND. People will tell you you need to activate fail operational option. THIS IS NOT TRUE, DO NOT BELIEVE THEM. These people do not understand what are they talking about.

 

-Connect second AP unit when APP mode is active. You can also do this before G/S capture, but APP needs to be active.

 

-It is normal to get SINGLE CH annunciation after full ILS capture on autoland. This indicates that while both AP channels are armed, only one is active so far. Self-check and activation sequence will commence at about 1500ft, and you will then have CMD (or LAND2 or LAND3) annunciation shown shortly - only panic if this is not shown after passing 800ft.

 

-Notice that FLARE is armed. (ROLLOUT too on fail op option)

 

-also make sure both radios are set.for the ILS frequency and course. While the 737 is perfectly capable of landing on single radio signal, you need to have both radios set so that there is fallback if one of them fails in critical moment.

 

 

Autoland in the 737 almost as it should be done (this was unscripted and late nght, but it worked OK, just some minor methodical errors):

 

Notice that this is with the FAIL PASSIVE option, which is what an overwhelming majority of the NGs have.

only panic if this is not shown after passing 800ft.

 

500 feet is altitude for checking active modes. 800' is the minimum altitude of connecting the remaining CMD.