Autoland function und A/T

[tokem79]

Hello, everyone. I have a problem with the Final Approach with and without autoland. If I want to use the autoland function, I cannot activate both autopilots (CMD A and B) at the same time. Only one turns on at a time and the other turns off a short time later. Also: is it correct, that Autothrust needs to be disabled just prior to touchdown? I would be very happy about a short answer. Happy landings!

[Fleng200]

You need to select FAIL OPS in the PMDG options.

[Ephedrin]

for the 2nd autopilot being turned off make sure you fulfill all requirements. Most commonly people forget to set the ILS on BOTH NAV receivers.

[Stearmandriver]

You need to select FAIL OPS in the PMDG options.

Nope, Fail Passive will autoland just fine.

Leave the autothrottles and autopilot engaged until after touchdown, then disconnect them both.

To autoland:
1. Both (captain and first officer) flight directors on.
2. Both nav radios tuned to ILS.
3. Both inbound courses set.
4. On an intercept heading.
5. Arm Approach mode.
6. Turn on Both autopilots - this is the only time that selecting the second autopilot will not deselect the first.
7. At approximately 1200ft above ground, a self-test will occur and if it passes, the Single Channel autoflight annunciation will change to CMD, and you'll see the Flare mode armed as a vertical mode on the flight mode annunciator (in fail passive.)
8. After touchdown, disconnect autopilot and autothrottles, deploy reverse, maintain centerline.

[geoffda]

4.5. Both the glideslope and localizer indicators are alive in the PFD. Don't arm approch before that.

[SeatonTower]

Nope, Fail Passive will autoland just fine.

It will autoland just fine, but only using a single AP. Fail Operational allows for 2 APs to be engaged.

[Stearmandriver]

It will autoland just fine, but only using a single AP. Fail Operational allows for 2 APs to be engaged.

Nope still. Fail passive uses both APs. There's no way to autoland using a single AP.

Our fleet at work is Fail passive; we very definitely need to use both APs.

Fail Operational just uses a third axis of the autopilots for yaw, allowing the aircraft to track centerline after touchdown and thus lower vis requirements... unless you monitor the approach with the HUD in Aiii mode with rollout mode, which is what we do. Then fail passive autoland achieves the same landing minima as fail operational.

[SeatonTower]

Nope still. Fail passive uses both APs. There's no way to autoland using a single AP.

Our fleet at work is Fail passive; we very definitely need to use both APs.

Fail Operational just uses a third axis of the autopilots for yaw, allowing the aircraft to track centerline after touchdown and thus lower vis requirements... unless you monitor the approach with the HUD in Aiii mode with rollout mode, which is what we do. Then fail passive autoland achieves the same landing minima as fail operational.

I stand corrected. Just read the related section in the Boeing Operating manual too. I assume then that Fail Operational AP operation isn't an option on the real aircraft? It's not mentioned anywhere in the manual.

[geoffda]

It is an option in the real aircraft. PMDG wouldn't have made it available if it wasn't. Both the FCOM and the FCTM mention it.

[Stearmandriver]

Oh yeah it's an option. Often, fleets that don't equip with HUDs will choose fail Operational for the rollout control. I actually did not know there were even different choices here until I started using the NGx back in FSX. PMDG has taught me a lot about how varied 737s can be all over the world. When you learn an airplane at an airline, you learn their planes and that's it... never talk about options your fleet doesn't have.

So TL;DR - both fail passive and operational modes will autoland just fine, using both autopilots.

[rpotor]

4.5. Both the glideslope and localizer indicators are alive in the PFD. Don't arm approch before that.

You Sir are now my hero. :-) Over the weekend, I did my usual "new airplane test flight" route of LHBP - LOWW for like a gazillion times and for the life of me I couldn't figure out what I was doing wrong and why CMD B was not engaging to perform an autoland. I double, triple, quadruple checked that everything was set up correctly and still it was not autolanding. I saw on the FMA that VOR/LOC roll mode was annunciated correctly but at glideslope intercept, the pitch mode was G/P instead of G/S. I figured this was a problem, but couldn't figure out why it was doing a G/P mode approach when clearly an ILS approach was selected in the FMC and all the frequencies and courses and whatnot were correct.

So, after I read your post today during lunch break in my office, I thought okay, I must try this. And sure enough, following this bite sized wisdom of yours was the magic solution. If I waited with arming APP until the glideslope indicator started moving, all was well and CMD B played nice. So thank you very much for enlightening me and most likely many others who in the future will happen to find this post after almost going nuts with the autoland apparently not working.