PMDG 737-800 NGX autopilot engage

[mh8794 0]

I recently started to fly the PMDG 737-800 NGX.

 

I am having troubles using the autopilot.

 

here is what i did;

 

I create a flightplan from MILANO MALPENSA (LIMC) to FRANKFURT AM MAIN (EDDF) entering the SID, route, but leaving the STAR empty.

This because i don't know the runway to land on. I usually enter these when receiving information from destinations ATIS.

 

I engage both FD before take-off and setting the altitude, speed and heading.

 

Once taken-off, waiting for 1000ft, i try to engage the pilots 'CMD', but it does not work. I get a green light on the button when clicking on it, but i immediately turns off once i release the button.

 

I am not touching the yoke at that time, the gear is up. The Autotrottle works.

 

Even when i am flying level at cruise altitude and trying to engage autopilot, it does not work.

 

So i flew the entire flight manually using the trim.

 

Can someone help trying to find the missing link here? i am sure i am missing someting, but i don't know why.

 

Thank you

[Piper9t3 25]

Did you engage the pilot's side FD before the first officer's side?

[alexmfishburn 2]

The autopilot will only engage above a certain altitude AGL, from the radio altimeter. You can change this value in the fmc, in the pmdg setup menu. I have it at 800, I think the default is 1500 ft.

Also, check that the disengage bar is raised before you press the button, otherwise it will disengage.

You can also set in the fmc if you want to hold wigs level or go to the selected heading after TO. I think the default is wings level.

 

Hope this helps,

 

Alex.

[mh8794 0]

@ Piper9t3

 

I did set the pilot's side FD before the co-plits

 

@alexmfishburn

 

I usually try to engage it after 1000ft, but i tried numerous times do it at higher altitudes.The disengage bar was raised.

I will check which settings are set in the FMC menu...

[alexmfishburn 2]

One thing that is modelled is the override of the flight controls over the AP. so if you are applying force on the controls the AP will automatically disconnect. Make sure the controls are neutral before engaging the AP

[mh8794 0]

I did not touch the controls when trying to engage AP.

But it does not engage.

 

Is there any setting of fuel pump,s hydraulics, electrics which has anything to do with the AP?

[alexmfishburn 2]

Hmm. Very odd indeed..

Not sure! I would suggest getting in touch with PMDG support tbh!

 

Hope you find a solution

 

Alex

[Fonzzy 2]

Hello mh8794, 

Are you using LNAV and VNAV modes to fly or are you giving raw real time data to the autopilot such as turning the heading selector knob once a turn in your route comes up?

Did you complete the entire FMC? This means the POS INIT page, the Route Page, The PERF INIT PAGE and your TAKEOFF REF page? Remember you also have to execute the Route Page and the PERF INIT page.

 

Cheers

[mh8794 0]

Hello mh8794, 

Are you using LNAV and VNAV modes to fly or are you giving raw real time data to the autopilot such as turning the heading selector knob once a turn in your route comes up?

Did you complete the entire FMC? This means the POS INIT page, the Route Page, The PERF INIT PAGE and your TAKEOFF REF page? Remember you also have to execute the Route Page and the PERF INIT page.

 

Cheers

i will try now. I guess i haven't completed the FMC with regards to the TAKEOFF REF and haven't set the trim correctly.

i would like the AP to follow the flightplan, so i guess i need to set LNAV and VNAV?

[Fonzzy 2]

 

 

i would like the AP to follow the flightplan, so i guess i need to set LNAV and VNAV?

Yes you would need to set LNAV and VNAV to complete your flight.

Since you are new to flying it, I would recommend reading the NGX Introduction and the NGX Tutorial #1 if you would like to get a sense of how LNAV and VNAV work and how to set it up

 

Cheers

[BIGSKY 316]

If realistic autopilot engagement is selected in the CDU PMDG menu,The a/c has to be in trim.

[mh8794 0]

I have done another test in another flight.

 

I don't know what solved my issue but i used another Livery for the PDMG 737-800 NGX from Delta Airlines (previously i used Ryanair) and noticed that the MCP looked a bit different.

 

Was it a bug in the Ryanair livery or was it because this time i trimmed the plane correctly before takeoff?

I am not sure. I will try to reproduce it with the Ryanair livery with the correct trim settings...

[alexmfishburn 2]

You'll find some liveries have a accurate config to the real world. So if delta uses the Collins MCP, and the livery has a red asterisk on the pmdg website, it will come with all the right options as default. Have a look in the pmdg options menu and you can change it

 

[mh8794 0]

You'll find some liveries have a accurate config to the real world. So if delta uses the Collins MCP, and the livery has a red asterisk on the pmdg website, it will come with all the right options as default. Have a look in the pmdg options menu and you can change it

Ryanair livery indeed does not have the red asterisk. But i doubt this is the reason why the A/P is not working as they are saying that it has the same options as the PDMG default livery:

 

* - denotes this particular livery has a fully accurate and verified airline options configuration included. 

 

Every attempt is made to place known options into the liveries based on photos and video but ones without the asterisk are incomplete in some way. Liveries for which no known information on options exists will have the same configuration as the PMDG House Livery. If you have a complete and verifiably correct option configuration for any livery, please email us the ini file and we'll update it and give it an asterisk!

[Spin737 102]

 

 

The autopilot will only engage above a certain altitude AGL, from the radio altimeter.

I don't think that is the case. I believe it's a certification limitation and has no Rad Alt input for engagement. 400' is the minimum per the Approved Flight Manual. Airline SOPs vary.