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.

If traffic and weather is good I'll usually handfly the thing up to FL150 or even up to FL250.

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.

It gets it altitude data from the radio altimeter.

But, it gets it data on altitude from the radio altimeter.

The A/P doesn't look at Rad Alt for you to engage it on take off is my point. 800' and 1500' sound more like climb power reduction points. I don't think that's Rad Alt, either.

I think it says somewhere in Tutorial 1 where the minimum AP activation alt is at 400'

Ok, people. I will refresh this thread, cause I find, that it will be the right place for my problem.
 

So I am standing in front of a riddle, I cannot solve. Since a point of time, that I cannot remeber, I cannot use the Autopilot A in my 737/800 NGX from PMDG anymore. Only the Autopilot B is in function.

The situation is, that the Master Flightdirector is on the pilot's site switched on, the green LED is showing it. So it is clear, that it should be possible, to operate the plane by the Autopilot A. But as soon I will use it during the flight, I cannot switch on  the Autopilot A. The green LED of the Autopilot A  stays switched off. I have to switch on the Autopilot B. As soon as I have switched it on, the Master Flight Director LED on the Copilots seat is on and the Master LED on the Pilot's seat is switching off and the plane is operated by Autopikot B.

 

In case of the fact, that I can not use both Autopilots, it is not possible to autoland thr plane, if neccessary or if I want to do so, cause for autolanding both Autopilots have to be engaged and switched on.

Can anybody help me to solve this problem?

And please, if possible, kepp your language easy, cause I am not a native speaker and my understanding of english is less than everage. ;-)

 

Thanks for the helping hands, guys.

Full names in the PMDG forums please, see also the pinned forum rules for explanation.

 

It is hard to tell what you are not doing correctly because you did not provide any information on the sequence of events leading up to the attempt to engage A/P A.

 

The easy way to solve this is to fly Tutorial #1 that comes with the product and compare the steps you take there with your own work flows. Give it a try.

You need to have a roll mode and pitch mode active with the FD on and the airplane in trim for the autopilot to engage. Roll mode can be HDGSEL instead of LNAV. Pitch mode can be either V/S, LVLCHG, or VNAV. You need to engage those first I read through the thread and could not verify if you are satisfying this requirement unless I missed something. To select VNAV and LNAV is already mentioned what you have to do in the FMC.

What do you mean with full names in the forums rules, Dan? Sorry, but I am not a very well english speaking person, so I do not really understand, what you mean.

But back to the problem. I solved it now.

 

I broke  the 'sheer bolt' by applying too much force on your yoke while the AP was connected. This prevented me from being able to use CMD A. I had to fix it by using the service via the PMDG SETUP > MAINTENANCE pages.

It is fantastic, how PMDG simulates the plane. They thought even those things, like operatingmistakes and the results of it.
 

May be this information will help other fellows here, if they have the same problems.

Kind regards Robert.
 

Hello Robert, what Dan means is best done by adding your full real name under which you bought your PMDG aircraft. Forum rules.

Best done by editing your signature and it will appear automaticaly on every post.

 

Glad you solved your problem--yes, you broke the autopilot !