I noticed last night when trying to set the stab trim for takeoff I could adjust nose down but not nose up until I pulled back on the yoke for elevator up. First time I've experienced this on any aircraft. Anyone else?

 

Maybe a controller issue. Not really sure at this point.

I noticed it once, I can trim up (i.e. numbers go up) but not down. I also noticed that the speaker knob on the rearmost audio panel (on the Aft Aisle Stand) gets pushed in whenever I trim down. I couldn't trim on the ground using either the hardware controller or keyboard, so I had to use the alternate stabilizer trim switch to set take-off trim. The problem disappeared once airborne.

I noticed it once, I can trim up (i.e. numbers go up) but not down. I also noticed that the speaker knob on the rearmost audio panel (on the Aft Aisle Stand) gets pushed in whenever I trim down. I couldn't trim on the ground using either the hardware controller or keyboard, so I had to use the alternate stabilizer trim switch to set take-off trim. The problem disappeared once airborne.

Thanks lain. Glad to see I'm not the only one to experience this. Very strange behavior regarding the speaker knob when trimming down. Haven't noticed that but will check tonight when I get home. I guess this isn't a big issue as long as I CAN trim somehow. Very odd though.

 

Thanks again.

In the 747, like most Boeings, you can't trim in the oppositie direction to the column position. So if your column is pulled nose up, you can't apply nose down trim. Could be a controller calibration issue. Or it could be the column cutoff is too close to neutral in the PMDG sim, in which case PMDG needs to fix it.

Thanks Kevin, that's probably it. My yoke may have been deflected up, so I can't trim down. That speaker knob thing is a bit odd however.

I have the same issue, without touching the yoke, I can trim down but I can't trim up using the trim buttons on the yoke, although, using the trim nub inside the airplane seem to work. very odd thing, I never had this issue with any other plane including pmdg. 

 

Evan