I set a heading, then arm heading select while still on the ground, (HDG SEL on PFD in green) after engaging toga and taking off, reaching the set altitude and the plane switches to the heading I had armed, except it is not going on the heading value that is set, it is going on a strange heading. Due north or something. Does anyone else see this? I have to press HDG hold, then press SEL again and the airplane finally goes on the proper heading angle.

Hi, David,

 

Maybe this fix, addressed in the PMDG issues thread, will take care of your problem:

 

- Roll mode behavior below 400 feet after takeoff corrected. It is now possible to select modes other than LNAV.

 

Mike

Yes, it seems the LNAV and Heading Hold are the only modes that can be armed properly on the ground. I didn't notice till now because I'm usually flying RNAV departures, or "Airport Name" "Number" departures which are "Runway heading till xxxft then radar vectors" (in which case heading hold or not arming any lateral mode is appropriate).

 

But being assigned a "After takeoff turn left/right xxx°" by tower with your takeoff clearance, you can't grab heading select armed/on till after takeoff.

 

Looks like that's gonna be an SP1 fix as noted by Mike above.

The only two modes that can be armed on the ground ,On the Real 777, before takeoff are LNAV and VNAV! (well, and TOGA ofcourse).

 

They stay white!

White = armed.

 

So heading can not be armed on the ground.

If a heading needs to be flown, Heading Select would normally be selected in 400ft (and not earlier because many airlines have in their SOP: No turns after take off before 400ft unless absolutely required).

Real 777: Heading Select CAN be selected once airborne before 400ft but as I said, many airlines wait untill 400ft)

PMDG777: Does not allow Heading Select to be selected once airborne before 400ft. This is corrected in the quoted fix in SP1

 

To be honest, I never tried what happens if you try to arm Heading HOLD before take off.

As far as I know, it should not be possible to arm Heading Hold nor Heading select.

The fact that it turns green shows that it is not armed but engaged.

You dont want Heading Select or Hold engaged on the ground, You want TOGA!

You should select Heading Hold/Select at 400ft or above.

 

That Heading Hold engaging is possible on the PMDG777 on the ground could be (I think it is) a (minor) PMDG bug that results in the strange behavior the OP described in his first post.