PMDG 737-700 Problem

[Hai Perso Coyone?]

Hi all,
my PMDG 737-700's autoilot does not do heading turns. as a result i have to do all turns manually. can seomone please tell me as to wht has happend. i have engaged autopilot. the altitude hold works fine just the heading hold trun switch doesn't work. soppsing i feed in left heading 170 and the plane is flying at heading 340. the plane doesn't turn and the ATC says "... please expedite your turn heading..."

I'm new to the PMDG 737's. I also read their manuals but nothing there either.

Thanks,
Ashar

[jrpilot]

I realy don't know what to say but I have experienced something similar to this...I will put a heading of 200 on the autopilot (A/P) and the A/P will fly a heading of 210 or so


make sure you have LNAV off

[Nexus]

In Juniors case; the answer is very simple.

Look at the compass arc on the ND.
Does it say HDG XXX MAG
or
TRK XXX MAG

I believe it says track, no?  :)

[jrpilot]

So what should I do?

[Nexus]

TRK 190 MAG
The aircraft will track 190 degrees magnetic
Whereas
HDG 190 MAG
Aircraft will point the nose to 190 degrees magnetic

Understand the difference?

[jrpilot]

Ok I understand the difference but how do I get the aircraft to go a heading of 190 (meaning the nose will point a heading of 190)

I use the HDG button on the MCP


Or are you saying the aircraft already (even though the nose is faced in a different direction) going a heading of 190

[Nexus]

PMDG  737 has (as far as I know) only the option to TRACK. In real life, the TRK/HDG is an avionics customer option I believe.

However, the 777 can switch from HDG to TRK select with a push button located on the MCP.
Here are some pics
Boeing 777 With HEADING, and TRUE as the north reference (important when flying high latitudes)


Boeing 737 with TRKand MAGnetic north as reference


again a 737, but this time with HDG and MAG.

 :)

[jrpilot]

so are you saying that when jets with the TRACK/MAG funstion are being vectored around by ATC they arn't going to be flying the same as the jet that opted to go with the HDG/MAG function?

[Nexus]

Oh yes they will.
The TRK 190 MAG only refers to the orientation of the ND. The track line will always be straight up and your track will be displayed on the ND arc, NOT THE HEADING!  :)

Here look at these examples. In both cases I have selected a heading of 338 in the MCP panel. In the first pic I'm flying in the VOR mode (tracking radial 344), which is heading orriented. So my heading bug will be straight on top (HDG 338 MAG)


In the 2nd case I'm flying in map mode, which is TRACK oriented. And I also have a crosswind from the left so a wca is required to compensate for the drift. Still flying the same heading 338, but the ND is giving me a compass track of 343. Notice also the magenta heading bug displaced slightly to the left of the top center