Cant get Autopilot to follow flightplan with default 747

I've seen this mentioned many times but not yet found a solution that works.

 

I created a flight plan and ATC recognises it, so no problem there.

 

On departure I followed ATC instruction until it told me to resume own navigation. Seemed to be working fine but later I realised it was a coincidence that my heading was the same as my flight plan. When I got to my first VOR the aircraft started to turn but then just kept turning. Tried this a few times but same thing happened.

 

Tried GPS on it's own.

Tried GPS NAV

Tried GPS APP

 

All to no avail. My autopilot is working ok because it cantrols all the other parameters, Speed, Hdg, Flight Level, etc. I mention Hdg because I've even tried GPS HDG (knowing that wasn't going to work)

 

So, where am I going wrong?

I've seen this mentioned many times but not yet found a solution that works.

 

I created a flight plan and ATC recognises it, so no problem there.

 

On departure I followed ATC instruction until it told me to resume own navigation. Seemed to be working fine but later I realised it was a coincidence that my heading was the same as my flight plan. When I got to my first VOR the aircraft started to turn but then just kept turning. Tried this a few times but same thing happened.

 

Tried GPS on its own.

Tried GPS NAV

Tried GPS APP

 

All to no avail. My autopilot is working ok because it cantrols all the other parameters, Speed, Hdg, Flight Level, etc. I mention Hdg because I've even tried GPS HDG (knowing that wasn't going to work)

 

So, where am I going wrong?

 

Have you programmed a flight plan? No point in using GPS in anything other than HDG mode unless you have set up a plan!

Did you happen to miss a contact with ATC? If so, they'll drop you like a hot potato. An easy check for this is to bring up the ATC window and look to see if it says "create and IFR flight plan". You then will have to say OK to your original plan and ATC will get you back on course.

Yes to flight plan. ATC follows the plan on departure,

 

No to missed instruction. I'm particularly careful about this because I've read of others having the same problem

NAV/GPS switch in the NAV position?

 

Try opening up the GPS gauge and see how the plane is flying it. The current leg will be highlighted pink. It almost sounds like you've got an extra waypoint in the plan, or the plane is flying past a waypoint, but not close enough to it that it's not tripping to the the next leg. If it's the first, just take out that waypoint from your flight plan. If the second is what's happening, the plane will fly circles around the waypoint, trying to get close enough to it to trip to the next leg.

 

I've had that happen to me a couple of times, especially on take offs. i stray off the plan enough because the tower wants me to fly 'runway heading', then they will tell me to turn to..... and proceed, only to find out the waypoint we just far enough away that the plane started to circle around. I was able to get into the GPS and tell the plane to fly to the next waypoint. In cases where I have a crazy departure, I will set the GPS and NAV on about 30 seconds or so after I takeoff, and let the plane find it's way.

Yes, I seem to remember, a few years ago, having the same issues with departures.

 

But good news ......... my problem's sorted. Just used GSP NAV. Why that didn't work previously I have no idea, but it's working now.

 

Thanks for all the inputs.