GPS and Compass 180 deg difference

[EVVFCX]

Hi all,

Thought I'd start having a go at the worlds 10 most dangerous airports.

Started at Lukla VNLK, switched on GPS with intention of flying out of the valley and return.

GPS is showing heading as being 180 less than  (reciprocal )of runway direction, compass shows correct heading and so does Shift Z.


GPS's graphic of runway is also different to what I see.
Tower view is also 'miles' away.

There are graphical problems in this area anyway, I've not noticed this problem anywhere else before.

regards

Steve

[dave3cu]

The GPS (in FS anyway) has no magnetic input so no sense of heading while standing still. It calculates the heading track by comparing GPS positions while moving.

It's not uncommon for it to disagree with the compass, when you start a flight, until you begin taxi.

**Corrected-I must pay closer to my terminology...

[Brett_Henderson]

The GPS (in FS anyway) has no magnetic input so no sense of heading while standing still.

No sense for heading while moving either..  the GPS deals with; direct-track (DTK) (if there's an active course/waypoint), and actual-track (TRK).

Heading (direction the nose is pointed), is of no use to the GPS.