A tricky problem!

[gaxan]

We operate a Schiebe Falke SF25C motor glider, recently the canopy was replaced and the framework required welding. Since then the wet compass has been useless- impossible to swing and gives errors in excess of 50 degrees! We suspected that the canopy frame had become magnetised during the welding process and we tried to de-gauss it using a television de gausser - to no avail.
Anyone out there with any sensible ideas on how to cure this problem?

[Whopity]

Have you tried another compass in the aircraft. i.e. is the problem caused by aircraft magnetism or has the compass itself been damaged?

[Heston]

And similarly take the compass out of the aircraft and check if is OK remote from any metal objects.

Welding does certainly cause horrible magnetic effects. What gets magnetised depends to some extent on where the earth return cable is attached during welding.

H

[DeltaV]

I had this problem too some years ago and did manage to de-gauss it with a TV de-gausser, but it took me several tries to get it done and initially I made it worse. From recollection my early attempts were too close to the frame.

I reckon I must have looked like a StarWars Jedi knight fanboy waving my light sabre about in the back garden.