I know this discussion is very US centric, but I thought some may like to know that in Canada too there is often confusion about the need for a magnetic compass. However, the CARS (regulations) are clear that a glider needs only an airspeed indicator and an altimeter. They do, however, specify that a powered glider must also have a magnetic compass. Further, any glider with the ability to carry water ballast must also have an outside air temperature guage.

Also interesting is the confusion about the need for a compass correction card. Everyone thinks it is necessary yet the regs here say that it is only necessary if the compass is off by at least 5 degrees at any point. Quite sensible, I would think, and it is far better than our AME's simply making up some numbers on a card as is often the case (rather than doing a proper compass swing.) It is amazing how something that should be quite clear results in so much confusion among people in the industry.