Compass deviation card required for VFR flight?

[MauleSkinner]

The deviation card on the Falcon 20's I flew said something like Windshield Heat must be off. Anytime the heat was supplied to the windshields the whisky compass showed one heading, 270 degrees if I remember correctly. I believe the KA's and Sabre were the same.

I freaked out a King Air captain once by flipping windshield heat on and off until I was able to get the compass to spin.

Ah, the good ol’ days!

Beechjet says the compass is unreliable with windshield heat high or defog blower.

 

[Domenick]

Hmmmmm.... y’know, now that I think about it, every card I’ve seen looked something like this:
View attachment 113468
I don’t recall seeing one that stated whether the radio receivers were on or off. I’m sure some do, but it seems uncommon, though the reg seems to require it.

Here's one from a Piper Warrior (it has since been replaced):