So I promised to contact King Schools for clarification about this question in another thread. However, that other thread got a bit tangled with multiple topics so I'll post the followup here for easier reading. To recap... In the King video Martha said yes, you are required to fly to your filed alternate. However, the response here was: So one of the course creators (I'm slightly disappointed it wasn't Martha herself) emailed me back and cited FAR 91.185(c) and 91.185(c)(1)(iv) which says: "If the failure occurs in IFR conditions, or if paragraph (b) of this section cannot be complied with, each pilot shall continue the flight according to the following: <list of things> ...by the route filed in the flight plan." And apparently they take that to include the filed alternate. However, he did give the caveat that if your alternate is also below minimums and you are running low on fuel then you could and should invoke FAR 91.3 by declaring an emergency and go where you need to go. But it sounds like in a lost comms situation you can't deviate from your filed alternate (assuming it's legally and safely flyable) simply because someplace else is better.