A question about using navigation that's plaguing me.

Thanks! BTW, does it unblock ALL the grayed out buttons (like on the phone). Thanks again and sorry for hijacking this thread!

 

What really irritated me was that it had the turns on the screen, issued the message, and then suddenly removed the turns it was showing. What's the justification for that? If it doesn't have all the cross streets, fine, just say things like "left turn in one tenth mile" instead of "next left". Just don't take away a route that's already been shown the driver (with no indication that I had to memorize it in the next second).

 

When routing to my house, I get the "can't continue" message, even though the street is shown, and so are the addresses within that street. Go figure.

As for radio devices in airplanes, the problem is that radios aren't completely passive. They do have oscillators to mix with radio frequencies in the air, and using the difference between the 2 frequencies as the chosen intermediate frequency which is fixed. Since the intermediate frequency is fixed, filters and amplifiers can be finely tuned. The radio frequency to receive is chosen by varying the oscillator so that the difference matches the IF. This is known as the heterodyne receiver, which just about all radio receivers use.
Since there is at least one oscillator emitting radiowaves, it could potentally interfere with the airplane's navigation, though that possibility is very slight.