hey boys n' gals,

Did it ever happened to you that you saw on the NOTAMs that the "ABC VOR is U/S" (un serviceable), but while flying to the ABC VOR it was working perfectly?

If it happened to you too, and it sure did to many here, you were probably wondering for what reason is that NOTAM up in the air.

As far as I know when it says "ABC VOR unmonitored" it means that it might be working but it's not legal to count on it as a navaid (specially in IMC), since it's not being monitored for integrity and/or operational status.
But I always thought the "ABC VOR U/S" meant that it's not working.

So what does it mean if not that it's just simply not working?