ATC start-up clearance
Hi,
At some airports that have a specific Delivery frequency, I've heard it common to just request the IFR clearance to you destination. And in that case, ATC might sometimes answer with start-up approved, and as far as I'm aware that only means that they have opened the flightplane, and not actually that you can start the Engines?
But at some smaller Airports with no DLV frequency, it seems common to just request start-up and the clearance in the same call - and as a respone to that ATC will give you the start-up clearance, but in this case does it mean that you can start the Engines since you started of by asking for start-up?
If that is the case what is the difference, and why does some Airport prefer if you directly ask for start-up clearance, instead of start by just requesting the clearance, or is it the same thing?