Hey guys, bit of a newbie here, so please bear with me.

I'm doing a lot of GA IFR flights with a simple flight plan of one airport direct to another.  I notice on some flights, I'll get vectors to the ILS approach. On others, I'll get clearance to the ILS approach, but no vectors that follow.  

Typically I'm noticing that if the approach the ATC is setting me up for has multiple "legs" or turns, I'll get those vectors.  Usually the ones without the "legs", i.e., an approach that is straight in, is the one where I'm not getting the vectors to turn and intercept that approach.  So some general questions:

1) Are there procedural reasons why I might get vectors to the approach in some scenarios, but only clearance in the others?

2) When cleared for an ILS approach, is a pilot generally free to change altitude and heading on his own?

I guess what I'm asking is when cleared for approach, how do I know I should wait for further instructions (heading and altitude) vs. just proceeding on my own to intercept the approach?

And finally, are the answers to the above questions different where RNAV/GPS approaches are concerned?

Thanks!

 

You will get vectors when the turn to final is a sharp turn or if a transition is involved and the last waypoint of the transition is a manual termination (which is usually the case when the turn to final is sharp).

When cleared for the approach, you are cleared to follow the lateral course and altitude restrictions in the approach, regardless of the type of approach.  In the case of an ILS, you will follow these to intercept the ILS glideslope.  

Dave

Thanks Dave!