GPS Question- Activating the approach

[iggy0075]

I have a quick question.  When is the best time to activate your approach, and then to activate the vectors to final.  

Replies would be great.  

THANKS
JWM

[beefhole]

Assuming you're flying IFR, the best time to activate it is when ATC gives you your first vector, so you have heading hold on instead of Nav hold. (having Nav on will make the plane fly directly towards the approach)

As soon as ATC gives me my first vector on descent I immediately load and activate the approach.

[wji]

When ATC states:"Cleared for the approach."

[beefhole]

When ATC states:"Cleared for the approach."

aka when they give you your first vector