mulligan
Cleared for Takeoff
So I have been flying lots of IFR legs between KBHM and KBTR. When picking up clearance for return in KBTR for some reason they always ask what's your course to first waypoint. It's usually somewhere around 056. Then I get the clearance
Cleared to BHM as filed via radio vectors on departure fly runway heading to 3,000 expect 9,000 in 10 minutes departure frequency 126.5 squaw xxxx
Filed KBTR EWA KBHM which is basically a direct route and that is what always comes through.
On takeoff tower always assigns a heading and then says contact departure.
The heading is usually a few degrees off my filed route I'm sure for traffic avoidance.
When checking in with departure I inform normally but add on assigned heading. They identify and all is normal. I then get handed off to the next airspace, the next airspace, the next airspace while every time informing I'm still on assigned heading. Usually around half way I contact center and say I'm still on assigned heading and then they always go, oh, I thought you were direct, cleared direct to Birmingham. I say thanks and go direct.
My confusion is clearance was as filed which was KBTR ewa Kbhm but assigned heading being 4 degrees off over a 2 hour period actually puts me a good ways away. Why do they say as filed and then give vectors not as filed? Wouldn't it be easier to just give clearance as cleared to BHM via radar vectors and leave the old as filed off? Or is the as filed just there incase of radio communications loss?
Cleared to BHM as filed via radio vectors on departure fly runway heading to 3,000 expect 9,000 in 10 minutes departure frequency 126.5 squaw xxxx
Filed KBTR EWA KBHM which is basically a direct route and that is what always comes through.
On takeoff tower always assigns a heading and then says contact departure.
The heading is usually a few degrees off my filed route I'm sure for traffic avoidance.
When checking in with departure I inform normally but add on assigned heading. They identify and all is normal. I then get handed off to the next airspace, the next airspace, the next airspace while every time informing I'm still on assigned heading. Usually around half way I contact center and say I'm still on assigned heading and then they always go, oh, I thought you were direct, cleared direct to Birmingham. I say thanks and go direct.
My confusion is clearance was as filed which was KBTR ewa Kbhm but assigned heading being 4 degrees off over a 2 hour period actually puts me a good ways away. Why do they say as filed and then give vectors not as filed? Wouldn't it be easier to just give clearance as cleared to BHM via radar vectors and leave the old as filed off? Or is the as filed just there incase of radio communications loss?