Question For Arrival Controllers

[Dave T]

Here is a situation that happens to me quite often in several larger cities but lets use Calgary as an example. Coming in on the RNAV STAR's usually the waypoint that brings you into the downwind will have a restriction of say 7500 or above. You are on the star cleared to 5000 but are still required to cross the point at 7500 unless the controller waives it. It's really busy so it's tough to get in to ask if you can disregard the restriction. Then suddenly the controller says turn this heading plan the visual. Of course you were trying to respect the restriction and now you're chopping and dropping trying to get down and slowed down for the tight turn to final you're about to get.

My question is why is this in the arrivals when it's not in the non RNAV arrivals. I always thought the RNAV arrivals were meant to make things faster and easier for both pilots and controllers. I guess if there is a reason for them I'd like the controller to cancel the restriction with the clearance or keep us in the loop with his plan so that we can set ourselves up.
I fly a turbo prop and can usually make things work but I always find myself in that guessing game of what he is going to want us to do.

[parrot_head]

I think the reason for the difference between RNAV STARS and the conventional STARS as far as crossing restrictions goes is the equipment used to fly them. The RNAV STARS were designed to let the aircaft fly the arrival without any input from the controller (traffic permitting). The flight crew can load the arrival in the FMS and the aircraft is able to plan an uninterrupted descent based on any published altitude and speed restrictions. When the conventional STARS were designed, we didn't have this level of automation and we just relied on ATC to keep us at a safe altitude and vector us to final. As for jamming guys off the STARS to tighten up the circuit, I have given up trying. If an aircraft has been setup to join final at 6000' then they will be downwind around 8000' and there is no way you are getting that aircraft to descend fast enough to get them in tight. I've tried...and failed at this enough that I don't even bother any more. Most aircraft will stay on the RNAV STARS even after being cleared for a unrestricted visual approach. If I plan on keeping an aircraft tight I will first ask them if they are able to join a 3,4,5 mile final etc. I'll then put the aircraft on vectors which automatically cancels any STAR restrictions and then keep on eye on things to make sure they get down. The props are easier to work with and usually get the hint when you clear them to the FAF that they are expected to get down in time to join a tight final.

But you're right Dave T, it's easier for all of us if you know what the plan is so you can set up your aircraft accordingly or let us know if you don't think the plan will work. I have no problem with guys telling me that they won't be able to get down it time or can't accept a tighter approach, just let me know and I can just change things up a bit.