Cross fix at xx:xxZ

[2ndGenPSA]

This is a first!
I heard Atlanta Center clear a flight inbound to CLT to cross a fix at a specific time. With the new time-based metering, this sounded appropriate enough. The crew's reply to the controller was less than confident, but they accepted the clearance without query. After a few minutes, the controller asked the flight if they had time for a question (haha!). He asked the flight if the clearance that HE had issued gave the flight the authority to deviate from their course to the fix, and to adjust their speed. The flight replied that they were wondering the same thing, that they had reduced their speed as much as possible, and that they would need delay vectors to meet the crossing time restriction. The controller then cleared the flight for 30 degree turns left and right of course.

Uhhhhhh, I have a little issue with a controller not knowing what his clearance meant! Is ATC experimenting with TBM and placing more responsibility on the crews to meet fix arrival times? Was this controller just trying his own thing because he's tired of vectoring planes to meet the times? Is this type of clearance in the handbook?

Interesting.

 

[BillJBrake]

it seems like in the Northeast, with EWR metering, must crews are un-capable or don't fully understand the restriction and so most controllers have abandoned the concept and have gone back to vectoring and speed restrictions.

Would be nifty if most pilots would work with it, we could set the FMS with a time and autothrottles or speed inputs could get hte plane there at the precise time, vs the controller guessing with speed restrictions.

 

[BillJBrake]

also, what do you mean by TBM? metering is metering.

 

[pilothouston123]

It happened to me in the gulfstream going into HOU. Looked at the FMS and slowed down a bit. No big deal. Then right after we crossed the fix, we got max forward speed. Then about 20 miles from the airport they turned the airport around and we landed with min fuel...
All in a days work.

 

[2ndGenPSA]

My understanding is that TIME based metering is relatively new. The controllers sure act like it is judging by their grumblings when the computer spits out a revised time for our A/C to cross a fix. I think metering used to be based first on volume, then on distance spacing between A/C. Now the system assigns a time for an A/C to cross a fix.

Anyhow, the real point of my question is this: the controller didn't know how much authority his clearance gave us, in terms of speed and delay vectors. Speed is intuitive. But when speed alone won't be enough to cross the fix at the specified time, is the A/C authorized to fly its own delay vectors?

 

[2ndGenPSA]

TBM does exist!
4 Operational Improvement: Time Based Metering Using RNAV and RNP Route Assignments
from
http://nas-architecture.faa.gov/nas/service/full_text.cfm?SVHID=104123

Oh god, I have a day off and I'm on an FAA website. I'm outta here! Time for green beer!

 

[CA1900]

My understanding is that TIME based metering is relatively new.

Maybe in some parts... I used to frequently get "Cross WOONS at XX:XX" enroute to BOS when I was going in there pretty regularly, and that was 10 years ago.

 

[dispatchguy]

Maybe in some parts... I used to frequently get "Cross WOONS at XX:XX" enroute to BOS when I was going in there pretty regularly, and that was 10 years ago.

Were you flying an FMS airplane, or was the FMS between the pilots ears like a DC9?

 

[SpeedRestricted]

I was once cleared to cross a fix at a specific time if unable hold at the fix as to depart it at that time. In that particular case I was specifically given the hold instructions, I don't recall where it was at.

 

[westwind driver]

Flew into Calgary back in 2005, was told to cross the arrival fix at a specific time. What did we do? Entered the hold at the arrival fix as depicted on the chart, flew a few turns, flew one half leg, turned inbound and crossed the fix at the specific time. We were so close in to the fix that slowing down would not have worked. Truth be told I cant really remember if we were told to enter the hold and then cross the fix at the specific time.

I think this was almost exactly like SpeedRestricted's experience.

Others flying into Calgary may help shed some light on this.

As for the FAA, TBM looks like it is gonna take some time to get everyone comfortable with the operations.