Going around....
Sunday, July 13, 2014
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5 comments:
11 kt tailwind? Were they nuts (BOS, not LH)? No wonder he went around.
In all fairness, at ORD, the city was the one to call the shots on runway configuration. The same may be true at Logan. They (the city) tend not to be quite as responsive to runway conditions as the guys in the cab are.
And by the way, go arounds are not that uncommon. Sometimes it's initiated by the pilot (as this one seemed to be), other times the controller calls it. Reasons for that may be the preceding airplane doesn't clear the runway quick enough, the preceding airplane slows down too much on final causing the gap to close, an aborted takeoff on a crosssing runway, external exigencies such as a flock of birds or wildlife on the runway.
LRod
ZJX, ORD, ZAU retired
+1 on Lrod, but it would take an hour to change runways... And those ARE much quieter than the original powerplants! :-)
Don't know about an hour, DFW switches flow with a 10-15 minutes hold on inbounds and departures are paused less. We hold'em, they dry up the ones flying while launching the remaining ones at the hold pads, they taxi new push-backs to the other hold pads and we start sending them in landing the other way.
Heck, IAH changed flows 5 times in a 6 hour period last week...and under the new procedures we have to issue flow specific STAR's!
You want real fun, watch DFW in a "northwest flow" (strong winds from the NW, so they can only use the two diagonals) IFR. Sometimes they have to use 31L by having the aircraft fly and ILS to 18R and switch to 31L on breakout. Nothing quite like seeing a heavy pop out of the clouds almost over the International Parkway toll plaza and roll left to try and land.
I've been in both the cab and the TRACON at ORD during runway changes. It's an amazing bit of coordination and planning. I can't begin to explain it in complete detail because I wasn't there long enough to learn it all, but here are some things to think about and which may capture the flavor of it:
•Outbound Ground—the planes that have already started toward the active departure runway will mostly have to continue to that runway. Some will get rerouted to the new departure runway. Then new calls for clearance will start to be dispatched via the configuration route for the new runways.
•Inbound Ground—not near so much impact except unlike smaller airports, ground controls at ORD were nearly sterile from each other. During runway changes, there's a lot of coordination between the two ground controllers (and outbound ground is already the toughest position in the cab).
•Local (the controller who clears 'em to land and clears 'em for takeoff) has it a little easier. Basically they take all the arrivals as the show up, land 'em, and give them over to Ground. The departures have been spotted on the old active already, so they just continue to launch what are already staged there. They do have to be cognizant of the "dump zones" (where the vector men can descend arrivals) and honor them by the departure headings they assign.
•Arrivals—there are two arrival controls or vector men (sorry, there are women, too). They'll be advised who the last permitted arrival will be on the current runway (coordinated between the TRACON supervisor and the cab supervisor), will continue clearing airplanes for the approach, but will begin the sequence of the rest of the arrivals for the new runway(s). This is a matter of exquisite timing.
•Departures—Adjustments will be made, mostly as the last of the departures from the old configuration get off, as the "safe" areas that Departure "owns" change as vector men can start descending arrivals for the new runway(s) in a different area. This usually means climbs above the initial departure altitude (5,000') are delayed a bit, but Departure also needs to know where the first inbounds for the first runway are they can protect the new "dump zones" as the changeover of active runway takes place.
•The Center—the departure sectors at the center likely won't notice the difference, but the arrival sectors may be asked for further speed reductions than might be normal for the old configuration—going from "ten and run" (10,000' and 300 knots, for example) for the arrival fix on the off end of the runway, to 210 kts, 180 kts, or even a couple of turns in the hold at the arrival fix. That, in turn backs up to the feeder fixes (high altitude, usually) who may have to slow their rush to 250 kts thirty or forty miles sooner than they had been.
There's more, but it's a sublime exercise to witness, and I doubt that all the nuances could be appreciated by a non controller.
LRod
ZJX, ORD, ZAU retired
LRod, DFW has simplified the process a bit, bUt they also anticipate changes with the weather guys and a chart. They shut the door to ZFW and have the center hold. All aircraft inside the cornerpost continue to the old arrival runway, all aircraft in the departure line stay there and go as able. After the last departure is determined, easier since DFW has dedicated arrival/departure runways, the tower advises TRACON of the estimated time and TRACON advises the Center when to resume arrivals, a little before the last departure gets off. After the last arrival is down and the last departure is gone, operations fully resume in the opposite direction.
At the Center, we have the holding stacks to clear, and the departure sectors have to recoordinate the prearranged coordination airspace for the new direction. The coordination call is made as soon as we see a departure in the new direction. The whole process is about a 15 minute evolution these days. The average arrival hold is about 10 minutes.
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