Trickijedi From United States of America, joined May 2001, 3266 posts, RR: 4 Posted (14 years 10 months 1 week 2 days ago) and read 13039 times:
I'm not even sure if I'm saying it right but, what does "metering" mean?
I was sitting in a United aircraft waiting for pushback while listening to ground communications. And then I heard pilots say something like, "United 61 (flight number is made up) metering." Then ground would respond with, "Roger, metering, United 61..."
What does this communication mean?
Its better to be on the ground wishing you were in the air than be in the air wishing you were on the ground. Fly safe!
Iainhol From , joined Dec 1969, posts, RR:
Reply 1, posted (14 years 10 months 1 week 1 day 22 hours ago) and read 13006 times:
When ground is busy they tell aircrafts to contact metering (where the aircraft gives there first call; who they are where they are and what they want) they do this so there are not a lot of aircraft contacting ground all at the same time. When ground can handle them metering will hand them off.
AM From Mexico, joined Oct 1999, 600 posts, RR: 2
Reply 3, posted (14 years 10 months 1 week 22 hours ago) and read 12944 times:
I have Trickijedi's same doubt. I was in O'Hare last week, scanning ATC frequencies. I noticed that every departing aircraft contacted metering, but only saying callsign. Metering would then assign a runway, and instruct the aircraft to monitor (not contact) ground, which then gave taxi-to-runway instructions. My guess is that metering keeps track of each flight's taxi-out time, so ground nows exactly when to contact them.
I never heard in any of the 2 frequencies a request for pushback clearance, so I haven't been able to figure out where this is done in airports with metering.
Also, I'm not sure if metering is the one who initially assigns the runway.
"... for there you have been and there you will long to return."
METERING- A method of time-regulating arrival traffic flow into a terminal area so as not to exceed a predetermined terminal acceptance rate.
Note that at the AIM site above, there are several other metering-related definitions.
In a general sense, the concept of metering aircraft is not unlike the concept whereby some freeway entrance ramps have traffic lights that tell you when to enter the stream of (heavy) traffic. In the case of aircraft, a destination airport's acceptance rate is often affected by weather and related operational restrictions, which, back to auto anologies, is akin to closing 1 or 2 (or more) lanes of a 3 or 4 lane freeway. The big difference between the two transportation modes is that aircraft can NEVER be allowed to get "bumper-to-bumper" in the air, thus traffic flow must be regulated to keep it flowing while keeping it properly separated.
In your ORD scenario, some of the destinations served by airlines there were most probably suffering from reductions in their acceptance rates, and traffic to those destination was being delayed to await their "green light" to enter the airspace system. The ATC metering position essentially keeps track of when (as dictated by FAA ATCSCC in Washington) various aircraft will be allowed to takeoff.
Flights destined to LAX, SFO, and SEA commonly experience these types delays should cloud ceilings and/or visibilities there slow the flow of arrivals into the airport (by precluding the use of visual approaches in favor of ILS approaches). Flights destined to these, and just about any other airport can also (and unfortunatly, do also) occur should thunderstorms be slowing arrivals at the destination airport, or even the route between the departure and destination airports.