Wheels up time

Maximilian_Jenius

Maximilian_Jenius

Super User
On the way to NJC05 this year I happened to miss my flight out of PHX direct to LAS.
I was rebooked stand-by to SAN. The plane was scheduled to leave at 4:10pm. SWA only having 137 seats on there 737-700's and the popularity of Vegas on a Friday led to a full plane.

The pilot came on intercom at 4:15 maybe 4:17-ish and asked that everybody find a seat and quickly because we had two mins. to leave the gate or we would miss our "wheels up time."
So a stampede occured and everybody safely found a seat and we pushed back in time. But when we got to the end of the runway we were put in the "penalty box."

The pilot came on the intercom and said that we missed our slot and we would have to wait for them to fit us in due to flow issues. Well we sat there for over an hour.

My question is...what is "wheels-up time?" Also why do you sometimes see planes already at the departure end of the runway making room for other planes to cut in front of them.
I was listening to the PHX scanner the other day and WN flight cut to the front of the takeoff que (with towers permission) because he was in danger of losing his wheels up time.

-Matthew
 
I heard that planes flying into heavy traffic airports, such as LAS are put into a flow controll. ATC knows how many planes are going to a particular destination so assigning them a wheels up time based on flight plan info keeps them in a smooth flow into the B airport. In theory that is. Miss your spot and you are invading someone elses time. I see it all the time with planes going to Chicago out of here in Grand Rapids.
 
its essentially a clearance that isnt valid yet, with a void time. We get them due to ground delay programs, ground stops, traffic saturation, weather, etc.

A good example is say some field in CAVU can accept 80 (fictional numbers) arrivals per hour, but if the wx goes down to 200&1/2 it can only accept 40 arrivals an hour, and there are 60 planes scheduled to arrive that hour. ATC will then coordinate to change departure times so that traffic wont back up at the airport due to the reduced capacity (essentially holding on the ground vs in the air). The modified times for each airplane to leave are thier wheels up time.

If the traffic flow warrants it, you may have a window to get airborne, or have to wait a while for a new window, which sounds like what happened to you. That stems from enroute traffic spacing, where some airport may want its arrivals spaced 20 or 40 miles apart, and rather than slow everyone down further so you can catch up and get into your slot, they give it someone else or speed people up to close the gap you would have fit into. And as an example ive been given vectors out of chicago to get 20 mile spacing into houston, the effects can cover large distances.
 
Maximillian_Jenius said:
My question is...what is "wheels-up time?" Also why do you sometimes see planes already at the departure end of the runway making room for other planes to cut in front of them.
I was listening to the PHX scanner the other day and WN flight cut to the front of the takeoff que (with towers permission) because he was in danger of losing his wheels up time.

-Matthew
Click to expand...

The last two guys pretty much covered the second part of your question. However, "wheels-up time" is fancy pilot speak for takeoff time. For those pilots who fly retracts, it's the time when you get to put the wheels in the wells!
 
Planes get to cut in or queue jump if they are in the departure queue and their take-off slot or wheels-up time window is about to expire, then the tower will slide them in, to get them off the ground. This is common across Europe and the US where there is so much congestion in the airways, that a careful calculation of load is applied to each sector the plane will fly through, to ensure there is space enroute as well as a landing slot at the destination airport. I remember a gate-hold delay of 1 hour when I was flying Air Canada from LHR to YVR - reason saturated UK airspace between London and Glasgow. The fuel to run the APU sitting on the ground is a lot cheaper than flying in circles at 35,000ft waiting for the next sector to have space to take you. There is a further problem on LAS-PHX - they are relatively close together, compared to other destinations served from those airfields, so if you miss your slot, the rest of the slots near it are already taken by planes that have been in the air for hours already, so you will get a long delay, but if you are going JFK-LAX and there are no WX delays enroute then missing a slot, may not be such a problem, because most arrivals into LAX will be travelling from closer than JFK, so they will leave after you. It is called Flow Control and somewhere in the US, I think around Washington is facility that co-ordinates all these take-off slots, whilst monitoring the nation's weather from an aviation viewpoint. It is they that decide whether JFK-LAX will overfly Chicago or somewhere further south depending on route loading and weather.
 
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