[dghlsakjg]

The training I got as a lowly ppl, was that a takeoff clearance meant that the runway was yours to do with as you pleased within reason. If the southwest crew needed to sit on the runway for a few moments getting setup they had permission to do it. Their job is to follow atc directions, which they absolutely did.

If the controller wanted you to do an immediate takeoff they normally make damn sure that you are able and you know the context. At least in my experience mixing it up with jet traffic at Boeing field.

Something like: “Southwest xxx cleared for immediate takeoff, you have a FedEx heavy on 3 mile final”

To the pilot that is saying: you can go, but you only have 90 seconds or so.

[cm2187]

But surely "within reason" includes some sort of timeout?

[dghlsakjg]

Kind of. It’s not unheard of for the plane to have issues on the runway. Flat tire, avionics settings, whatever. That causes you a delay on the runway, or to just have to sit there and close the runway

On a regular day the controller could see this, and ask what is going on. At a small GA airport with training ops the controller is likely used to people pulling out onto the runway and taking their god damn time. The FAA actually advises wait times of as long as 2 minutes for wake turbulence, and that’s something I’ve done. Just sit there on the end of a runway.

Things get a little different, in practice, at busy commercial airports, but the rules are the same.

[sgent]

Used to fly out of MEM in the co-pilot seat when it was still a hub for NWA. Usually, the small planes they lined up on an alternative runway, but occasionally wind direction / strength required using one of the two (now three) parallel runways.

More than once I remember a 747, 777 or A340 taking off and getting the call "cleared for immediate departure". The pilot I was with routinely would say something like "I'm not even taxing onto the runway for 2 minutes, then we can talk".

[cm2187]

Maybe I am thick but I am not sure I got your point. You mean he would wait 2min off the runway? Why, vortex created by larger planes?

[dghlsakjg]

Yeah. Turbulence from a large plane can affect small planes in really dangerous ways, and it can exist for up to 2 minutes.

So if a large plane has just used a runway, small planes will wait before taking off, whether that’s on the runway or off the side on a taxiway is up to the pilot and the tower controller.