Departure separation (time based)

I’ve noticed that there is often little to no time separation between departing traffic which becomes a problem with aircraft departing at different speeds. should ATC try impose the necessary separation between departing traffic. for example;
-Departure …2 minutes
-Displaced threshold departure …2 minutes
-Intermediate departure …3 minutes
-Arrival …2 minutes (3 minutes for light after heavy)


On the Expert server the controllers do try to space out planes properly by distance. It really helps when pilots file a flight plan so the controller knows around where they will be heading.


ah yes of course i agree the flight plans are a must as atc can anticipate the departure route! just noticed this a couple days ago departing KLAX and i had an MD-11 coming up behind me almost just as i reached Vr

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I use a general rule of clearance for takeoff when the prior aircraft reaches the end of the other threshold unless there is the extreme outlier if a 172 in front of a Cessna, then there would probably be like 3 minutes of separation.


from my atpl air law studies the correct separation is as stated above :) that at least minimises the risk of conflicting aircraft on departure :)


In some cases ATC is aware of the differences in aircraft speed. For example a A380 taking off behind a Cessna will probably catch him up within a minute. If a proper time separation is maintained, they’ll both have a great flight.

Keep in mind that ATC tries to send the deps as soon as they can, especially when it’s busy. If it happens to you, try to keep a vertical separation when needed or just a safe distance at all. Not only ATC is responsible for a safe traffic flow but also the pilots. Think as an ATC during your flight :)


Little separation is often created when an aircraft departs and the following aircraft lines up on the runway and gets takeoff clearance as soon as the first aircraft is airborne. That‘s why I usually don‘t use LUAW for dep/dep. I hold them short and clear if the aircraft which is on takeoff roll has a speed of around 130kts. Until the following aircraft has lined up and started takeoff roll the aircraft ahead is already miles away, so they have enough spacing. (I only do this if aircrafts depart with around the same speed)


There’s different methods of separating aircraft. The one you’ve stated is non radar separation but we use radar in IF so you don’t need the applicable time separation but radar based separation instead.


Time-based separation is likely to only be implemented if wake turbulence was added. Other posters have touched on most of the reasons as to why we don’t bother with it at the moment.


We have unrealistic volumes. Waiting 3 minutes, no one would ever depart the FNF hub.


Rolling departures; that fixes everything. When the wheels never stop once they get going, it speeds up things a lot.

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ATC experts will know more about how to position airspace that does not need to worry because they are trained and according to procedures

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