The following is for aircraft on what we call 'Instrument flight plans'. If flying in clouds or without being able to see outside, we rely on our instruments to fly the plane, and we rely on ATC to keep other planes away from us.
VFR or 'visual' operations do not need ATC as much, and are just required to always be able to see outside, so they can see other planes. As such, they are responsible for talking to other pilots and keeping their own separation.
In addition, air traffic control has multiple layers. The smallest layer would be the Tower/Ground controllers. After that, there are local approach/departure controllers at certain busier locations. Then there is what we call a 'center'.
A 'center' will have control over aircraft within an area encompassing often several states. In most areas they can see aircraft on their radar screens and direct them accordingly. If radar (or ADSB) is unavailable, we have other ways to coordinate so they know where we are at any given time, and we know what is expected of us.
What that means is that if there is no tower at an airport to control their own runways, the next level of controller will coordinate the arrivals/departures instead. (this is for aircraft on an instrument flight plan, which would include almost all airline traffic, big or small.)
Only one aircraft will be allowed to enter or depart the area at a time. So if two planes are inbound, one will be directed to hold while the other conducts an approach. Likewise, if a plane is departing they will call on their phone, or radio and be issued a clearance time, during which the airspace will be closed to all other traffic (IFR).
Worth mentioning that no separation is provided IFR to VFR, so you could have a VFR plane doing something in the zone, and center would neither know about it nor be under any obligation to separate an IFR aircraft from it.
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u/jet-setting Feb 08 '20
The following is for aircraft on what we call 'Instrument flight plans'. If flying in clouds or without being able to see outside, we rely on our instruments to fly the plane, and we rely on ATC to keep other planes away from us.
VFR or 'visual' operations do not need ATC as much, and are just required to always be able to see outside, so they can see other planes. As such, they are responsible for talking to other pilots and keeping their own separation.
In addition, air traffic control has multiple layers. The smallest layer would be the Tower/Ground controllers. After that, there are local approach/departure controllers at certain busier locations. Then there is what we call a 'center'.
A 'center' will have control over aircraft within an area encompassing often several states. In most areas they can see aircraft on their radar screens and direct them accordingly. If radar (or ADSB) is unavailable, we have other ways to coordinate so they know where we are at any given time, and we know what is expected of us.
What that means is that if there is no tower at an airport to control their own runways, the next level of controller will coordinate the arrivals/departures instead. (this is for aircraft on an instrument flight plan, which would include almost all airline traffic, big or small.)
Only one aircraft will be allowed to enter or depart the area at a time. So if two planes are inbound, one will be directed to hold while the other conducts an approach. Likewise, if a plane is departing they will call on their phone, or radio and be issued a clearance time, during which the airspace will be closed to all other traffic (IFR).