It is the pilot's responsibility to know if he is flying in controlled/uncontrolled airspace. FL's are never part of uncontrolled airspace. If he is flying in controlled airspace and hopefully qualified to do so then he is given either and altitude to fly or a FL.vololiberista

We don't have controlled or uncontrolled airspace in the USA anymore. It's just either Class, A, B, C, D, E or G. Each has its own set of requirements about whether or not communications is required to fly within it. What was formerlly known as "controlled airspace" here in the USA is now Class E and is the majority of airspace below 18,000 here. And no communications with ATC is required within it then or now. So if the majority of your airspace is Class A or B above the TA where all aircraft are required to be in communications with ATC, then I can understand how a scheme like that can work. Otherwise, I still don't.

That's not the confusing part. What about a pilot flying within the QNE area who is not talking with ATC? How would he know whether FL025 is there or not?

He wouldn't but doesn't need to know. He will set 1013 and fly at whatever FL he chooses in exactly the same way he would fly at whatever altitude he choses if below the TA. If the pilot's not talking with ATC he's not being controlled and can chose his own altitude/FL.

We don't have controlled or uncontrolled airspace in the USA anymore. It's just either Class, A, B, C, D, E or G. Each has its own set of requirements about whether or not communications is required to fly within it. What was formerlly known as "controlled airspace" here in the USA is now Class E and is the majority of airspace below 18,000 here. And no communications with ATC is required within it then or now. So if the majority of your airspace is Class A or B above the TA where all aircraft are required to be in communications with ATC, then I can understand how a scheme like that can work. Otherwise, I still don't.

I believe Class G is still referred to as "uncontrolled" airspace...;)Regards,Scott

I believe Class G is still referred to as "uncontrolled" airspace...;)Regards,Scott

As a descriptive category, sure. But many years ago, we did actually have "Uncontrolled" airspace in the regulations but it was renamed Class G.

He wouldn't but doesn't need to know. He will set 1013 and fly at whatever FL he chooses in exactly the same way he would fly at whatever altitude he choses if below the TA. If the pilot's not talking with ATC he's not being controlled and can chose his own altitude/FL.

I accept that. It just seems peculiar that they would allow two airplanes in the vicinity of each other, both indicating 2,500' on their altimeters at different actual altitudes, and maybe not even realizing that one might be descending or climbing through an altitude that is supposed to be an occupiable cruising altitude. But I suppose that's not really all that different then when we pass through 18,000 on the way up or down and resetting our altimeter and then seeing what we are really at within the space that we are entering.