It's not just high traffic conditions. An airplane can seperate itself from nearby airplanes but it doesn't have the ability to take into account the whole system. A disabled aircraft on the runway at say LAX riplles thru out the whole NAS.

Why? (serious question)

I suspect the answer involves a sea of airplanes each of which needs the
other to do something (such as clear the airspace) before -it- can do
something (such as enter it), and this has to do with IFR separation
requirements, which is (one reason) why bad weather can tie airspace in
knots, where as in good weather traffic is more resiliant.

If all air traffic were VFR, would a disabled aircraft at LAX impact the
whole NAS?

Jose
--
Get high on gasoline: fly an airplane.
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