How do RNAV STARs increase capacity?
I see a lot of claims by airports that the implementation of RNAV STARs enables them to handle more traffic.
Can some kind ATC soul explain to me how - at airports where 3nm separation is already in place - a change from vectoring aircraft to final approach via quite widely laterally-separated routes, to routing every aircraft along a single narrow RNAV route to final, can possibly increase the number of arrival movements?