Originally Posted by
DaveReidUK
Yes, but that assumes time-based separation, which doesn't account for what the OP was seeing 30 years ago.
TBS is only applied between vortex pairs so it isn’t applied between mediums Dave. (Not yet anyway!)
30 years ago the minimum spacing between mediums was 2.5nm now it’s (not less than) 2.5nm, effectively the same but there needs to be a strong headwind to employ 2.5 nm spacing.