This is not 'my' graphic, but from the FAA RECAT program currently being used.
If you look at the diagram, there is an asterisk...at the lower left, the asterisk is explained. With the FAA, 2.5nm MRS requires a waiver.
With the FAA RECAT, there is no wake spacing allowed lower than the MRS value.
Note the aircraft diagram included...a B747 following the A306...2.5nm minimum wake turbulence separation.
Last edited by FlightPathOBN; 20th Dec 2012 at 19:24.