My understanding of the Class E proposal around Aberdeen is that it stems from a limitation imposed upon ABZ ATC that means it is not allowed to vector traffic out of CAS and then back in again. Converting some of the Class F ADRs into Class E would mean that any IFR traffic arriving along the new Class E routes would then be constrained to staying inside CAS all the way, which would remove flexibility in vectoring and require increased spacing over that currently practised (because traffic arriving along the existing Class F can be vectored freely until it enters the CTR). The solution is to extend the CTR north and eastwards as Class E, which means that the IFR traffic will be able to be vectored without leaving CAS, avoiding the exit-reentry prohibition, while local VFR traffic will be able to carry on unaffected (Class E = no requirement for 2-way R/T or clearance when VFR).
It sounds like a bit of a bureaucrat's solution (why not just give ABZ ATC permission to vector out and in of CAS?) but it is the right choice of airspace class for the purpose. At the consultation meeting, some stakeholders tried variously to call for "mandatory R/T contact" for VFR traffic crossing the area, or even for "all speaking units to be treated as IFR traffic". The former proposal would result in a Class D extension in all but requirement for clearance, while the latter would either result in VFR traffic never calling up, or in the effective imposition of Class B rules, i.e. standard separation provided to VFR traffic. Seems like some will always push for bespoke local rules or seek to legislate for good airmanship - fortunately, this time, it seems like a plain, simple chunk of ICAO-compliance has been selected.
Last edited by Easy Street; 20th October 2013 at 12:06.