Presently, sponsors of airspace base their design on standards which reflect a requirement for the operation of CAT without taking the impact on other airspace users into account. Some design elements which are no longer relevant to modern air operations are still included even though seldom ever used.  The FAS vision and FASIIG plans would see continuous climbs and descents but much airspace is designed to accommodate stop altitudes at low levels and low rates of climb reducing or eliminating benefits.  Some existing terminal airspace has a lower base than necessary for modern day CAT. Moreover, although traffic using London airports must expect significant circuitous routing in the TMA because of interactions with adjacent IFR operations, regional airports typically design their airspace to facilitate direct track routing ignoring the impact on adjacent VFR operations.

FASVIG would work with the CAA to review the way design rules are applied to take account of the limited airspace available and to balance the requirements of other airspace users at the design stage.