Originally Posted by
Red Four
It looks to me that in this case it is for airspace containment purposes; the granted CTA's to EGLF would be as small as feasible, consistent with the purpose for the CAS is in place in the first place. This reduces the impact on nearby aerodromes/aviation users.
The FAF being at the points where they are ensure that aircraft on the ILS will remain 500ft above the base of CAS of the various stepped down airspaces, whilst following the ILS profile down into the CTR.
Not obviously related to obstacles, as EGLF SMAC chart still has lower levels available (in theory), say if one was arriving/transitting IFR from outside CAS.
You also have to remember that aircraft must be vectored to enable them to establish and stabilise on the localiser a MINIMUM of 2nm before glidepath intercept and aircraft must be vectored not less than 2nm inside the boundary of CAS
I originally designed the Farnborough procedures to use alt 1,900ft as the 'platform' altitude but for some reason since I retired, the've been using a higher altitude; it was 2,400ft before CAS but what they use now I don't know.