CGB
The use of the permissive verb "should" is common to the MAA documentation and EASA's design specifications (as "soft law" allowing proportionate and appropriate application of the regulation). You are right in saying that Defence Estates, or Defence Infrastructure Organaisation, have adopted CAP 168 almost verbatim; intermingled with ICAO standards and recommended practices, (with some obvious differences where there is no direct civil equivalent), although they quote ICAO Annex 14 as the source in the AIP and the Military Aviation Aerodromes Standards and Criteria document (JSP 554 replacement). That said, it may be the case that it is not possible or feasible to attain the aforementioned regulatory requirements - local topography could be an inhibiting factor, lack of adequate funding another. There may be no perceived need to comply - as in Roland's analogy with Nimrod at Gibraltar; ain't broke, don't fix it (which would probably get a frosty reception from the man in the grey wig).
Whereas ICAO uses the prescriptive "shall" in standards, but not in recommended practices, CAP 168 uses "should", but states at the outset that "should" means "shall". EASA uses "should throughtout the aerodrome design specifications to allow flexibility for all member states.
Every aerodrome should have an Aerodrome Manual as their exposition on technical administration, operational procedures, aerodrome characteristics, visual aids, RFFS and much more, and it is the prime safety assurance document for that aerodrome. As each aerodrome is in some way different from all others, the AD Manual is a discrete document for that particular location, and as such is the master document. The IAIP contains higher level regulatory material (AD.1) derived from the ANO and CAA, but the specific aerodrome entry (AD.2) is compiled from data in the aerodrome's manual.
Hope that's been of some help.
Mister B
Last edited by HTB; 4th Jun 2014 at 11:05.
Reason: korrecting some spilling orrers wot I did nut splot befour