Ah, High Performance Aeroplane...thanks for that, I should have looked myself. It's basically gunning exactly for this whole CPL/ATP on a 1900 type aircraft, ie. CPL's have not been tested on turbine theory, high alt/high speed flight etc.
Quote of the relevant bit:
Originally Posted by CAA!
2 High Performance Aeroplane (HPA) Training Course of additional theoretical
knowledge training for a class or type rating for high performance single-pilot
aeroplane and warbird type endorsements.
2.1 A number of aeroplanes certificated for single pilot operation have similar
performances, systems and navigation capabilities to those more usually
associated with multi-pilot types of aeroplanes, and regularly operate within the
same airspace. The level of knowledge required to operate safely in this
environment is not part of, or not included to the necessary depth of knowledge
in the training syllabi for the PPL, CPL or IR(A) but these licence holders may fly
as pilot-in-command of such aeroplanes.
SA CATS-FCL 61 CLASS & TYPE RATINGS Page TS 61.13 - 3
17 February 2008
2.2 The aim of the theoretical knowledge course is to provide the applicant with
sufficient knowledge of those aspects of the operation of aeroplanes capable of
operating at high speeds and altitudes, and the aircraft systems necessary for
such operation.
2.3 The holder of an ATPL(A) issued by a contracting state or a pass in the
theoretical knowledge examinations at ATPL(A) level is credited with meeting the
requirement of Regulation 61.13.4(3).
2.4 A pass in any theoretical knowledge subjects as part of the HPA course will not
be credited against meeting future theoretical examination requirements for issue
of a CPL(A), IR(A) or ATPL(A).
Most helpful, thank you Prop Pilot!
It also seems to clear up, to a degree, what the CAA are aiming for.