20.18.3
Instrumentation for flight under Visual Flight Rules
RPT aeroplanes and large charter aeroplanes
3.1 An aeroplane engaged in:
(a) a regular public transport operation (RPT); or
(b) a charter operation that has maximum take-off weight exceeding 5 700 kg — a charter operation;
The only other reference to "charter aeroplanes" (as opposed to helis etc) defines them as "engaged in a charter operation".
Subsection 3 appears before Subsection 10 (with no other specific reference), and so it could be argued sets a precedent for any latter definition of the same term.
No wonder law pays more than airwork.