Multi-engined aeroplanes powered by turbo-prop engines with a max approved passenger seating configuration of more than 9 or a max take-off mass exceeding 5700kg and all multi-engined turbo-jet powered aeroplanes are class A.
The operating regulations for this class was covered as part of the JAR ATPL Aircraft Performance exam..
Checkout JAR OPS/section 1/subpart G (class A regs)
Hope this helps..