The Aircrew Regulation requirement for ZFTT is as follows:
FCL.730.A Specific requirements for pilots undertaking a zero flight time type rating (ZFTT) course — aeroplanes
(a) A pilot undertaking instruction at a ZFTT course shall have completed, on a multi-pilot turbo-jet aeroplane certificated to the standards of CS-25 or equivalent airworthiness code or on a multi-pilot turbo-prop aeroplane having a maximum certificated take-off mass of not less than 10 tonnes or a certificated passenger seating configuration of more than 19 passengers, at least:
(1) if an FFS qualified to level CG, C or interim C is used during the course, 1500 hours flight time or 250 route sectors;
(2) if an FFS qualified to level DG or D is used during the course, 500 hours flight time or 100 route sectors.
(b) When a pilot is changing from a turbo-prop to a turbo-jet aeroplane or from a turbo-jet to a turbo-prop aeroplane, additional simulator training shall be required.
It is possible that airlines may impose further restrictions on their ZFTT applicants.