The holder of a flight engineer type rating is authorised to exercise the privileges of the rating in an aircraft model covered by the rating only if:
(a) within the previous 24 months, the holder has:
(i) exercised the privileges of the rating in the aircraft model; or
(ii) passed the flight test for the rating in the aircraft model; or
(iii) successfully completed a flight review in the aircraft model; or
(iv) if differences training is required by an instrument under regulation 61.055 or 61.060 for the aircraft model--completed the differences training; or
(i) the holder is successfully participating in an operator's training and checking system for an operation in the aircraft model; and
(ii) the operator holds an approval under regulation 61.040 for the system for this regulation and operations in aircraft of that model.