Aircraft Flight Operation Regulations Article 165

An operator may not schedule any pilot to serve as pilot of an aircraft, unless within the preceding 12 calendar months that pilot has passed a line check in which he has satisfactorily performed the duties and responsibilities of a pilot in the types of aircraft he is to fly.The line check aforementioned in the preceding paragraph shall be conducted by the check airman.A line check given to the pilot within a period of one month before or after the month in which the check is due, is considered to be given on the month due for the determination of next due date for line check.