Aircraft Flight Operation Regulations Article 42

After the commencement of a flight duty, no prolongation of a flight duty period is allowed unless the flight crew has rested for more than 3 hours in a proper rest place arranged by the operator. On occasions of flight delay, the flight duty period may be extended by half of such rest period; in no circumstances should the total period of the extended flight duty period plus the rest period exceed 24 consecutive hours.If a flight is dispatched in accordance with the paragraph 2 of Article 38 with multiple flight crew, and in-flight diversion occurs due to an extraordinary event or circumstance beyond control (such as war, strike, riot, act of God, etc.), the pilot-in-command (PIC), after a thorough evaluation for the safety of the flight, may extend the flight duty period by two hours without the restriction as prescribed in the preceding paragraph.