(a) An aircraft shall be deemed to be in flight from the time that all external doors are closed after all boarding is completed until any such door is opened for disembarkation. However, in the case of emergency landing, the aircraft shall be considered to be in a state of flight until the authorized authority takes responsibility for the aircraft and the passengers and cargo in it.
(b) An aircraft shall be deemed to be in service for twenty-four hours after landing from the commencement of pre-flight preparations by ground personnel or crew for a particular flight. In any case, the period of operation in such service shall be deemed to continue throughout the flight period as per clause (a).