A parameter that prevents an improvement into an already organised departure sequence. It may be adjusted at any time depending on the local aerodrome traffic situation and may vary during the day. The TIS parameter is not relevant when ATC has sent an REA message for a flight. The TIS makes sure that a CTOT improvement cannot be sent at short notice as the aerodrome requires some time to introduce an aircraft in the departure sequence (the new CTOT cannot be earlier than clock time + TIS + taxi time).