What happens to IFR when the tower is open?

When the tower is open, IFR (Instrument Flight Rules) clearance does not require any action from the pilot to cancel it; instead, it automatically transitions to the appropriate clearance under the control of the air traffic control tower. When an airport has an operating control tower and the pilot is departing, the tower will typically provide IFR clearance to continue flying under instrument rules as required.

This automatic transition is essential for maintaining safe air traffic operations, as it enables pilots to shift between IFR and tower control smoothly without needing to take additional steps that might complicate communications or operations. In contrast, if a tower isn't open, pilots often need to cancel their IFR flight plans manually, as there is no control tower to maintain that oversight.