What transponder code should an IFR aircraft use after canceling their IFR flight plan?

When an IFR aircraft cancels their IFR flight plan, the appropriate transponder code to use is 1200, which designates a VFR (Visual Flight Rules) operation. After cancellation, the aircraft transitions from IFR to VFR, and switching to this code indicates that the flight is now operating under visual rules, allowing for more flexibility in flight operations.

Other codes serve different purposes; for instance, 7600 is used for a radio failure, indicating that the aircraft has lost its communication capabilities. The code 7700 is reserved for emergencies and signals that the aircraft is in distress. Code 1255 is not a standard transponder code recognized for normal operations. Thus, using 1200 is the correct procedure following the cancellation of an IFR flight plan.