What should a pilot do before transitioning from VFR to IFR on a composite flight plan?

Before transitioning from Visual Flight Rules (VFR) to Instrument Flight Rules (IFR) on a composite flight plan, the appropriate action for a pilot is to contact the nearest Flight Service Station (FSS) to close the VFR portion of the flight and request an IFR clearance from Air Traffic Control (ATC).

This process is important to ensure that the pilot formally concludes the VFR segment of the flight, which maintains accurate records and facilitates air traffic management. By doing so, the pilot ensures that ATC is aware of the transition to IFR conditions and can provide necessary services and separation from other traffic. Requesting an ATC clearance is essential as it gives the pilot authorization to operate under IFR, which includes navigation and procedural protocols that differ from VFR.

The other options do not appropriately reflect the necessary actions required for a safe and compliance-focused transition from VFR to IFR. For instance, simply notifying ATC after reaching a certain altitude does not cover the requirement to officially close the VFR portion and receive an IFR clearance. Filing a new flight plan with ATC is unnecessary since the transition to IFR can be accomplished with the existing composite flight plan by making the correct notification. Additionally, switching the transponder code to 1200 is