A pilot may file a flight plan with ATS unit during flight, although the use of busy air traffic control channels for this purpose should be avoided. Details should be passed using the flight plan format.

During a flight a pilot may change from IFR to VFR flight.

When a pilot has expressed the intention to change from IFR to VFR flight, the ATS unit should pass to the pilot any available meteorological information which makes it likely that flight in VMC cannot be maintained.