When may IFR be cancelled at an uncontrolled airport?

The cancellation of IFR (Instrument Flight Rules) at an uncontrolled airport is appropriate when a pilot has established visual reference with the landing surface. This means that once the pilot can see the airport environment, they can transition from flying under IFR to VFR (Visual Flight Rules), allowing for more flexibility in operations since the pilot can visually navigate to the airport rather than relying solely on instruments.

Visual reference indicates that the pilot is capable of seeing and understanding their surroundings, and that they can safely carry out the landing without the assistance of instrument guidance. This condition ensures that the pilot has enough situational awareness to navigate safely to the runway.

While there are other circumstances in which IFR may be cancelled (such as when instructed by air traffic control or upon reaching cruising altitude), they do not necessarily pertain to the requirement of visual references which provide the visual cues necessary for a safe landing in an uncontrolled airport environment. Therefore, the ability to see the landing surface is the key factor for canceling IFR under these conditions.