What does Instrument Meteorological Conditions (IMC) refer to?

Instrument Meteorological Conditions (IMC) refers specifically to conditions where aircraft operations must rely on instrument navigation due to poor visibility or weather conditions. This typically occurs in situations where pilots cannot maintain visual reference outside the cockpit, necessitating the use of the aircraft’s instruments to navigate, control altitude, and maintain situational awareness.

The correct answer emphasizes the necessity of navigating primarily using instrument references. In IMC, pilots are required to trust the aircraft's instruments for everything from altitude to heading since visual cues from the outside environment are not reliable or non-existent. This is a crucial skill for pilots, particularly in adverse weather situations where clouds, fog, rain, or snow can obscure vision.

The context of other options clarifies why they are not correct. Flying under visual flight rules relates to conditions where pilots can navigate using visual references, which contradicts the concept of IMC. Using visual references for navigation and flying during good weather conditions also do not accurately describe IMC, as both imply a reliance on outside visuals rather than the instruments inside the cockpit.