IFR separation is required regardless of weather (VMC or IMC).

• A. IFR separation is required regardless of weather (VMC or IMC).
• B. IFR separation is required only in IMC.
• C. IFR separation is required only in VMC.
• D. IFR separation is never required.

Answer: (A)

Separation for IFR flights is provided by air traffic control regardless of weather because IFR operations rely on ATC to keep instrument-rated aircraft safely apart in controlled airspace, irrespective of visibility.

In IMC, visibility is limited, so pilots cannot rely on sight to maintain separation; ATC must provide the necessary spacing to prevent conflicts and ensure safe routing and altitude management. In VMC, pilots can use see-and-avoid, but IFR traffic is still managed by ATC to maintain orderly flow and prevent collisions, especially in busy airspace or when radar vectors are used.

So the requirement to separate IFR aircraft does not depend on whether the weather is good or bad; it remains in effect in both conditions. The other options imply weather changes the requirement, which isn’t correct.