When is IFR primarily used in aviation?

The use of IFR (Instrument Flight Rules) is primarily associated with flight operations conducted in conditions where visibility is inadequate for VFR (Visual Flight Rules) flight. This includes situations such as cloudy weather, fog, rain, or any other atmospheric conditions that limit a pilot's ability to navigate and control the aircraft by visual references outside the cockpit.

In IFR, pilots rely on instruments located in the cockpit to fly the aircraft, which allows them to operate safely in these challenging conditions. The approach to flight under IFR helps ensure safety by utilizing air traffic control and navigation systems designed to assist in maintaining separation from other aircraft and safely navigating through the skies, regardless of the weather conditions.

In contrast to this, VFR is utilized when weather conditions are clear enough for pilots to navigate visually, which makes IFR unnecessary in those circumstances. Furthermore, routine maintenance is a procedure conducted regardless of flying conditions and is unrelated to flight rules directly. Night flying can be conducted under VFR or IFR, depending on visibility and other factors; therefore, it does not exclusively define when IFR is used.