Instrument flight rules (IFR)

Instrument flight rules (IFR) are the rules and procedures for operating an aircraft primarily by reference to flight instruments and an instrument clearance. IFR operations require the applicable aircraft equipment, pilot qualifications, weather planning, communication, and compliance with the assigned clearance.

What it governs

An IFR flight follows an instrument flight plan and uses published procedures or clearances for departure, en route flight, arrival, and approach. Air traffic control separates IFR traffic according to the applicable rules and may assign headings, altitudes, fixes, routes, and approach instructions. A clearance authorizes the pilot to operate within the clearance; it does not remove the pilot's responsibility to verify the aircraft and flight remain suitable.

IFR is different from visual flight rules. The weather conditions may be visual or instrument at a particular moment, but the operating rules and clearance determine how the flight is conducted.

Example

A pilot files an IFR flight plan from one airport to another, receives a clearance containing a departure procedure, route, altitude, and destination instructions, then flies the clearance using the aircraft's approved instruments and navigation equipment. The pilot monitors the TAF and current observations throughout planning.

Why it matters

IFR procedures provide a structured way to operate when visual references are limited. They also involve workload, equipment, currency, alternate planning, and communication requirements that vary with the flight. A pilot must review the current procedure and NOTAM information before departure.

This glossary entry is not a substitute for the current regulations, clearance, aircraft manuals, or instrument procedure. See eCFR Title 14 and the FAA Aeronautical Information Manual for governing material.

Related terms and tools

• Visual flight rules
• TAF
• eCFR Title 14