Definition
A precision instrument approach and landing operation with a decision height (DH) not lower than 200 feet above the touchdown zone elevation, and with either a visibility not less than 1/2 statute mile (2,400 feet) or a runway visual range (RVR) not less than 1,800 feet (with touchdown zone and centerline lighting, RVR may be reduced to 1,800 feet; without these aids, 2,400 feet RVR is required). Category I (CAT I) is the least demanding category of precision approach and is conducted using ILS, GLS, or other approved precision approach systems.
Plain English
An instrument approach where the pilot must be able to see the runway by 200 feet above the ground and visibility must be at least about half a mile. It's the standard low-weather precision approach most pilots fly.
Context Anchor
Seen in instrument approach, landing minimums, ILS, GLS, and other precision approach discussions.
Derivation
The term "Category" reflects ICAO's tiered classification system, where Category I, II, and III represent progressively lower weather minima allowed for precision approaches. CAT I is the highest (least restrictive) tier, requiring the most weather. Lower categories permit landings in worse visibility but demand more capable aircraft, crew training, and ground equipment.
Why Pilots Care
Sets the legal weather minimums for conducting a precision approach and completing the landing.
Intuition Check
Do not read “Category I” as a general difficulty rating. Here it is a specific FAA landing category with defined height and visibility limits.
Example Sentence 1
The forecast calls for a 300-foot ceiling and 1 mile visibility, so we're well above CAT I minima for the ILS approach.
Example Sentence 2
Aircraft must be equipped and certified for Category I operations before the crew can accept those minima.