Definition
Category II Instrument Landing System approaches are precision instrument approaches that allow a pilot to descend lower and land in worse visibility than a standard (CAT I) ILS approach. CAT II minimums typically permit a decision height as low as 100 feet above the touchdown zone and a runway visual range as low as 1,200 feet. Conducting a CAT II approach requires special authorization, additional pilot training, more capable aircraft equipment, and a runway with enhanced ground-based equipment, lighting, and monitoring.
Plain English
A more precise type of ILS approach that lets specially trained pilots and properly equipped aircraft land in lower clouds and reduced visibility than a normal ILS would allow.
Context Anchor
Seen on instrument approach procedures, operator authorizations, and low-visibility arrival planning for airports or heliports served by suitable instrument landing equipment.
Derivation
ILS stands for Instrument Landing System. 'Category' here is a regulatory classification — the FAA and ICAO sort ILS approaches into Categories I, II, and III based on how low the decision height and visibility minimums are allowed to go. Higher category numbers mean tighter equipment, training, and runway requirements, and lower allowed minimums.
Why Pilots Care
Allows safe landings when weather is below standard ILS minimums while adding operational flexibility at equipped airports.
Grounding Statement
Picture flying on instruments in poor visibility and not seeing the landing area until very close to the ground; CAT II rules control when that is allowed.
Intuition Check
Do not read CAT II as simply “the second type of ILS.” It means a specific low-visibility approval level with lower minimums and stricter equipment, training, and authorization requirements.
Example Sentence 1
Because the ceiling was reported at 150 feet and visibility was 1,800 RVR, the crew briefed a CAT II ILS approach to runway 27.
Example Sentence 2
Only the captain, who held CAT II ILS approaches authorization, flew the approach to the 100-foot decision height.