Definition
A precision instrument approach that allows a pilot to descend lower and land in worse visibility than a standard (Category I) ILS. A CAT II ILS approach permits a decision height as low as 100 feet above the touchdown zone and a runway visual range as low as 1,200 feet. It requires specially certified ground equipment, additional aircraft equipment, and specific pilot training and authorization.
Plain English
A more capable version of the standard ILS landing system that lets qualified pilots, with the right aircraft and ground equipment, fly the approach down to a lower altitude in poorer weather before they must see the runway.
Context Anchor
Seen on instrument approach procedures and in IFR planning when a helicopter is using an ILS approach to an airport runway under lower visibility conditions.
Derivation
ILS stands for Instrument Landing System, which uses radio signals to guide the aircraft down to the runway. The categories (CAT I, II, III) were created to rank approaches by how low and how blind a pilot is allowed to fly before needing to see the runway. CAT II sits between standard CAT I and the most capable CAT III.
Why Pilots Care
Allows safe approaches in lower visibility than basic ILS procedures when the aircraft and pilot meet the required equipment and training standards.
Grounding Statement
CAT II is about permission to use lower landing minimums on an ILS, not about a different basic way of flying the approach.
Intuition Check
Do not read “CAT II” as simply “the second ILS option.” It is a specific approval level for lower-weather ILS operations with stricter requirements.
Example Sentence 1
Because the airport was reporting 1,800 feet visibility, the crew briefed and flew the CAT II ILS to Runway 24.
Example Sentence 2
CAT II ILS minimums require the pilot to have the runway in sight by the decision height.