Definition
A precision instrument approach category that permits a landing with no decision height and no runway visual range minimum, meaning the approach and landing can be conducted with zero forward visibility. It represents the most demanding ILS classification, requiring fully certified airborne equipment, an autoland-capable aircraft, a qualified flight crew, and a runway and ground installation approved for Category IIIC operations.
Plain English
An ILS approach so capable that the aircraft can land even when the pilot cannot see anything outside. The aircraft's automatic systems fly the approach and landing, and no minimum visibility is required.
Context Anchor
Seen in instrument approach minimums, low-visibility landing discussions, and FAA glossary material on ILS approach categories.
Derivation
Category III is the third and most capable tier of ILS precision, with subdivisions A, B, and C in order of increasing capability. The 'C' designates the version with no decision height and no visibility minimum at all -- the most permissive of the three.
Why Pilots Care
It enables landings at equipped airports when weather would otherwise prevent any visual contact with the runway.
Grounding Statement
ILS Category IIIC describes an approved landing operation where the published minimums do not require either a runway-in-sight height or a minimum reported runway visibility.
Intuition Check
Do not assume “no minimums” means any pilot can attempt it. It means the approach category itself has no decision height or runway visual range minimum, but the operation still requires specific approval and equipment.
Example Sentence 1
Only a small number of airports and aircraft are certified for Category IIIC operations, since landing in zero visibility requires fully automated systems on both sides.
Example Sentence 2
Only aircraft certified for ILS Category IIIC can operate to zero runway visual range.