ILS Category IIIA: Provides for approach without a decision height minimum and with runway visual range of not less than 700 feet.

ILS Category IIIA: Provides for an approach with no minimum decision height and a minimum runway visual range of 700 feet or more. This category is utilized for landing approaches in low visibility conditions, typically in fog or heavy rain. The aircraft can be guided to the runway with precision using instrument guidance. The approach can be made up to 50 feet above the runway, allowing for a smooth landing even in adverse weather conditions. This is one of the most advanced categories of ILS and requires specialized training for pilots to operate safely and efficiently.