What is the floor altitude of Class A airspace?

The floor altitude of Class A airspace is 18,000 feet Mean Sea Level (MSL). This airspace commences at this altitude and extends up to and including 60,000 feet MSL. Class A airspace is designated for high-altitude operations and is primarily used by aircraft operating under Instrument Flight Rules (IFR). At this altitude, aircraft must be equipped with a transponder capable of ADS-B out, and pilots must hold an Instrument Rating to operate in this airspace. This regulation helps to ensure the safe and efficient operation of air traffic at high altitudes, which is densely populated with commercial and high-performance flights. Understanding the floor of Class A airspace is crucial for pilots in order to comply with aviation regulations and maintain safety during flight operations.