High Level Airspace is defined as what altitude?

High Level Airspace is defined as what altitude?

• A. ≥ 18,000 feet ASL
• B. < 18,000 feet ASL
• C. 30,000 feet
• D. 12,000 feet

Answer: (A)

High Level Airspace begins at 18,000 feet above mean sea level and extends upward to the upper limits (in the U.S. this is Class A airspace up to FL600). This is the portion of airspace where ATC clearance and IFR operation are required. So the defining boundary is the start at 18,000 feet ASL—anything at or above that is high level airspace. The other options place you below that boundary (12,000 or 18,000 as the ceiling, or 30,000 without indicating the starting point) and don’t identify the correct threshold.

High Level Airspace begins at 18,000 feet above mean sea level and extends upward to the upper limits (in the U.S. this is Class A airspace up to FL600). This is the portion of airspace where ATC clearance and IFR operation are required. So the defining boundary is the start at 18,000 feet ASL—anything at or above that is high level airspace. The other options place you below that boundary (12,000 or 18,000 as the ceiling, or 30,000 without indicating the starting point) and don’t identify the correct threshold.