Definition
Airspace at certain airports that changes classification depending on the time of day or whether the control tower is operating. For example, the airspace surrounding a tower-controlled airport may be Class D when the tower is open, but revert to Class E or Class G when the tower closes. The effective times and resulting classifications are published on aeronautical charts and in the Chart Supplement.
Plain English
The rules for the airspace around some airports change depending on whether the tower is open. The same piece of sky might be one type of airspace during the day and a different type at night.
Context Anchor
Seen in airport information pages, chart notes, and preflight planning when checking what airspace rules apply at the time of the flight.
Why Pilots Care
Pilots must know the published hours to apply the correct entry procedures, radio requirements, and VFR or IFR cloud-clearance rules.
Grounding Statement
Before using an airport with part-time airspace, the pilot must know which airspace class is active at that specific time.
Intuition Check
Part-time does not mean the airspace is optional or less important. It means the airspace class changes by published time or condition, and the pilot must use the rules for the class currently in effect.
Example Sentence 1
Because the destination airport had part-time airspace classifications, the pilot confirmed the tower's operating hours before departing on the night flight.
Example Sentence 2
After the tower closed, the part-time airspace classifications reverted the area to Class E, changing the required cloud clearances.