Definition
An air traffic management technique that uses calculated times of arrival, rather than distance-based spacing, to sequence aircraft to a runway, fix, or arrival point. Controllers and automation tools assign each aircraft a target time to cross a meter fix or threshold, and adjustments in speed, route, or altitude are made en route so the aircraft arrives at that point at the assigned time, smoothing traffic flow into busy airports.
Plain English
Instead of telling planes to stay a set number of miles apart, the system gives each plane a specific time to arrive at a certain point in the sky or at the runway. Pilots and controllers then adjust speed and routing so each aircraft hits its assigned time, which spreads traffic out evenly.
Context Anchor
Seen in NextGen discussions about managing arrival traffic into busy airports.
Derivation
Metering comes from the idea of a meter — something that measures and regulates flow. Just as a water meter controls the rate water enters a system, time based metering controls the rate aircraft enter a runway or arrival fix, using time as the measuring unit instead of distance.
Why Pilots Care
Reduces holding patterns, fuel burn, and arrival delays while increasing runway throughput.
Grounding Statement
Picture several aircraft headed to the same airport, each with a planned time to arrive at a key point so they do not all reach it at once.
Intuition Check
Do not read metering as simply measuring time. Here it means regulating aircraft flow by using planned times.
Example Sentence 1
Because time based metering was in effect, ATC asked us to slow to 280 knots about 200 miles out to meet our assigned arrival time at the meter fix.
Example Sentence 2
During peak traffic, time based metering helped sequence arrivals without extended holding.