Definition
An air traffic management technique used by ATC to sequence and space arriving aircraft well before they reach the terminal area. Coupled Scheduling (CS) links together the schedules of multiple traffic flows so that aircraft from different routes merge smoothly into a single arrival stream. Extended Metering (XM) extends that scheduling outward — sometimes hundreds of miles from the destination airport — so that small speed adjustments made early in the flight remove the need for larger delays, holding, or vectoring later.
Plain English
It is ATC's way of organising arriving traffic far in advance. Instead of waiting until aircraft are near the airport and then issuing big delays, controllers nudge each aircraft's speed early on so they all arrive at the right spacing without holding patterns or sharp turns near the destination.
Context Anchor
Seen in traffic management, arrival-delay, and metering discussions. A pilot may experience XM as an early speed assignment, route adjustment, or delay before reaching the busy arrival area.
Derivation
‘Couple’ comes from the Latin copula, meaning ‘a link or bond’ — here it means linking separate traffic flows into one coordinated schedule. ‘Metering’ comes from the Greek metron, ‘a measure’ — controlling the rate at which aircraft arrive, like metering water through a tap. ‘Extended’ simply means the metering reaches further out from the airport than traditional methods.
Why Pilots Care
Pilots may receive speed, routing, or time assignments tied to XM to meet scheduled arrival slots.
Analogy
It is like coordinating traffic lights along several roads before cars reach a crowded downtown area, instead of trying to sort all the cars out at the final intersection.
Intuition Check
Do not read “metering” as measuring something like fuel or electricity. In this context, metering means controlling the timing and spacing of aircraft. Do not read “coupled” as physically connected. Here it means the scheduling information between ATC facilities is linked.
Example Sentence 1
Center issued a speed reduction to 280 knots two hundred miles from the destination as part of Extended Metering into the arrival.
Example Sentence 2
XM couples scheduling between two busy airports so their arrival flows stay coordinated.