Definition
An air traffic control tool that calculates and assigns precise speed adjustments to arriving aircraft so they cross specified points along an arrival route at the correct time intervals behind preceding traffic. Controllers issue these speeds to maintain consistent spacing between aircraft on the same arrival, reducing the need for vectoring, holding, or last-minute speed changes near the airport.
Plain English
A ground-based system that tells controllers what speeds to assign each arriving aircraft so planes land in a smooth, evenly-spaced stream instead of bunching up or needing to be sent on detours.
Context Anchor
Seen in air traffic control, arrival management, and traffic-flow discussions, especially when multiple aircraft must be spaced smoothly toward the same airport or route point.
Derivation
"Interval" comes from Latin intervallum, meaning the space between two walls or points — here, the time gap between arriving aircraft. "Ground-based" signals that the calculations are done by ATC computers on the ground, not by equipment in the cockpit.
Why Pilots Care
Reduces holding, fuel burn, and controller workload while increasing arrival capacity at busy airports.
Grounding Statement
Picture several aircraft inbound to the same airport: the ground system helps the controller keep each one arriving with enough room behind the one ahead.
Intuition Check
Do not read “ground-based” as meaning the aircraft are on the ground. Here it means the spacing calculations and controller tools are located with air traffic control, not carried out mainly by onboard aircraft equipment.
Example Sentence 1
ATC issued a GIM-S speed of 280 knots to maintain proper spacing behind the company flight ahead.
Example Sentence 2
Pilots received speed adjustments via data link under ground-based interval management-spacing to maintain the required spacing on final approach.