Definition
A parameter used by the FAA's traffic management automation that establishes the airspeed at which an aircraft's estimated time of arrival at the meter fix is locked, or 'frozen,' for sequencing and metering purposes. Once an aircraft crosses the freeze horizon, its assigned arrival slot is calculated using this fixed speed value, and further speed changes do not alter the metered arrival time.
Plain English
A set speed value the traffic management computer uses to lock in an aircraft's predicted arrival time. Once that arrival time is locked, controllers work the aircraft into the landing sequence based on it.
Context Anchor
Seen in FAA glossary or ATC automation material; pilots normally do not use FSPD in cockpit procedures or radio calls.
Derivation
Freeze refers to the moment the system stops recalculating and holds the value steady. Speed parameter means a speed value used as an input to a calculation. Together: the speed value that gets locked into the arrival sequencing system.
Why Pilots Care
Correct interpretation allows timely activation of anti-ice systems, preventing performance loss or sensor failure from ice accumulation.
Intuition Check
“Freeze” here does not mean ice or cold weather. It means the ATC computer holds a speed value steady because of a preset setting.
Example Sentence 1
After the flight crossed the freeze horizon, the traffic management system used the freeze speed parameter to assign a metered arrival time at the meter fix.
Example Sentence 2
When the freeze speed parameter dropped below the current airspeed, the system automatically increased heat to the pitot tubes.