Definition
In ATC usage, to lock a planned arrival or departure sequence so that the order and assigned times for the affected aircraft no longer change. Once a sequence is frozen, controllers commit to that order and the computed times become the working plan for spacing and metering.
Plain English
When ATC freezes a sequence, they have decided the order aircraft will arrive or depart, and that order is no longer being shuffled. The plan is locked in.
Context Anchor
Seen in air traffic control, traffic flow, and computer-based planning discussions, especially when flights are being sequenced or delayed.
Derivation
From the everyday sense of 'freeze' meaning to hold something still. ATC borrowed the word to describe the moment a flexible plan becomes a fixed one.
Why Pilots Care
Accumulation of ice on wings, propellers, or sensors reduces lift, increases drag, and can cause loss of control or inaccurate instrument readings.
Intuition Check
Do not read freeze or frozen here as an icing term. In this FAA glossary context, it means locked or held unchanged in a planning or control system.
Example Sentence 1
Once the arrival sequence was frozen, the controller began issuing speed assignments to maintain the spacing.
Example Sentence 2
After landing in sleet, the crew inspected the wings to confirm no frozen accumulations remained on the leading edges.