Definition
A computed landing time for an arriving aircraft that, once the aircraft reaches a defined point in its arrival, is locked in by the air traffic control system and no longer recalculated. The frozen time is then used as the reference for sequencing and metering the aircraft into the arrival flow.
Plain English
It is the planned landing time the system works out for your aircraft and then stops adjusting. Once it is frozen, controllers use that fixed time to slot you into the arrival lineup at the airport.
Context Anchor
Seen in NOTAM contractions and air traffic delay or flow-control information involving expected landing times at busy airports.
Derivation
Freeze' is used here in the computing sense — to stop a value from changing. The system keeps recalculating the predicted landing time as the flight progresses, and at a chosen moment that number is 'frozen' so controllers and pilots can plan against a stable target.
Why Pilots Care
Once the FCLT passes, controllers and dispatchers can no longer shift the aircraft's landing slot without manual intervention, directly affecting arrival planning and potential holding.
Intuition Check
“Freeze” does not mean ice or cold weather here. It means the calculated landing time is locked in place for planning.
Example Sentence 1
After we crossed the metering fix, our FCLT was set, and the controller gave us a small speed reduction to meet it.
Example Sentence 2
The system issued an FCLT of 1430Z, fixing the aircraft's place in the arrival sequence.