Plain English Meaning

The parts of a flight where the most can go wrong and the crew needs to focus completely on flying. This covers ground movement, takeoff, landing, and any flying below 10,000 feet other than steady cruise.

Full Definition

The segments of a flight during which the workload is highest and the margin for error is lowest, specifically taxi, takeoff, landing, and all flight operations conducted below 10,000 feet (except cruise flight). During these segments, flight crews are required by the Sterile Flight Deck Rule to limit their activity to duties essential to the safe operation of the aircraft.

Context Anchor

Seen in sterile flight deck or sterile cockpit discussions, especially when deciding what conversation or activity is allowed during taxi, takeoff, landing, and low- flight.