Definition
Any portion of flight involving taxi, takeoff, landing, and all other flight operations conducted below 10,000 feet, except cruise flight, during which the flight crew must remain focused on operating the aircraft and avoid non-essential activities or conversation.
Plain English
The parts of a flight where the workload is high and a mistake can quickly become serious — basically taxi, takeoff, landing, and any flying below 10,000 feet that isn't steady cruise. During these times, pilots stay focused only on flying.
Context Anchor
Seen in safety discussions, CFIT prevention, crew briefings, sterile cockpit procedures, instrument approaches, departures, and landing operations.
Derivation
‘Critical’ comes from the Greek kritikos, meaning ‘able to judge or decide.’ A critical phase of flight is one where good judgment and full attention matter most — small errors here have the biggest consequences.
Why Pilots Care
The majority of CFIT accidents occur during these phases, requiring heightened focus and sterile cockpit discipline.
Analogy
It is like driving through a busy intersection. Nothing may be wrong, but it is not the time to look away or start an unrelated task.
Intuition Check
Do not read “critical” as meaning an emergency is already happening. Here it means the flight segment has higher risk and demands focused attention.
Example Sentence 1
Once the aircraft descended through 10,000 feet, the crew stopped non-essential conversation because they had entered a critical phase of flight.
Example Sentence 2
The approach is treated as a critical phase of flight because the aircraft is descending toward potentially obscured terrain.