Definition
The phase of flight covering ground movement from the parking area to the runway and the subsequent acceleration and lift-off into the initial climb. In the context of instrument system inspection, it is the period during which the pilot verifies that flight instruments, navigation equipment, and engine indications respond correctly as the aircraft moves and accelerates, confirming systems are functioning before committing to flight.
Plain English
The part of the trip where the airplane drives along the ground to the runway, then speeds up and lifts off. During this time the pilot watches the instruments to make sure everything is working properly before climbing away.
Context Anchor
Seen in departure procedures and instrument-system checks, especially when confirming that required instruments and navigation equipment are working before and during the start of flight.
Derivation
Taxi comes from the early-1900s use of taxicab, because aircraft on the ground were said to move like a cab through traffic. Takeoff is literally the moment the aircraft takes itself off the ground.
Why Pilots Care
Verifies that navigation instruments provide accurate information from the moment the airplane leaves the ground, preventing loss of situational awareness in low-visibility conditions.
Intuition Check
Do not treat “taxiing and takeoff” as only the moment the airplane leaves the runway. In this context, it covers the connected ground-to-air phase: moving to the runway, lining up, accelerating, lifting off, and beginning the climb.
Example Sentence 1
During taxiing and takeoff, the pilot confirmed the heading indicator turned in the correct direction and the airspeed indicator came alive as the aircraft accelerated.
Example Sentence 2
Any discrepancy noted while taxiing and takeoff requires returning to the ramp rather than continuing into instrument conditions.