Definition
The specific path through the air that the pilot has chosen or been assigned to fly, defined by a target altitude, heading, airspeed, and attitude. In instrument flying, it is the reference path against which deviations are measured and corrected.
Plain English
The exact path you intend the airplane to follow — the altitude you want to hold, the direction you want to point, and the speed you want to maintain. Anything different from that is a deviation you need to correct.
Context Anchor
Seen in instrument flying when the pilot compares the airplane’s actual movement with the path required by a published procedure, an air traffic control instruction, or a training maneuver.
Derivation
‘Prescribed’ comes from Latin praescribere, meaning ‘to write before’ or ‘to lay down as a rule.’ A prescribed flightpath is one that has been set down in advance — by the pilot’s plan, the clearance, or the procedure — rather than improvised in the moment.
Why Pilots Care
Following the prescribed flightpath ensures terrain clearance, traffic separation, and regulatory compliance in instrument conditions.
Grounding Statement
Picture the aircraft trying to stay on an invisible path through the sky that has already been laid out for that part of the flight.
Intuition Check
Do not read prescribed as medical or optional advice. In this context, it means specified in advance and expected to be followed.
Example Sentence 1
The student noticed a 100-foot drop below the prescribed flightpath and added a touch of back pressure to climb back to altitude.
Example Sentence 2
ATC cleared the aircraft direct to the fix to rejoin the prescribed flightpath after a vector.