Definition
A defined airspace surrounding a fix or navigation aid in which a holding pattern entry or course reversal turn is begun, used by procedure designers to ensure the aircraft remains within protected airspace throughout the maneuver.
Plain English
The zone of airspace around a fix where a pilot is expected to start a turn during a holding entry or procedure turn, so the aircraft stays inside the safe, obstacle-cleared area.
Context Anchor
Seen in instrument procedure design and in discussions of how charted turns are protected for obstacle clearance.
Why Pilots Care
Keeps the aircraft inside protected airspace and prevents overshooting the desired course during instrument flight.
Intuition Check
Do not read this as just any place where a pilot chooses to start turning. In this context, it means a specifically protected area built into the procedure design.
Example Sentence 1
The procedure designer sized the turn initiation area to account for the aircraft's speed and bank angle during the holding entry.
Example Sentence 2
Identify the turn initiation area on the approach plate before beginning the procedure turn.