Definition
Expanded obstacle clearance areas applied at fixes, navaids, or waypoints where an aircraft is expected to change course. Because an aircraft cannot turn instantly and may overshoot the new course, the protected airspace is widened on the outside of the turn to account for turn radius, wind drift, and bank angle. Within turning areas, the same minimum obstacle clearance applied to the en route segment must still be provided.
Plain English
When you turn at a fix, you don't pivot on a dime — you swing wide. Turning areas are extra blocks of protected airspace built around the turn so terrain and obstacles are still cleared even though you've drifted off the centerline while turning.
Context Anchor
Seen in IFR en route obstacle-clearance discussions when a published route bends or changes direction at a named navigation point.
Why Pilots Care
These areas guarantee that a turn can be made at the planned altitude without striking terrain or obstacles, directly supporting safe IFR navigation.
Grounding Statement
Picture the airplane rounding a corner in the sky; the turning area covers that rounded path instead of only the straight route lines.
Intuition Check
Do not read “turning areas” as any place where a pilot feels there is room to turn. In this context, it means specific protected airspace used for IFR obstacle clearance during a planned route turn.
Example Sentence 1
The procedure designer expanded the turning areas at the fix to account for the higher true airspeed and wider turn radius at altitude.
Example Sentence 2
Obstacle clearance calculations for the turning area used a standard 25-degree bank to define the protected airspace width.