Definition
The defined airspace surrounding an instrument approach segment within which obstacles must be assessed for clearance when designing the procedure. The OEA establishes the lateral and longitudinal boundaries used by procedure designers to identify controlling obstacles, which then determine the minimum descent altitude or decision altitude for that segment.
Plain English
It is the strip of airspace around an approach path that procedure designers check for towers, terrain, and other obstacles. Anything tall inside that strip sets how low the approach is allowed to go.
Context Anchor
Seen when FAA instrument approach materials explain how LNAV, LNAV/VNAV, and circling minimums are set.
Why Pilots Care
Proper OEA evaluation ensures published altitudes provide real-world obstacle clearance during instrument flight.
Grounding Statement
Picture a designer drawing a boundary around the airport, checking the obstacles inside that boundary, and then setting an altitude that keeps aircraft safely above them.
Intuition Check
Do not think of the OEA as a painted or visible area on the ground. It is a procedure-design area used to decide which obstacles matter and what altitude gets published.
Example Sentence 1
A new tower built inside the OEA for the final approach segment forced the FAA to raise the LNAV minimums on the next chart revision.
Example Sentence 2
A tower erected near the airport prompted a full re-evaluation of the OEA before the approach could be updated.