Plain English Meaning

A detailed look at everything tall around an airport — hills, towers, buildings, trees — used to build a custom escape plan in case an engine fails on takeoff. It tells the crew exactly where to fly and how steeply to climb to stay clear of those obstacles.

Full Definition

A specialized study of the terrain, structures, and other obstructions surrounding a specific airport that determines the procedures, climb gradients, and routing a turbine-powered aircraft must use to safely depart with one engine inoperative. It supplements the standard FAA departure procedures by accounting for obstacles that lie beyond the normally evaluated for two-engine .