Definition
The angle of attack at which the wing produces the most lift for the least drag, giving the aircraft its best overall aerodynamic efficiency. On an angle of attack indicator, OAA is the reference point used for best-performance maneuvering, including best glide and maximum endurance.
Plain English
The wing angle that gives the airplane the best balance of lift and drag. Flying at this angle gets the most performance out of the wing.
Context Anchor
Seen in discussions of angle of attack indicators, especially indicators that show a target approach condition instead of only warning that the wing is near a stall.
Derivation
‘Alpha’ is the Greek letter used by engineers as the symbol for angle of attack — the angle between the wing and the oncoming air. ‘Optimum’ comes from Latin meaning ‘best.’ So Optimum Alpha Angle literally means ‘the best angle of attack.’
Why Pilots Care
Flying at this angle maximizes fuel efficiency, climb performance, or range while maintaining safe margins from the stall.
Intuition Check
Optimum does not mean the airplane is at its best for every possible purpose. Here it means the chosen target angle for the current flight condition, such as approach, and it is still below the stall angle.
Example Sentence 1
After the engine quit, she pitched for the OAA mark on the AOA indicator to stretch the glide as far as possible.
Example Sentence 2
On final approach the OAA bug helped maintain the most efficient descent angle without risking a stall.