Definition
The highest point reached during a maneuver. In a Lazy Eight, the apex is the top of each loop, where the airplane has reached its maximum pitch-up attitude and is transitioning from climbing to descending while continuing to bank and turn.
Plain English
The peak — the very top of the climb in the maneuver, just as the airplane stops going up and begins coming back down.
Context Anchor
Seen in lazy eight training when describing the shape of the maneuver and the timing of the airplane’s nose-up, turning, and nose-down changes.
Derivation
From Latin 'apex' meaning 'tip' or 'summit' — originally the pointed top of something. The aviation use keeps that exact sense: the highest point of the flight path during a maneuver.
Why Pilots Care
Recognizing the apex allows the pilot to smoothly transition control pressures and maintain the proper energy management throughout the lazy eight.
Intuition Check
Apex does not mean only the sharp point of a triangle here. In this maneuver, it means the top part of the airplane’s curved path.
Example Sentence 1
At the apex of each loop in the Lazy Eight, the airplane should be at minimum airspeed with 30 degrees of bank.
Example Sentence 2
Upon passing the apex, forward pressure is applied to lower the nose and begin the descent.