It's a measure of how the aircraft responds to your inputs in a manoeuvre — Page 235, Lesson 293

I want to walk you through the structure of this part of the course, because it lays out the whole roadmap for what we're about to study. This is the table of contents for the stability and control section, and every heading here is a distinct topic we'll cover in order. We start with Stick Force Per 'g' — that's the force you feel in the control column when you pull to create one 'g' of load factor. It's a measure of how the aircraft responds to your inputs in a manoeuvre. Then we have Tailoring Control Forces — that's about how designers adjust the feel of the controls, so the forces are neither too heavy nor too light for the pilot. Next comes Longitudinal Control — that's control about the lateral axis, the pitch axis, the up-and-down rotation of the nose. Under that we have three specific requirements: the Manoeuvring Control Requirement, the Take-off Control Requirement, and the Landing Control Requirement. Each one is a different phase of flight where the elevator must be able to do its job. After that we move into Dynamic Stability — that's how the aircraft behaves over time after a disturbance, whether the oscillations die out or grow. Under that we have Longitudinal Dynamic Stability, which splits into two specific modes: the Long Period Oscillation, which is also called the Phugoid, and the Short Period Oscillation. The phugoid is the slow, gentle pitch-and-speed oscillation; the short period is the fast, heavily damped one. Finally, we have Directional Stability and Control — that's stability about the normal axis, the yaw axis, the side-to-side rotation of the nose. So the whole flow is: control forces first, then longitudinal control requirements, then dynamic stability in pitch, then directional stability. That's the complete map of what we're about to study.