FAR 23.2145 — Airplane Stability
FAR 23.2145 explains stability requirements for Part 23 airplanes, including static, dynamic, and control force feedback rules pilots should know.
FAR 23.2145 sets the stability standards a Part 23 airplane must meet to be certified. If the airplane is not certified for aerobatics, the design must demonstrate three things in normal operations:
- Static stability in the longitudinal, lateral, and directional axes — meaning the airplane initially tends to return toward its trimmed condition after a disturbance.
- Dynamic stability in the short period (pitch oscillation) and Dutch roll (coupled roll/yaw oscillation) modes.
- Stable control force feedback throughout the operating envelope — the controls must feel progressively heavier in a predictable way so the pilot gets honest cues from the airplane.
In addition, no airplane — aerobatic or not — may have a divergent longitudinal stability characteristic so unstable that it increases pilot workload or endangers the airplane and its occupants.
Why it matters operationally: these standards are why a certified light airplane behaves predictably in turbulence, recovers from minor upsets, and gives you usable stick-force cues during maneuvering, stalls, and trim changes.