Empennage
The empennage is the tail section of an aircraft, consisting of the vertical stabilizer (fin), rudder, horizontal stabilizer, and elevator — and on some aircraft, trim tabs and anti-servo tabs. The empennage provides longitudinal (pitch) and directional (yaw) stability and control.
Components
- Vertical stabilizer (fin): Fixed surface providing directional stability; resists yawing motion
- Rudder: Movable surface attached to trailing edge of the fin; provides directional control (yaw)
- Horizontal stabilizer: Fixed surface providing pitch stability; counteracts the wing’s pitching moment
- Elevator: Movable surface attached to trailing edge of horizontal stabilizer; provides pitch control
- Trim tabs: Small adjustable surfaces on control surfaces that allow the pilot to relieve control forces at a given flight condition
T-Tail Aircraft
On T-tail aircraft (e.g., Fokker F28, Piper PA-28R-201T), the horizontal stabilizer and elevator are mounted at the top of the vertical fin rather than the fuselage. T-tails are susceptible to “deep stall” — a locked-in post-stall condition where the horizontal tail is blanketed by the stalled wing and pitch recovery is impossible. V-speeds for T-tail aircraft reflect this hazard.