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Aircraft Structure: Empennage

In this lesson, we will discuss the definition, parts, and types of the empennage of an aircraft.

Basically, the tail unit is just like a smaller version of the wings. They have the same parts namely: stringers, skin, and spars.


The structure or parts of an aircraft’s empennage is similar to the structure of wings.


  • Main load bearing member of the wing
  • Absorbs stresses (bending and twisting)
  • Aircraft can be single, twin, or multi-spar construction
  • Part of the torsion box 


  • The external part of the wing that is connected to the fuselage
  • Where the maximum bending moment occurs


  • Absorbs the load and distribute it to other structures
  • Outer cover of the wing


  • Longitudinal structural members that assist the longerons
  • Also known as stiffeners – stiffens the skin
  • More numerous and lighter in weight than longerons


  • Support the structural members such as the spar, stringers, and longerons
  • Maintains the shape of the wing
  • Makes up the framework of the wing
  • Useful to distribute the loads being experienced by the aircraft


  • Reinforces the skin to maintain the aircraft’s circumferential shape.

Note that the torsion box consists of stringers, ribs, skin and spars. 

Empennage/Tail Unit/Stabilizers

aircraft tail empennage stabilizer rudder elevator

Empennage is used to move the airplane’s nose left/right or up/ down. It also reduces the control pressures.

The aircraft’s tail or empennage includes the vertical and horizontal stabilizers where the rudders, elevators, trim tabs and other secondary control surfaces are placed. Empennage provides the aircraft’s longitudinal and directional stability and control.

Types of Empennage

  • Conventional Tail
    •  Advantage: Adequate stability and control
    • Disadvantage: Heavy vertical stabilizer
  • Cruciform Tail
    • Advantage: Weigh less than T-tail and allows the engines to be placed at the rear.
    • Disadvantage: Does not have a surface area advantage due to the endplate effect.
  • T-Tail
    • Advantage: Lighter tail design than the conventional tail
    • Disadvantage: Prone to twisting and bending loads
  • V-Tail
    • Also referred to as “butterfly” tail
    • Advantage: Lightweight and contains lesser components
    • Disadvantage: Complicated control system and it is hard to construct because of its complex design
  • Twin Tail
    • Advantage: Enables higher angle of attack range, increasing low-speed controllability, and control in the event of an engine failure
    • Disadvantage: Tends to weigh more
  • Dual Tail
    • Advantage: Provides smoother flow
    • Disadvantage: Heavyweight
  • Triple Tail
    • Advantage: Provides smoother flow
    • Disadvantage: Greater weight
  • Inverted Tail
    • Advantage: Adds clearance at take-off and landing time, and stability in crosswind situations
    • Disadvantage: Hard to construct
  • Inverted Y-Tail
    • Advantage: Can yaw without aileron
    • Disadvantage: Inefficient tail configuration

Vertical Stabilizers or Fin

  • This is where the rudder is located.
  • Rudder – It allows the pilot to move the aircraft sideways.

Horizontal Stabilizers