An aircraft empennage comprising a torsion box having a front spar and rear spar, a first control surface comprising a front spar and a trailing edge and a second control surface comprising a front spar, a trailing edge, and means (5, 6, 7, 8) for pivotally attaching the first control surface and the second control surface to the rear spar of the torsion box, characterized in that the first control surface is an inboard control surface which comprises: - two lateral ribs (9, 9'), first lateral rib and second lateral rib attached each one either to the trailing edge and to the front spar arranged, - six inner ribs (11, 12, 13, 14, 15, 10) located between the two lateral ribs (9, 9') wherein one inner rib is a central rib extended from the trailing edge to the front spar arranged so as to define an angle α4 with the spar in the range between 75o-95o, two inner ribs, first and second inner ribs, are located between the first lateral rib and the central rib and inclined an angle α2, α3 towards the first lateral rib and three inner ribs, third, fourth and fifth inner ribs, are located between the second lateral rib and the central rib and inclined an angle α5, α6, α7 towards the second lateral rib, and - an inner spar parallel to the front spar and to the trailing edge, attached to the central rib and extended from the second inner rib inclined towards the first lateral rib to the third inner rib inclined towards the second lateral rib, and characterized in that the second control surface is an outboard control surface which comprises: - two lateral ribs (20, 20'), first outboard lateral rib and second outboard lateral rib, attached each one either to the trailing edge and to the front spar of the outboard control surface and arranged so as to define each lateral rib an angle, β1, β5, - three internal ribs (17, 18, 19) located between the two lateral ribs (20,20') wherein - a first rib is a central rib extended from the trailing edge to the front spar arranged so as to define an angle β3 with the spar in the range between 80o-100o - a second rib is located between the first lateral rib and the central rib and inclined towards the first lateral rib, - a third rib is located between the second lateral rib and the central rib, inclined towards the second lateral rib, - Two internal spars (24, 24') parallel to the front spar and the trailing edge extended from the first lateral rib to the second lateral rib, and - One internal spar parallel to the front spar and the trailing edge extended from the second rib to the third rib. - two lateral ribs (9, 9'), first lateral rib and second lateral rib attached each one either to the trailing edge and to the front spar arranged, - six inner ribs (11, 12, 13, 14, 15, 10) located between the two lateral ribs (9, 9') wherein one inner rib is a central rib extended from the trailing edge to the front spar arranged so as to define an angle α4 with the spar in the range between 75o-95o, two inner ribs, first and second inner ribs, are located between the first lateral rib and the central rib and inclined an angle α2, α3 towards the first lateral rib and three inner ribs, third, fourth and fifth inner ribs, are located between the second lateral rib and the central rib and inclined an angle α5, α6, α7 towards the second lateral rib, and - an inner spar parallel to the front spar and to the trailing edge, attached to the central rib and extended from the second inner rib inclined towards the first lateral rib to the third inner rib inclined towards the second lateral rib, - two lateral ribs (20, 20'), first outboard lateral rib and second outboard lateral rib, attached each one either to the trailing edge and to the front spar of the outboard control surface and arranged so as to define each lateral rib an angle, β1, β5, - three internal ribs (17, 18, 19) located between the two lateral ribs (20,20') wherein - a first rib is a central rib extended from the trailing edge to the front spar arranged so as to define an angle β3 with the spar in the range between 80o-100o - a second rib is located between the first lateral rib and the central rib and inclined towards the first lateral rib, - a third rib is located between the second lateral rib and the central rib, inclined towards the second lateral rib, - a first rib is a central rib extended from the trailing edge to the front spar arranged so as to define an angle β3 with the spar in the range between 80o-100o - a second rib is located between the first lateral rib and the central rib and inclined towards the first lateral rib, - a third rib is located between the second lateral rib and the central rib, inclined towards the second lateral rib, - Two internal spars (24, 24') parallel to the front spar and the trailing edge extended from the first lateral rib to the second lateral rib, and - One internal spar parallel to the front spar and the trailing edge extended from the second rib to the third rib.