CONVERTIBLE AERONAUTICAL SOFA WITH INSERTABLE BACK AT GIVEN HEIGHT

Sofa (10) for a passenger transport vehicle such as an airplane, comprising a seat (11), a backrest (12) and a structure (13) supporting them, said sofa being convertible into at least two positions each presenting a total usable surface for the passenger: a sitting position in which the backrest is upright relative to the seat and a lying position in which the backrest is folded into the same plane relative to the seat; said seat presenting a length (L11) sufficient to allow a passenger in the sitting position to completely extend his legs; in the sitting position, the backrest (12) is partially stored below the seat (11) in a space (131) of the structure (13), so that the total usable surface in the sitting position is less than the total usable surface in the lying position.