A variable-position horizontal stabilizer changes the pitch simultaneously with the

flaperon A flaperon (a portmanteau of flap and aileron) on an aircraft's wing is a type of control surface that combines the functions of both flaps and ailerons. Some smaller kitplanes have flaperons for reasons of simplicity of manufacture, while s ...

setting.
Normally the

horizontal stabilizer A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplan ...

also known as

tailplane A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplane ...

is fixed and has a hinged

elevator An elevator or lift is a wire rope, cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or deck (building), decks of a building, watercraft, ...

, a

stabilator A stabilator is a fully movable aircraft horizontal stabilizer. It serves the usual functions of longitudinal stability, control and stick force requirements otherwise performed by the separate parts of a conventional horizontal stabilizer and el ...

is another method that combines the functions of an elevator and a horizontal stabilizer.
The variable-position horizontal stabilizer is governed by the flaperon setting: the settings of the flaperon control produce corresponding changes to the stabilizer angle of incidence, thus defining the trim airspeed in relation to the flaperon requirements. The conventional elevator remains in trail, minimizing trim drag. Flaperon settings are used to optimize the

lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobile ...

and drag of a wing. When the flight requires low speed the flaperons are in a positive position and when the flight requires high speed flaperons are in a negative position.

Sources

*https://web.archive.org/web/20070418051732/http://www.glidingmagazine.com/FeatureArticle.asp?id=368 *https://web.archive.org/web/20070202111444/http://www.alisport.com/eu/images/img_news/Volaresett04/VOLARE_SETT04.htm Aircraft controls