Aircraft control surface system

A pop-up finger spoiler for an aircraft wing, the spoiler having a length, a width and a thickness, and being moveable between a deployed configuration and a stowed configuration wherein:

• the spoiler when deployed in a direction along its length has a cross-section, transverse to its length, with a concave surface having a curvature which gives the spoiler rigidity to resist bending about an axis across its width;
• and
• the spoiler when stowed has at least a portion having a cross-section, transverse to its width, with a convex profile having a curvature which allows the spoiler to be compactly stowed in the wing.

A method of moving a deployable control surface member between a retracted position and a deployed position via an opening in an aircraft structure, such that:

• the deployable control surface member, when in its deployed position, extends from the opening such that a distal end of the deployable control surface member is presented to airflow local to the aircraft structure, there being a first distance measured along a straight portion of the deployable control surface member from the distal end, along a length of the deployable control surface member, to an opposite end of the straight portion;
• the deployable control surface member, when in its retracted position, is contained within an internal volume of the aircraft structure;
• the internal volume having a maximum depth dimension that is less than the first distance.