blowdown limit

English

Noun

blowdown limit (plural blowdown limits)

1. (aviation) The maximum deflection that a control surface is capable of reaching under given flight conditions, past which the aerodynamic forces acting on the control surface exceed the maximum opposing force available from the control surface's actuators.
   • 2001 March 27, National Transportation Safety Board, “3.2 Probable Cause”, in Aircraft Accident Report: Uncontrolled Descent and Collision With Terrain, United Airlines Flight 585, Boeing 737-200, N999UA, 4 Miles South of Colorado Springs Municipal Airport, Colorado Springs, Colorado, March 3, 1991‎^[1], archived from the original on 8 May 2022, page 139:

     The National Transportation Safety Board determines that the probable cause of the United Airlines flight 585 accident was a loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide.