Another critical addition was the use of a power-operated stabilator, also known as the all-moving tail or flying tail, a key to supersonic flight control, which contrasted with traditional hinged tailplanes (horizontal stabilizers) connected mechanically to the pilots control column. Conventional control surfaces became ineffective at the high subsonic speeds then being achieved by fighters in dives, due to the aerodynamic forces caused by the formation of shockwaves at the hinge and the rearward movement of the centre of pressure, which together could override the control forces that could be applied mechanically by the pilot, hindering recovery from the dive. A major impediment to early transonic flight was control reversal, the phenomenon which caused flight inputs (stick, rudder) to switch direction at high speed; it was the cause of many accidents and near-accidents. An all-flying tail is considered to be a minimum condition of enabling aircraft to break the transonic barrier safely, without losing pilot control. The Miles M.52 was the first instance of this solution, which has since been universally applied.