Yaw Maneuver Criteria Sudden Pedal Input till pedal stop(one way) must be structurally possible from VMCA to VD Sudden pedal release from fullpedal input once in steady side slip state, must be structurally possiblefrom VMCA to VD.Yaw Maneuver Criteria In case of an engine failure, the pedaldeflection required for the corrective action from the pilot after 2 secrecognition time must be possible.Loads and Rudder TravelLimitation Unit In other words, the structure and theload limits are dimensioned so as to match the yaw maneuver criteria withadequate rudder deflection limited by a judicious RTLU. However, the RTLU is not designed toprotect the Rudder Structure for any unrealistic action of the pilot on therudder pedals. Finally, the Certification Criteria donot address all possible asymmetry cases for load considerations (typically 2same side engine out configuration on a quad, sharp roll maneuvers with rudderdeflected ...)Typical Cases includinghigh loads Engine failure case:If, once the pilot has centered the target,he then commands a sharp turn unto the live engine, the side slip increasesrapidly.Thus the Yaw Damper abruptly reacts,which induces high loads.Typical Cases includinghigh loads Engine failure case Be aware that there is no restrictionto roll the aircraft with an engine failure (no additional rudder inputrequired) Furthermore with an engine failed, themaximum roll rate is limited to 7.5 o / sec (on FBW A/C at low speed, typically160 knots). At VMCA and V2 min, the certificationrequires to demonstrate adequate roll capability, with full roll input; the maximum reached is around 10 o and loads are Ok.Reason for a PTLU on A330/A340 The Yaw Damper has a great authorityin terms of rudder deflection and rudder deflection rate, on A330/A340 ascompared to A310/A320. Thus, in case of a steady state sideslip maneuver, the Yaw Damper decreases the initial rudder deflection so as tominimize the Side Slip. The PTLU is the Pedal Travel LimitUnit which limits the pedal deflection as a function of the A/C CAS.Reason for a PTLU on A330/A340When the pilot releases the rudderpedals suddenly to neutral, as requested by certification criteria, a peak of high loads can be reached (since the rudderpedal release is equivalent to a mechanical rudder movement of same amplitude)leading to a rudder deflection on opposite side.Why no PTLU on A340-500/600 The rudder channel is fully electricon the A3456 Thus the rudder pedal directly commandsthe amount of rudder as a function of the IAS and pedal deflection At a given IAS, the rudder pedals are able to command a maximum rudderdeflection, as per TLU. Any additional pedal input has no effect on the rudder(PTLU and RTLU built in the lateral law). Thrust ReversersFrom FlightSafety FundationThrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's exhaust so that the thrust produced is directed forward this acts against the forward travel of the aircraft, providing deceleration. Thrust reversers are used by many jet aircraft to help slow down just after touch-down, reducing wear on the brakes and enabling shorter landing distances. Reverse thrust is typically applied immediately after touchdown, often along with spoilers, to improve deceleration early in the landing roll when residual aerodynamic lift