By using Open Decent mode the FMGC would cause the FADEC "usually" to reduce the thrust to idle thrust. By turning the A/THR system off BEFORE pulling Open Descent mode, you prevent the thrust reduction and achieve a descent with a fixed speed according to strategy (standard / obstacle / fixed for ETOPS) while the FADEC commands a fixed thrust setting of MCT.
Most Obstacle strategy include escape route n addtnl oxygen,over mountainous mSA routes.^FL100.,where Ref GW before High MSA is critical. Also I think you meant set good engine to MCT, not all.?. Danke Sur,CDR
Mercy boucoup
How's the airplane keeping the speed just with autopilot without autothrust?
It's call Max Continuous thrust MCT it's a fix thrust not auto thrust involved
By using Open Decent mode the FMGC would cause the FADEC "usually" to reduce the thrust to idle thrust. By turning the A/THR system off BEFORE pulling Open Descent mode, you prevent the thrust reduction and achieve a descent with a fixed speed according to strategy (standard / obstacle / fixed for ETOPS) while the FADEC commands a fixed thrust setting of MCT.
Most Obstacle strategy include escape route n addtnl oxygen,over mountainous mSA routes.^FL100.,where Ref GW before High MSA is critical.
Also I think you meant set good engine to MCT, not all.?.
Danke Sur,CDR