A320 procedures for one thrust reverser inoperative; why is the old procedure more efficient? I recently watched the Mayday series about TAM Airline Flight 3054. Landing on a short runway with only one thrust reverser in use, and the documentary explained something like:


  The old Airbus procedure was to put both engines' controls on IDLE and then put only one of them on REVERSE. The new procedure says that you put both of them on REVERSE, regardless of if one of them doesn't work. The captain seemed to aim at the old procedure, because it is known to be more efficient.


I wonder how it is more efficient? Does the position of the controls for the second motor really influence the behaviour of the first one?
Does the position of the controls for the second motor really influence the behaviour of the first one?


No, it influences the activation of various other systems like the autothrust, the airbrakes, as well as the thrust reversers.


  how it is more efficient?


Because in the new procedure the engine with non-functioning reverser starts to spool up before the system realizes the reverser did not deploy and cuts it again, so for a moment it produces forward thrust. The old procedure avoids this.