View Full Version : Airbus and Boeing thrust questions.

4th Oct 2004, 22:49

A couple of questions from an interested amateur...

1. Airbus auto-thrust. If I understand correctly, with the thrust levers set in the CLIMB gate, the range of thrust that can be delivered is from idle to maximum climb thrust. What thrust do you get if you disconnect the auto-thrust with the levers in CLIMB? Given that CLIMB can provide a wide range of thrust settings, what happens in this case?

2. Boeings don't have TOGA, FLEX/MCT or CLIMB gates. I know there is usually a button to provide TOGA settings, but how are the other settings actually selected (short of manually moving the throttles)? Can the throttles be advanced to the equivalent of FLEX/MCT or CLIMB settings by any means other than pushing them forward?

Thanks in anticipation.

4th Oct 2004, 23:11
Depends on if AutoThrust is disconnected by the instinctive disconnet buttons on the thrust levers whereby they thrust will match Thrust lever position (TLA). If disconnected by pressing the Autothrust Pb then depending on what mod state will get "Thrust Lock" or matching TLA

Max thrust for each phase of flight computed (either manually or by FMS) and displayed. Autothrust will maintain melected speed by using upto the max for that mode.

Simplistic (like me) but hope it helps

6th Oct 2004, 23:24
In other words (saying thesame as BusBoy):

With the thrust levers in the CLB detent:
If you press the red buttons on the thrust levers you get climb thrust, as this is where the thrust levers are.
If the autothrust fails or you push the autothrust button on the MCP (which is a non-normal way of disconnecting it and is seen as failure by the system logic), you get thrust lock. This means that the current thrust is held, until you move the thrust levers. As soon as you do (even only a little bit) you get thrust commanded by the thrust lever position you set.

On the 737, if I remember correctly, one can set the N1 limit in the FMS, and then select N1 mode. The autothrottle then sets this N1. I may be wrong though, it's been awhile.