Originally Posted by
TheBusFlyer
To make it simple, would the system react in the following way:
- If the target can be reached in less than 2min, AT will compute a given amount of thrust. This will definitely lead to an output VS.
- Once the thrust is set, it won’t keep changing. In a perfect world, no elevator input would be required for a perfectly trimmed aircraft. The aircraft would climb at the MCP window speed at the target ROC set by thrust. But as we are not in a perfect world, elevator does pitch for speed once the thrust is set…as FLCH gives priority to speed. Our target VS (ROC/ROD) set by THR will change but the system disregards these changes…it’s just some initial math done to compute a given amount of thrust set for the climb.
Any thoughts?
Yes, it is just that simple. When you press FLCH, the ATS helpfully makes a guess at how much thrust you will need to get there in about two minutes, sets that, then drops to HOLD and leaves you to it. Speed is always controlled by the elevator.