Originally Posted by
eckhard
For example, if your lower target altitude is at a waypoint that is still in the cruise portion of the FMC flight-plan, you may not be able to enter it on the legs page without an “S” after the numbers. For example 310S which means a step-change in the cruise....
I fear I did not get this point
My understanding of climb, cruise and descent phase with active VNAV was this.....
Climb phase is the phase from takeoff to the set cruise level.
As soon as I have reached the T/C (cruise level) the plane automatically switches to cruise phase and stays in this phase until it reaches the T/D where it automatically descends when a lower altitude is set on the MCP. If Des Now is pushed the plane starts the descent earlier with a moderate vertical speed until it reaches the planned descent path of the FMC. As soon as the plane has started to descend from cruise level to any lower altitude the plane is automatically in descent phase. How can the plane still stay in cruise phase when going down from cruise level to any lower altitude?? I understand the procedure of step climb to higher altitudes but not to lower ones? Would be great if someone can explain this to me. Thank you!