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my_controls · June 30th, 2007, 16:34

Let's say you're at FL300 cruising. You're cleared to FL200, so you dial it up and start the descent in VNAV. 200 appears in the scratchpad now and if you enter it on the cruise page I've noticed that the FMC commands a slower speed all of a sudden.

I was told that the new speed is the cruise speed you would have at the target altitude, in this case FL200. Is this correct and if so, why is this feature there? I would have expected it to maintain the path (I'm assuming it's a VNAV PTH descent) and leave the speed setting be.

June 30th, 2007, 16:34	#1
my_controls Newbie Join Date: Aug 2005 Posts: 20	B738 FMC vnav descent speed? Let's say you're at FL300 cruising. You're cleared to FL200, so you dial it up and start the descent in VNAV. 200 appears in the scratchpad now and if you enter it on the cruise page I've noticed that the FMC commands a slower speed all of a sudden. I was told that the new speed is the cruise speed you would have at the target altitude, in this case FL200. Is this correct and if so, why is this feature there? I would have expected it to maintain the path (I'm assuming it's a VNAV PTH descent) and leave the speed setting be. __________________ "Now take out some power.... slowly... centerline... keep the nose up, centerline, nose up, watch out, add power! My controls" Repeat 20 times daily. Just another day at the office.