September 9, 200322 yr Fellow Captains,While SU1.1 fixed the most obnoxious problems with VNAV, there have still been some complaints, and I've noticed the issue below.If you adjust your MCP altitude when VNAV is engaged, particularly in a climb or descent mode, the aircraft seems to ignore any constraints entered in your route, and you'll often get a VNAV disconnect with an "unable next alt" message.The way to avoid this is to get in the habit of disengaging and re-engaging VNAV if you make any changes to the MCP altitude. This "resets" the next altitude constraint on your PFD and VNAV seems to function normally.Anthony, I don't know if you've already addressed this issue in SU2, but if not - I hope the info proves helpful. Perhaps looking for a change in the MCP altitude could prompt an automatic restart of the routines that calculate and set the next level-off altitude when VNAV's engaged.Clear skies!
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