Originally Posted by
LOWI
Surely after KRISE, where the a/c had reached it's altitude restriction, and with 190 in the MCP ALT, the a/c ahould have continued it's descent?
Prior to the approach environment (where the behavior changes*) VNAV will always fly level until it reaches an idle path to the next relevant restriction. With multiple restrictions, it will stair-step down this way, between level and idle. The MCP altitude is irrelevant to all this, except that if it happens to be reached at any point in the process, it will level there (annunciating VNAV ALT instead of ALT HOLD)
So after KRISE at 240, it is normal for it to level until the next top of descent (even if there is nothing prior to the discontinuity, and this next top of descent doesn't exist). If you want to proceed down early, you have to specifically tell it somehow.
The "somehow" is where you start getting differences between software revisions, customer options, etc. V/S is always one way, of course, which completely disregards your positioning in relation to any future fixes. On ours, there is the ability to stay in VNAV, push the ALT INTV button on the MCP (or select DESCENT NOW from the descent page in the FMS, which does the same thing except in one somewhat convoluted edge case) and it would take the 190 from the MCP, set that as the new VNAV level altitude, and begin a 1000 fpm descent (annunciating VNAV PTH) to get there.
* on an approach, instead of stair-stepping down at idle, it draws a slope between the altitudes at each fix.