framer, no worries.
According to what I understand, VNAV will revert to LVL CHG to prevent overspeed. As you state, there are many possible combinations and options to consider. That is why I enjoy these conversations, and there are many combinations that are difficult to consider. Field operations, has exposed many, many issues.
As you stated VNAV will disco to LVL CHG if the ac goes below min speed, but my understanding is that VNAV will disco if you go overspeed with gusts (hence the 240) It also may disco to VNAV SPD on overspeed. In reality, I am unclear as to gust overspeed vs overspeed, based on what I have experienced.
Perhaps this is where the confusion comes in, at least on my part, but, what I do know is that it is a problem (or at least was) when you code a waypoint at 10K with a speed restriction of 250kts on the B models. Airports and the advance of procedure design,...the coding itself has introduced anomalies that had never occurred before, such as a RWY point over 10K, the box just could not do it. (the damn 10K is hard coded and buried in the code of so many areas...)
Regards
Last edited by underfire; 5th Jul 2016 at 09:59.