Hello, I have a question about the 737 PMDGIn descent, after having passed below 10 000 fts, the PA disengages VNAV and set LVL CHG automatically.Why does it do it?Thanks.

Hi,If in VNAV PATH DEScent, you are probably violating the stricter speed limits applied after passing 10,000 feet.Above 10,000 feet you can overspeed up to 1 knot below the barber pole on the speed tape before VNAV disconnects. Below 10,000 feet VNAV disconnects when you're 10 knots (Correct me if I'm wrong here Randy! ;-)) above the speed restriction. Speed restriction is usually 240 KIAS if not altered.Also do a search on this topic in the forum as it has been extensively dicussed in the past.Hope it helps,