Hello - before I report let commend you on a job well done with this project. Now, my issues is when I am at the top of the decent and set up my vnav speed to 280 on the decent. The aircraft does not keep the 280 speed during the decent. Not sure if this is only isolated to me but 737-900u does not behave on that manner, nor the 737-800 zibo. A little bit more info Route KFLL THNDR4 THNDR LBV DEAKK5 KTPA on the arrival DEAKK 250/11000 decending from 22000 at the top of decent the plane catches the vnav glide path but the initial speed as set in the FMC DES profile overspeeds. To prevent the airplane to overspeed further I have to use the speed break all of way down to the decent. Is there something that I am doing wrong or this is a bug. Again as I mentioned it the other mods do not behave this way. I really love this plane and feedback is greatly appreciated.