In Every hover chart in FMS 28 the Gross Weight line will turn left at around 5300` DA.What happens is when you get higher in weight and higher in altitude,you can`t stay out of the H/V diagram.It`s not that the 407 isn`t capable of carrying 5250 lbs at 11000`Da,you just can`t land,takeoff or do in ground effect maneuvers above 11000`DA.As a matter of fact the chart only allows you to takeoff below 4400lbs at 11,000`DA.So if you takeoff at sea level using FMS 28 at 5250 GW and plan on landing at a location that`s over 5300`DA you need to put the FMS 28 away and go with the regular chart AND make sure you have burnt enough fuel that your weight satisfies regular chart limits.