Automatically control speed under VNAV mode of AFDS

[frank-deng]

Hi, I would like to add a feature of automatically updating the target speed under VNAV mode, which is similar to the way that Boeing 777's VNAV mode does:

• When the altitude is under 10000ft, set target speed as 250kts.
• When the altitude is above 10000ft and the aircraft is climbing/descending, set target speed as 280kts.
• When the aircraft reaches the target altitude and the altitude is above 34800ft, set target speed as mach 0.845.

PS: In my update, the vertical speed under VNAV mode is always 1000ft/min for climbing and -1000ft/min for descending.

[dogsaysmoo]

Hi Frank, The VNAV system in the 747-8 model is very rudimentary, and it isn't really set up to handle a climb or descent phase as it stands now. As such, the speed controller wouldn't be much use. Additionally, in real airlines, the switch to mach mode is made much lower and speed/thrust used to control climb/descent rates.

I'm going to leave the FLCH limits alone for now. I'm working on a new implementation for that mode right now anyway, and the limits will change.