Hi, my current method for descent is using V/S while flying along VORs. I usually start to descend using V/S at about 100-130nm out. However, I do not set speed/altitude in the "Legs" page, next to each VOR. (Example: VOR 250/FL200)

 

 

How do I get what speed/altitude I should be doing for each VOR? Once I set the right Speed/Altitude, will it descend automatically and change speed automatically?

 

If it does I need VNAV enabled right?

Your STAR should have the information printed on it and the FMS should have that info stored.

 

If you're just looking for a simple mathematical equation use your ground speed in miles per minute in conjunction with a -1000 fpm descent.

 

Say you're at FL300. You're traveling 8 miles per minute (480 kts). With a -1000 fpm descent it will take 30 min to get to sea level. In that time you will travel 240 miles laterally.

 

Now 1000 fpm isn't a high rate in a turbojet so you might double that and half your numbers. Then you'll factor in airspeed as you slow and descend.

 

But 1000 fpm and speed converted to miles per minute makes mental math easier.

If you are using the PMDG 737 NGX of 747, the plane will followow the altitudes in the FMC without your intervention except that it will not go higher or lower than what is on the MCP. So for example in the 737 NGX Tutorial 1, if you set the altitude at 2000 ft as in the tutorial before hitting the TOD point, the aircraft will try to descend to the altitudes in the FMC for each waypoint without any intervention on yhour part.

 

Henri

Yes if it's the NGX you should at least do tutorial 1.

 

It explained pretty much everything I needed to know about the plane.