On this subject on the B737NG VNAV ....
I used to be a Captain with EZ on the -700, and rapidly developed the opinion that maybe Boeing had been a little lazy/cost saving with the -NG VNAV algorithms. Regardless of descent programming, the A/C would always go high on the energy profile .. more so than any other Boeings ... I put this down to possibly 2 things, and would be grateful for any thoughts from people with considerable experience on this aircraft ..
1. The software assumed instantaneous idle thrust at the T.O.D., and not the slow retardation of the thrust levers ...
2. They used the aerodynamic algorithms in the VNAV programming from the B737-300 Classic, which is a brick compared to the "glider" -NG. Thereby always ensuring that the new model struggles to loose energy in descent ..
Any informed comment would be appreciated ..
I.Duke