VNAV at Takeoff

[maussuam]

Hey Jean-Philippe,

I checked the 747-400 AOM from an european airline, they usually take off with LNAV and VNAV armed, so there must me a solution your problem.
I found a very good manual of the PDMG 747-400 FMS here: click me
According to that (Page 40), you can set Thrust Reduction Height and Acceleration Height independent from each other in the Takeoff Ref page (which in reallity is also made for some Noise Abatement Procedures).
You set the ACC height together with flap setting in the flaps field (LS1L). If it is set to 1500, the commanded speed should remain at V2+10 until reaching the height. I hope this is working.

Regards
Bastian

[Sean Nixon]

Try page 2 of the TAKE OFF page.

[Jean-philippe]

The PM CDU has these features displayed in the THRUST and TAKEOFF pages but they are not functional. I tried to set 10/1500 in the LSK 1L of the TAKEOFF REF page to set acceleration haight at 1500' but the VNAV continues to set his own speed targets below 1500'. About the thrust reduction altitude there is also an field in the LSK 3L of the TAKEOFF REF page but it is not functional at all and the setting remains to FLAPS 5 CLB (witch is not followed by the autothrottle).

Again PM software limitations ?

[Jean-philippe]

Try page 2 of the TAKE OFF page.

I don't have any page 2 on the TAKEOFF REF page. I use 747-400 CDU build 492.