pss 777 climb rate and step climb

[Guest ishfaq]

my ususal flights in the 777 are about 8 hours long. At touchdown, I usually have 30-50 000 lbs of fuel. I normally climb using VNAV. The plane climbs at a steady rate to FL200. Above this altitude, it climb rate falls. The climb speed given by the fmc is normally 315/.839. Above FL300 it climbs very very slowly. I use VNAV for changing altitiude during a step climb and the climb rate is also very slow. Is the rate of climb supposed to slow down so much???Am I doing the step climb correctly??? Would it be better to type in a lower speed and manually select a cimb rate of 500fpm???Thanks for your help,Ishfaq Fazal

[B777ER 2,475]

Many factors can influence climb behavior. Did you have a strong tailwind when climbing? What was the recommended altitude per the FMC VNAV page? What CLB thrust setting were you using? For a flight of 8 hours, I would use a CLB thrust setting of CLB and managing my lower altitude climb via the V/S (not going over 3000 fpm) and when getting up around, FL200, letting VNAV take over. The T7 has very powerful engines and on take off will climb very rapidly even heavily loaded. Many here in the forum thought that PSS had messed up when in fact they did not. The T7 needs such power when up at higher altitudes to achieve their cruise altitude. The trade off is that lower altitude climb rates must be closely managed.