Tried the other day to get to flight level 370 with a fully loaded A/C, just a bit below the MTOW. Just could not get there. Airspeed dropped to about 0.55 mach and speed could not recover to the 0.78m . I had to loose altitude and get back speed while decending to FL 330. Is this the way the real thing behaves? Should we step climb to burn fuel (which is not indicated on the FMC)? Will appreciate any response on that one.ThanksBK

It is not efficient to go so high with such a high GW.BTW, how were you climbing? Please don't say V/S. If so, you just learned why it has dangers (i.e., no speed protection).I'm pretty sure the 800/900 will have max/opt altitudes for a given weight in the FMC.Lee Hetherington, PP-ASEL (KBED)