After I programmed a flight in the FMC and, as far as I know, did,nt forget anything, the aircraft stalls when reaching FL310 or more. The FMC gives the altitude predictions but while climbing, speed falls to stallspeed. What am I forgetting, can someone give me some ideas?Thanks.

How heavy are you?Aircraft fly higher as they burn off fuel, they don't just fly straight up to the higher Flight Levels after takeoff.Thats what step climbs are for, one steps upwards as weight (fuel) burns off.Ray

I think I constantly forget to use the load manager. Would this be the cause????

Yes and no.The load manager will let you adjust weights of the cargo/pax on board. You can use the standard fuel/payload section within FS to adjust fuel and stuff.Right out of the box so to speak, the aircraft is beyond maximum weights in FS9.A maximum weight aircraft is going to fly around in the FL270-FL290 range until if burns off some of that fuel weight. The engines while being powerful, do have their limits. Zooming straight up to FL410 is not going to happen, just watch your angle of attack as you climb up there, as the plane starts to labour, the AoA will start getting higher and higher until you finally stall. This is going to vary depending on temperature and pressure, but all planes have a flight envelope that once exceeded results in a high speed stall or low speed stall.Ray

I was thinking that all this was done by the FMC. Am I right that in the FMC of the PIC767, this did'nt happen? As far as I know the aircraft would climb to the requested level without pilots intervention.By the way, I have another strange problem when using a SID from EHAM. When reaching a new waypoint with an altitude constraint, the FMC says "unable next altitude" and the aircraft goes in a steep dive. Flying is not as easy as everybody says..........Thanks for your response, looking forward to a FMC guide of this aircraft.