FabrizioI just set everything up the same and tried the flight.Worked a treat. Screenshots of the FMC and also of the cockpit on climbout are attached.You didn't have a 100kt tailwind at 500ft agl did you?There has to be something simple happening here. What are your PMDG options set to for overriding the autopilot (AFDS settings I think)?Email me off forum and lets try and work through this from the beginning up.Peter Lloyd

In pic 4, you didn't let the airplane accelerate to the scheduled "flaps up" retract speed brfore you selected "Flaps Up." Here the deal, I think: Notice the FMC set a clean airspeed of 275 knots. The FMC thinks You are real heavy . . . and you are! Your notes show a GTOW of 957,478 lbs. "747400F LoadManager.exe52052 Fuel634976 ZFWPax 2160Cargo 268290"That's a tad overweight. If you want to try this, that's OK. But there's no telling where the CG is gonna be. If you want to continue these "test flights," try letting the airplane acellerate all the way to the scheduled flap retract speed before you "pull the rug" out from under poor ol' Captain AFS. Even overweight, it appears you were OK just prior to this flap retract event. The deceleration that is occurring here means the nose was lower just a second ago. Something happened to rock the nose up. Look at the FD bar. This means the Autopilot has the stab trimmin' nose down and the elevator pushing hard to get the nose down ImmdeIaTEly. Something upset the airplane, just moments before. It might have been that early flap retraction. Try it again and retract the flaps right on schedule . . . not early . . . then try it at 1 million lbs! You're our new test pilot. How heavy can you go???Pics 1 through 3 look OK . . . except, make sure the To page flap selection (LSK 1L) and the actual flap setting match before TO.

Just a quick comment... and not totally relevant to your problem.. but why don't you have LNAV and VNAV armed before the take off roll?CheersCraig

>The FMC thinks You are real heavy . . . and you>are! Your notes show a GTOW of 957,478 lbs. >>>"747400F LoadManager.exe>52052 Fuel>634976 ZFW>Pax 2160>Cargo 268290">I think you may be confusing ZFW with OEW :)GW = ZFW + Fuel = 687,028Kevin