Sometimes when I am landing the 747-400,I got a violent pith up after spoiler deployment,but this is something that happens from time to time,not always but often in windy condition.One time it was actually balloning a few seconds after mainwheels contact.I then decided to go around.Then the trim was jammed in the full up position,and I was so near stalling.Is this a software problem,bad piloting or a very unforgiving aircraft?

what's your ref speed and your mass when that happens? Sounds like you might be too fast and light.Cheers- Balt

I had the vref according to the weight,but I added half of the headwind component to the vref

Not sure if I understand you correctly but - spoilers should not be engaged while LANDING. They are of course deployed after touchdown. Performing a go-around with them deployed could be very very bad. I've never seen it do that after landing but the rule is to get the nose down fast in this situation. You should be committed to land after your mains are in contact. Best,Randy J. Smith<<>>

No,I armed them on approach,They deployed normally on touchdown,but the nose suddenly rise to the air after a few second.It happens some time,And I don,t know what am doing wrong.In these situations, I never had any trim problems during approach.

Seems to me that you are coming in too fast. This happened to me once when i first purchased and flew the Queen. I came in a shade too fast and did not flare appropriately. Even though i felt my touchdown was ok, the aircraft nosed up after touchdown and i had to go around. Check your landing speed and flare altitude.Anthony