ok folks, thank you for answer
it works....
leveling was correct , gyros were reset at power up...but there were 2 other problems
1) shifting with motor off, this problem seems to be resolved with "accelerometers filter" set to 0.20
2) i don't understand why but if i connect the cc3D throttle output to the ESC, when the motor turns the ailerons shift a lot
I've tried with an external 5 Volts source to replace the ESC BEC, nothing changes
i've tried with another ESC, nothing changes
i've tried with motor not fixed on the plane to avoid vibrations, nothing changes
finally, i've connected the ESC directly on the RC receiver and nothing on the cc3D motor output....and miracle : all is perfect
flight tests of this afternoon : manual, rate and rattitude ok !
why ?.....don't know...but it flies well !..