also i finally found out what the FBL problem was caused by
RTF means "rigged to Fail " ;-) the wire of esc was totally cut through by motor pinion
so someone did an awfull job on the wiring in the Kds factory.
i installed the 450m from align and esc ,and without any tampering with anything ,she flew just fine again : )
if only all crashes could be like this : )
