Learning from the past
We'll have to wait for the final accident report to be sure, but the AS30BA has done this to a few crews before in the low speed envelope. Flight test has proven that a degraded hydraulic mode when heavy with a forward CG is not controllable. One military aircraft was lost in Aus under similar circumstances and the thread concerning the Native Air AS350
[URL=http://www.pprune.com/forums/showthread.php?threadid=107709 ]
describes very similar symptoms (uncontrollable yaw and pitch oscillations). There have been others. See comments in the Native Air thread re certification.
Bottom line is that if you have to operate an AS350BA with high AUW and forward CG, try to stay in a profile that will keep you in forward flight (hard for media jocks I know). The accumulator in the TR system is supposed to stay pressurized in the case of a hyd fail and keep forces at a managable level. TR control forces in a couple of incident now would have to make one question whether in fact this has happened. The pressure appears to have been lost whether immediately (as per the HYD TEST case) or after a short time similar to the other accumulators which will only give you a minimal period in which to get some speed on and regain control. Even once in forward flight, the control forces (particularly collective) are extremely fatiguing. A run-on landing is your only controllable option (as per the manual).
There have been enough hyd system failures now that one would have to question the validity of the 10e-6 probability that justifies the simplex system. Grandfathering of certification is all well and good in theory but when practice starts to expose too many people to unacceptable risk, perhaps it is time to re-visit a failure modes and criticality effects analysis for the BA model.