212man
I conducted the certification program on the AS350 BA when it first flew for the military in Aus. (BA has 355 blades on an AS350B plus some changes to the tail rotor). While control at the point of failure and recovery to landing in the degraded mode is OK throughout most of the CG/AUW envelope, there are parts of the envelope where the forces are extremely high and unpredictable (ie beyond the rated strength of control runs in the yaw axis). Despite us later instrumenting an aircraft and proving the high forces to be well above what the FARs allow, CASA and FAA took no action because they had grandfathered the certification from the DGAC (France). The FAR requires that for a failure mode "anywhere in the envelope", pilot skill and strength to control the failure and subsequently land is not be excessive. This is where interpretation is everything! According to the OEM (hence DGAC), the benign points are somewhere (=anywhere) within the envelope and therefore by testing those and ignoring the bad ones, they meet the FAR! Bottom line is, never try to hover a heavy AS350 with a forward CG. Even maintaining level flight is extremely difficult after about 25-30 minutes due to high forces in the collective.
forget to mention in my previous post. The reason we instrumented the aircraft was because we lost an AS350BA in an accident that sounds almost identical to the Native Air one. Uncontrollable yaw and pitch oscillations ending up on its side after attempting to come to a hover in a degraded hydraulic mode. Despite the lack of CASA action after the results of our testing were passed to them, the military stopped using the AS350 for loadmaster training due to the frequent exposure to high AUW hover operations. Despite OEM assurances about MTBF for the HYD system, we tracked down enough occurances world wide to deem it an uneccessary risk. Native Air just adds one more to the record. Just glad all the crew were OK.