S-76
SAS, RVDT and lynnx,
This is conjecture based on the quite limited information in the posted accident report, and assuming that the input rod linkage to the forward main servo has become disconnected.
If there was no pilot or AFCS input to the controls at the moment of separation, the servo would stay in place and from that point that attachment point on the swashplate becomes a fixed point, a fulcrum if you will. Some of the comments referred to the servo fully extending. That might be possible if there was an input at the moment of separation. However, if the forward servo had gone hardover ( remember, a disconnected control input means that the follow-up link would not stop the servo from moving at an intermediate point ), then the initial described aircraft reaction would have been much more violent than has been posted.
Back to the fulcrum point. With the attachment from the forward servo to the swashplate fixed in space, , then other control inputs would be affected. A collective input would then tilt the swashplate, instead of moving it up or down at whatever tilt it had. The head moment that is the moment placed on the vehicle thru tilting the control axis, is quite strong on the 76 ( some have seen the videos of the armed 76 doing rolls etc ), so the resultant unexpected cross coupling would certainly baffle the crew.
At this point, it is hard to say much more, except that the FDR analysis ought to shed more light on this aspect of the crash, and translate pure conjecture into fact. Focus has to be on the disconnect, maintenance history etc.
John