Did the subject helicopter have a gyroscopic instrument of any sort, or was it completely bare bones of any instrumentation that might have helped in an inadvertent IFR situation? Most helicopters in PNG should have at least an operable attitude reference, although having said that I don't think the HL accident aircraft had one so was wondering how well equipped the aircraft might have been.

An IFR rated pilot in a VFR helicopter (but with an attitude reference) would ordinarily be able to maintain control of the helicopter in inadvertent IFR, so there might be more to this accident than that.