You're right about Nigeria BB. Here it's not just that there's no quality media to get involved, but the AIB is completely hopeless and inefficient. It's to the advantage of the operating companies also as they hope these things will just go away and be forgotten.
Bristow also have another AIB investigation pending into the Citation XLS which they wrote off with a heap of Total management on board at DNPO.
In addition to the Bristow accidents you mentioned, nothing more seems to have been heard about the 2 OAS AS350 fatal accidents or the one with a privately registered Bell 407 which killed a child at Aba.
As for some of the near misses ..... the ACN S76C+ which was so over-torqued that the blades nearly came off (and the pilot reported no defects in the technical log
) and the Caverton SA365N which came back with part of the tail pylon missing and a length of power cable embedded in the leading edge of a main rotor blade - and the pilot reported that he felt no unusual vibrations. Believe me, there are a whole heap more out there that the operators don't want anyone to hear about
