I heard three different versions, all supposedly the real inside information about what was going on in the aftermath of this accident, so that there is some confusion.
Usually it seems that a report does get completed on each accident in Nigeria but trying to find it, ah! So, nothing unusual so far in this.
From what I have been told, the patient's corpse was recovered, along with one of the rear doors bearing witness marks from the tail rotor.
The other victims and the wreckage are in deep water, reportedly around 4-5 thousand feet. Supposedly an unsuccessful side-scan sonar search was attempted and then abandoned so that the present location of the wreckage is unknown. On the other hand, one fellow told me that the wreckage had been located and viewed by some sort of remotely controlled mini-submersible; this doesn't seem to be the case.
I was told that the a/c was not fittted with an autopilot, so that one accident scenario was that something may have distracted the crew's attention, when they hit the surface, detaching the door which then hit the tail rotor. The patient, who had a hand injury, was accompanied by another oil worker; there was no flight nurse or third crewmember so that the flight crew may have been required to do something for the patient and his companion.
Another scenario is that the door was mis-rigged and came off in flight, taking out the tail rotor.
A third scenario is that the door was opened or came open after being struck by some unsecured object in the cabin so that it then came off and took out the tail rotor.
The a/c had, reportedly, not been fully fuelled and the rig's fuel stopped pumping for some reason so that they were on their way to another rig to take fuel for the trip to Port Harcourt when the accident occurred.
This is about all that I have heard about this accident. Given that one is often told, by some supposed insider, exactly what is going on, only later to be told by the same insider something completely different, who can really say what went on. The people who know something are either dead or not talking.
I think we can assume that steps will be taken to prevent a similar accident in future without necessarily satisfying the curiousity aroused or, more importantly, letting people in the aviation community learn what went on for their edification.
Nigeria has an unfortunate history of keeping secrets about accidents. That may be one reason for its high accident record. I think you could put that down to a non-safety culture, one that is changing only slowly.