Good to see from Double Bogey's last post some real effort to try and understand what was going on in the last moments of the flight and consider why. It is important to appreciate that this process is not about seeking to blame anyone but enable those of us that care, to focus on what could have gone wrong and where we might make even greater efforts to avoid errors - and that could refer to pilots, engineers and aircraft manufacturers. Doing so could well prevent more accidents during the time it takes for a full detailed report to be published.
I agree with Double Bogey, this does seem odd. Although not an offshore pilot, I too am baffled at just how such a big unusual attitude - especially 38 deg nose down - could occur with two experienced IR pilots.
The comment that "the crew became unhappy with the approach" etc is significant. It would be interesting to know exactly what was said on the CVR to know this. Presumably the PF Co-pilot was unhappy about something, but what exactly? How unusual is it for a missed approach and go-around to a rig to occur from a VFR approach? And when they do - let's say here because of poor visual reference in poor vis, what is the procedure? Clearly at this stage the flight is VFR, but is the policy to immediately fly by reference to instruments, or is to try and regain visual reference? If it was the former, it is harder to understand how such a big attitude change could occur - let's face it, 38 deg down looks pretty obvious and dramatic on the AI, and the starting point from a controlled approach and early go-around attitude would be a fairly normal AI picture. But if eyes were out of the cockpit believing adequate visual reference existed - maybe wrongly - I guess 38 deg down could well arise.
Whatever the level of concentration of the PNF on the approach - and clearly it should be high - one would assume it would be even higher as soon as the PF says he's unhappy and going around, with full orientation on all references - outside and instruments.
Next, after the go-around is commenced, the PF is concerned enough to ask for assistance. Is that unusual? I would have thought so, assuming he's not feeling unwell. Anyway now our hopefully orientated formerly PNF commander takes over - and within a second the aircraft is 38 deg nose down and 38 deg banked right. Another 3 seconds later it's level but still 13 deg nose down, and over the next 5 seconds presumably little more control input happens until it hits the sea. Doesn't sound like someone grappling to establish a sensible attitude on the AI.
Seems all a bit odd to me, I must say. I look forward to reading the full report especially info relating to the instruments, but there again it had a full dual panel and two pilots couldn't sort it out.