There have been no additional checks instigated as a result from this accident.
I have read all the speculation on here and here I my thoughts on some of the 'ideas'
1. Both engines flaming out- very unlikely. However if I'm led to believe the sortie times are correct they would have been extremely close to running out of fuel
2. MGB failure- very unlikely. If the MGB had had a failure or seized it would be in the bottom of the Clyde and the aircraft spread across a big area
3. TR drive failure- possibly. If the TRDS had failed the drive shaft cowling would be completely trashed. Looking at the pics this seems fully intact. Trust me I've seen the results of driveshafts letting go. It's messy. If it had failed further up the drivetrain then this would be harder to see from the pics. So a maybe.
4. Fin cracking -Very unlikely. The new ASB was instigated after one modified ring frame was found to have a small crack. This would take ages to propagate. Anyway this aircraft I would think by its age would have the big carbon fibre patch modification and not be subject to the ASB.
5. Tail rotor hub failure- very unlikely. Looking at the pics although the hub and stators are detached this is a result of the fin striking the roof on landing. If you look at the blades six are still attached. The four missing would be again as a result of the impact on the roof.
6. Reports of he blades not turning. My experience of night time ops is that blades are extremely hard to see at night and if his side strobes were on this has the effect of 'stopping the blades'
7. Engines popping.- could be engine surge. Again my experience of surge is of a popping/banging sound. What could cause this is the engines shutting down with power still being pulled in.
8. Lack of damage to blades- hard one to quantify. All I can bring to this is that they made a landing on the roof and managed to shut the rotors quickly with the brake. The aircraft then fell through the roof under its weight. They only thing that I can't get my head round is how they died. All I can suggest it the roof timbers etc came through into the cabin and killed them??
So in conclusion. We don't know. What we do know is that this is one of the safest aircraft out there and none have crashed due to a catastrophic mechanical failure. And before you say...the Japanese one was due to somebody mistakenly thinking the thread was left hand and not right hand and weakening the rod.
I would and have flown on testing recently with no worries at all.