This helicopter is a SA 330BA from the french ALAT, Army aviation.
ALAT operates with a crew of 3, 2 pilot and 1 flight engineer in the middle jump seat. This configuration could seem strange, but think that army helicopters are to be operated on the field, far from their home base. For the light maintenance and deep preflight, it's the way better to have somebody really competent in that matter.
This accident occured around 5 years ago during a training with police special forces. The landing was quit hard and what you can see on the video is the result.
Cheers