Sudden roll over ended terribly wrong

What happens in this video ?

This Hughes 500 helicopter was about to land when it suddenly rolls over with catastrophic results.

Comments

Will
Port Dover

(Canada)
This is the old Magnum P I helicopter, however it was not involved in filming here it was doing long line work for the power company. The pilot had an electrical problem ( runaway cyclic trim ) and the helicopter got away from him
2nd January, 2011
John Youngs
Tacoma, Wa

(Usa)
This is the old "Magnum P.I." television show (with Tom Selleck) Hughes 500D helo that crashed during filming.
16th June, 2008