AW139 Engineer
Usually structural failure of the AW139 tail boom is contributed by landing the helicopter on its tail just prior to the main wheels. Figure it out guys
I personally saw this happen in Vergiate a 3 years ago and it also happened in the UK DEC 23 2008 on a private machine (Report not yet released) The main root cause is poor training. Don't blame the helicopter, this same scenerio has happened on many other types also.