Original Message

Agree with the tailboom failure theory but a simpler cause could be loose rivets initiating a crack, which would be hard to detect on a black tailboom. Bell PSE has been drawing attention for years, during maintenance conferences, to these types of cracks, sometimes starting at the driveshaft cover clips. They show pictures of cracks almost 6" long before being detected. When you look at the NTSB photo of the fracture on the remaining tailboom section, you see how it jumped from rivet to rivet at the bulkhead location. Could this be related to the observed tail wag?