Accident to the helicopter AS350 registered N790AM on 06/12/2017 on Davis-Monthan AFB, Arizona [Investigation led by NTSB / United States]

Preliminary data based on the notification from the United States authorities:

N790AM, an AS350B3, was patrolling southern AZ looking for scouts and dropping agents off. The pilot made a landing that he thought was firm but not hard. They refueled, conducted a walk around, and returned to Tucson AB. Maintenance subsequently found the tailboom to be wrinkled and the K flex on the short shaft delaminated.