Report:
https://www.cpf.navy.mil/Portals/52/...5ijQ384A%3d%3d
From the report:
The mishap was caused by the failure of the yellow damper hose on LT 616 in-flight, resulting in total loss of main rotor system damping and the immediate onset of severe vibrations upon touchdown.
So the accident was caused by ground resonance resulting from rotor head line failure. If the report is taken literally a single fluid hose to a single damper failed resulting in the loss of damping in all four blade dampers!! How can this be true? Can someone familiar with the design verify that this is not the case? If true how could such a design be approved?
Assuming that the report’s wording was poorly chosen and should have been “loss of damping to the single blade”, this raises the further question on why loosing a single blade’s damper would be catastrophic? Note: Commercial certification requires demonstrating safe operation with a single damper failed.