An airframe includes an energy absorbing structure with a frame, a beam
mounted to the frame at a rotational joint and a collapsible member. In
response to reaching a predetermined threshold load value during a high
sink rate impact event, the collapsible member will collapse under an aft
section of the upper deck. The rotational joint operates as a virtual
hinge such that a forward section of the upper deck deforms in a
predictable manner. As the upper deck supports the high mass systems, the
high mass components are less likely to separate from their mounting and
penetrate into the crew compartment and the main rotor system will tilt
aft away from the crew compartment to minimize the likelihood that the
rotor blades may penetrate the crew compartment.