An aircraft seat assembly configured in accordance with an example embodiment of the invention offers a light weight and comfortable seat cushioning system that also provides energy-absorption and enhanced passenger maneuverability in extreme conditions such as may be experienced in a hard landing situation. The cushioning system includes a crushable, energy-absorbing layer, a main cushioning layer, a smaller ishial insert layer which may be the same as the main cushioning material and a semi-dynamic pneumatic cell which uses a dual action breather valve to vary its inflation with changes in cabin pressure. The seat cushion may be finished with a covering of cloth or upholstery.