A study of many crash deceleration records suggested a simplified model of a crash deceleration pulse, which incorporates the essential properties of the pulse. The model pulse
is considered to be composed of a base pulse on which are superimposed one or more
secondary pulses of shorter duration. The results of a mathematical analysis of the
seat-passenger deceleration in response to the airplane deceleration pulse are provided. On
the basis of this information, presented as working charts, the maximum deceleration loads
experienced by the seat and passenger in response to the airplane deceleration pulse can be
computed. This maximum seat-passenger deceleration is found to depend on the natural
frequency of the seat containing the passenger, considered as a mass-spring system. A
method is presented that shows how to arrive at a combination of seat strength, natural
frequency, and ability to absorb energy in deformation beyond the elastic limit that will
allow the seat to serve without failure during an airplane deceleration pulse taken as the
design requirement.
![[Logo Image]](/images/airscrew_trans_2in.gif)