HORK Enterprises
3221 Quick Road
Holly, MI 48442, USA
 +1 (248) 328-0231
 consult@hork.com

Crashworthiness for Commercial Aircraft

Under Brite/Euram sponsorship a three year European research program commenced in 1993 aimed at providing guidelines for the improvement of aircraft crashworthiness design techniques. This was to be achieved by the use of extensive analytical studies supported by experimental work on materials, components and full scale aircraft structures. The program initiative was inspired by the 1989 Kegworth air disaster that seemed it should have been more survivable. Part of this work was the application of multi-body and finite element analysis techniques to study the immediate environment of the occupant and the reaction of the occupant to the crash impulse and interaction with the surrounding structure. In Cooperation with Aircraft manufacturers such as British Aerospace Airbus and MBB, and seat manufacturers such as Keiper-Recaro, an analysis project comprising occupant simulations and sled testing was conducted for this programme. An elaborate model consisting of two seat rows, populated with a total of five dummies was developed and validated against sled tests. In a survivable airplane crash, an injury such as a broken leg or ankle, can become deadly if it prevents the passenger from escaping a post-crash fire or flooding. Injury criteria for such injuries have been established from automotive research and have been incorporated in the crash dummy models. Computer simulations models were used to analyze the forces on occupants, seat frame and floor structure during a crash landing. The crash accelerations were represented by horizontal and vertical triangular pulses of 16G and 14G magnitude respectively per AS 8049. These are not easily simulated on a Hyge sled, because of the long displacement, but pose no problem for simulation models. The analysis assessed the dynamic forces on the seat structure and clearly showed the benefits of assuming a brace position in case of an emergency landing. The work has contributed to make near survivable aircraft accidents, more survivable, by establishing analysis methods and tools to assess crash events.