Crashworthiness analysis of commuter aircraft seats and restraint systems

Abstract

Abstract During the past five years, the U.S. Federal Aviation Regulations (FARs) have been significantly modified with respect to strength of seats and restraint systems, their attachments to the aircraft structure, and the means for their evaluation. Aircraft accident data, human tolerance levels, and aircraft structural characteristics have been considered in developing the new standards, which require dynamic testing of seats and restraint systems. FAR Part 23, which deals with small airplanes, was first amended to require dynamic testing of seats and restraint systems for normal and utility (general aviation) aircraft with capacity for fewer than 10 passengers. Performance criteria are similar to those specified by the U.S. Federal Motor Vehicle Safety Standards for automobiles, but also include a limit on pelvic force in order to prevent spinal injuries that may be caused by the vertical component of impact force. Similar regulatory actions, although requiring somewhat different dynamic test conditions, have also been implemented for transport aircraft, which are covered by FAR Part 25, and for helicopters, under FAR Parts 27 and 29. Commuter-type aircraft have not been affected by the FAR modifications. Commuter types seat 10 to 19 passengers, are closer in size to general aviation aircraft than to large transports, and are also covered by FAR Part 23. The Federal Aviation Administration (FAA) is currently involved in a research program that includes full-scale aircraft drop tests, sled tests of seats, and computer simulations that should lead to a proposal for amendment of the regulations for commuter-type aircraft. The objectives of this paper are to describe the research program and to document some conclusions that may be drawn from its results concerning seat and restraint system design, dynamic testing, and acceptance criteria.