INVESTIGATION OF SEAT BELT WEBBING SERVICE LIFE

Various models of belts of different ages were collected in two climatic zones in the United States and subjected to a uniform testing procedure. The outstanding features resulting from the field work included the revelation that the sample pattern as originally planned could not be fulfilled, and the confirmation of a marked lack of interest in seat belts by plane owners and servicing people at airports. A large quantity of belts over ten years old (pre TSO) were found still in use. The laboratory tests showed that of 399 seat belt samples tested, 42 percent failed to meet the minimum strength requirements of Technical Standard TSO c22. Cotton webbing belts showed a higher incidence of failure than belts made with synthetic fiber webbing. Laboratory tests showed more assembly failures than webbing failures. The performance of all cotton belts tested leads to the conclusion that cotton webbing should not be used in aircraft safety belts. It is recommended that the minimum strength requirements for both webbing and assemblie be raised. Improved administrative procedures for the enforcement of minimum aircraft safety belt standards are also recommended.