Federal Motor Vehicle Safety Standards; Occupant Crash Protection

This document amends a final rule that was published in March 1997 that expedites the depowering of air bags. This correcting amendment clarifies that: The ``corridor'' defining the bounds of permissible sled acceleration will be shifted to contain the time at which the sled acceleration first reaches 0.5 g, to account for ``lag'' in the components of the sled system. This will make the sled test easier to conduct because early variations in sled acceleration lag will not in themselves cause the sled pulse to be outside the required acceleration corridor. While the neck injury criteria for flexion bending moment and extension bending moment are intended to be measured by the six-axis load cell, located in the dummy head, the values measured at that point will be mathematically corrected to reflect the corresponding values at the occipital condyle, a lower point near the base of the dummy's skull. Prior to testing, the engine, transmissions, axles, exhaust, vehicle frame, and vehicle body must be rigidly secured to the vehicle and/or the sled. Fluids, batteries and unsecured components will be removed. These steps will prevent spikes in the acceleration curve during the test that would result from these components moving.