Personal InjuryInertial Unlatching
The second problem with the RCF-65, 67/Type I is its susceptibility to become unlatched (even when previously fully latched) when a side-load is suddenly applied to the back of the belt buckle (such as during a side-impact collision or sudden rollover of the vehicle). Under these circumstances, the body of the buckle suddenly moves opposite the direction of the button, but the inertial forces acting on the button cause it to remain relatively at station and in place. This effectively causes the release button to move toward the unlatch position, thus releasing the occupant suddenly and unexpectedly. Because the release occurs as a result of the inertial forces acting on the button, this type of inadvertent unlatching is called "inertial unlatching."
Inertial unlatching can easily be demonstrated using an RCF 67 buckle, tongue and belt by fully latching, and than pulling on each end while slapping the back of the buckle firmly against a solid surface. The tongue will instantaneously separate from the buckle. Unlike false unlatching, which the buckle and automakers conceded long ago is an inherent characteristic of the RCF-67/Type I buckle, they have steadfastly declared inertial unlatching to be impossible in real world conditions.
Major attention to inertial unlatching arose in 1992 when a syndicated CBS program, "Street Stories" broadcast a segment focusing on several lawsuits which alleged that motorists and passengers (or their heirs) who had been wearing their RCF-67/Type I seat belt buckles became suddenly unlatching in accidents involving dynamic side-impact forces and were ejected from their vehicles and killer and/or serious injured. Shortly after the program aired, a petition was filed with NHTSA by a coalition of consumer groups to begin rulemaking proceedings to investigate "inertial unlatching" to enact regulations preventing buckles susceptible to false latching from being released to the public.
The reaction by the automakers and buckle vendors was vehement denial that inertial unlatching could occur and vigorous opposition to the petition. When asked to supply statistics concerning accident claims and lawsuits arising from possible inertial unlatch incidents, the auto industry reported that few if any claims or suits had been filed implicating inertial unlatching, and that the problem was essentially nonexistent.
G.M. claimed that it had commissioned independent research from an accident analysis laboratory in Arizona which proved that the inertial forces required to achieve an inertial unlatch in an accident were so severe as to be impossible in all but the most severe accidents (where the impact forces were so severe that even a properly-belted occupant could not be expected to survive).
In November, 1992, even before the industry's written responses were received and fully considered, NHTSA denied the petition on the basis that no evidence suggested inertial unlatching was actually a problem in real world conditions.
Nonetheless, since 1992, hundreds of lawsuits have been filed against the major automakers citing inertial unlatching as the cause of deaths and serious injuries to occupants of RCF-67 and Type I-equipped vehicles.
>> NEXT: The Buckle Unlatching Cover-Up and Deceit of the U.S. Government
(click on icons for more information)
SLS Consulting
