Interpretation ID: aiam2842
United States Senate
Washington
DC 20510;
Dear Senator Glenn: This is in response to your letter of June 7, 1978, pertaining to you constituent's, Mrs. Carl A. Koch, concerns regarding motor vehicle seat backs that do not permanently lock.; Federal Motor Vehicle Safety Standard No. 207, Seating Systems, cop enclosed, requires that a hinged or folding occupant seat or occupant seat back shall be equipped with a self-locking device for restraining the hinged or folding seat or seat back and a control for releasing that restraining device. The industry is currently installing two types of seat back latches, a manual conventional type of latch and a new inertial locking device. The standard requires that the locks withstand a load 20 times the weight of the hinged portion of the seat and is not required to withstand the load of an occupant striking the seat back. Rear occupants are expected to be restrained by the rear seat belts, however, seat backs in locked position, because of some padding, do provide some protection for unrestrained occupants.; The seat back latch referred to by your constituent is an inertial sea back latch which is neither required nor prohibited by the standard. The industry, in an effort to facilitate rapid egress from a motor vehicle in emergency situations, such as a fuel fire, have introduced inertial seat back latches. The seat back latch will lock when the low forces of a panic breaking situation occurs or a high impact force occurs, releasing itself automatically when the inertial forces drop to a predetermined force, normally approximately .5g, allowing rapid occupant egress.; We believe there can be positive post-crash escape advantages for th inertial type seat back latches, however, it would appear from Mrs. Koch's experience that it may be warranted to initiate an investigation of the type of inertial latches installed in the 1978 Ford Granada. Accordingly, I am forwarding a copy of your letter to our Office of Defects Investigation for their action to determine if and what corrective action may be warranted.; I hope this information is helpful to you in responding to Mrs. Koch' inquiry. If I can be of further assistance, please let me know.; Sincerely, Michael M. Finkelstein, Acting Associate Administrator fo Rulemaking;