Interpretation ID: aiam2155
Senior Vice President
Administration
Transcon Lines
P.O. Box 92220
Los Angeles
CA 90009;
Dear Mr. Throop: Thank you for your December 6, 1976, letter in which you detail th difficulties experienced by Transcon Lines with certain antilock devices installed in satisfaction of Standard No. 121, *Air Brake Systems*. You explain that Transcon disconnected both defective and potentially defective antilock devices, and you ask for an explanation of your legal responsibilities for the disconnections under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S 1391, *et seq*.).; After the first purchase of the vehicles for purposes other tha resale, the only statutory prohibition against disconnection of safety equipment such as the antilock system is found in S 108(a)(2)(A) which provides:; >>>S108(a)(2) (2)(A) No manufacturer, distributor, dealer, or motor vehicle repai business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard [except for repair]. . . .<<<; A person that does not fall within the enumerated categories is no prohibited from disconnection of the antilock system after purchase. Also, I have spoken to Federal Highway Administration officials who assure me that, because a defective system is involved, the Bureau of Motor Carrier Safety would not require that the system be connected.; Two National Highway Traffic Safety Administration (NHTSA) staf engineers visited the manufacturer of the antilock systems installed on the tractors and trailers in question to investigate the problems you describe. In replacing the sensors on the trailers, it was discovered that improperly manufactured exciter rings (all produced on August 9, 1976) appear to be the source of the problem. In addition to agreeing to replace all the sensors on the trailers in question, the antilock manufacturer has identified all of the sensors manufactured on the day in question and has initiated a defect recall campaign with the NHTSA. In the case of tractor malfunction, a shuttle valve that has been used for years on trailers appears to be sticking because of excessive corrosion on the particular vehicles in question. It is our understanding that the rate of air loss caused by the sticking can be compensated for by the air compressor and does not pose a safety hazard.; With regard to your concern that the systems 'fail safe,' Standard No 121 specifies that 'electrical failure of any part of the antilock system shall not increase the actuation and release times of the service brakes' (S5.5.1). This provision does not require that the system be completely incapable of malfunction, but the manufacturers have made concerted efforts to make the systems 'fail safe.' Quite apart from the requirements of the standard, each of the antilock manufacturers faces the same prospects for product liability suits on its antilock products as in the case of any other of its products.; We will continue to monitor the defect campaign efforts of the antiloc manufacturer to ensure that an unsafe condition does not arise.; Sincerely, John W. Snow, Administrator