Interpretation ID: aiam1604
Chief Engineer
Eagle International Inc.
P.O. Box 4119
2045 Billy Mitchell Blvd.
Brownsville
TX 78520;
Dear Mr. Cuthbert: This responds to your July 16, 1974, request for approval of the Bendi 'dual circuit air brake system' for use on your buses in satisfaction of Standard No. 121, *Air brake systems.* In a subsequent phone call with Mr. Herlihy of this office, you stated that your only concern was whether the standard requires a parking brake system that meets the axle-by axle retardation force requirements of S5.6.1 and the grade holding requirements of S5.6.2.; The National Highway Traffic Safety Administration is unable t 'approve' plans or prototype systems for compliance with a standard in advance, because there is no way to establish that a vehicle so equipped actually meets the requirements until it has been manufactured.; With regard to your specific question, S5.6 states that each vehicl shall have a parking brake system that meets the requirements of S5.6.1 or S5.6.2 at the manufacturer's option. This means that you are free to choose a system which meets either of these requirements but does not meet both.; Yours truly, Richard B. Dyson, Acting Chief Counsel