Interpretation ID: aiam2554
AM General Corporation
32500 Van Born Road
Wayne
MI 48148;
Dear Mr. Shillinger: This responds to your oral request of March 28, 1977, for clarificatio of the language of S5.4.1 of Standard No. 217, *Bus Window Retention and Release*. In particular, you ask whether the long side of a rectangular roof exit is required to be parallel to the center line of a bus.; S5.4.1 requires that an exit provide an opening large enough to admi unobstructed passage, keeping a major axis horizontal at all times, of an ellipsoid generated by rotating about its minor axis an ellipse having a major axis of 20 inches and a minor axis of 13 inches.' Further, S5.2.1 of the standard states that a roof exit shall meet these requirements when the bus is overturned on either side. The requirement that the major axis be kept horizontal while the bus is on its side means that the major axis, and therefore the long side of the rectangular roof exit, would be parallel to the center line or the side wall of a bus.; Sincerely, Frank A. Berndt, Acting Chief Counsel