FAR 25.301(a) says, "Strength requirements are specified in terms of limit loads (the maximum loads to be expected in service) and ultimate loads (limit loads multiplied by prescribed factors of safety). Unless otherwise provided, prescribed loads are limit loads."(adsbygoogle = window.adsbygoogle || []).push({});

FAR 25.303 says, "Unless otherwise specified, a factor of safety of 1.5 must be applied to the prescribed limit load which are considered external loads on the structure."

FAR 25.305(e) says, "The airplane must be designed to withstand any vibration and buffeting that might occur in any likely operating condition up to VD/MD, including stall and probable inadvertent excursions beyond the boundaries of the buffet onset envelope."

Question: Does that mean that Vd is the limit case, i.e. structural loads at Vd are multiplied by a factor of safety to provide a "realized margin of safety" beyond Vd?

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# Question about limit and ultimate loads

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