UAV requirements documents should c

UAV requirements documents should contain reliability and maintainabilitythresholds that, when combined with the desired distance and airspeed characteristics,support the desired ETOS. A difficulty arises when the presupposed values used to estimate the ETOS for the system are not demonstrated during OT. A determinationmust then be made as to whether or not the required ETOS can be met when some of the required parameters have not been. As an example, the demonstrated values for TUAV reliability metrics during IOT were below those required in the ORD. It was determinedthat the ETOS requirements could be met given the inherent reliability of the system provided by multiple air vehicles.