US Patent 10040552 Alert system for an unmanned aerial vehicle

An unmanned aerial vehicle for aerial transportation of delivery items. The unmanned aerial vehicle includes an attachment device to fasten and unfasten one or more delivery items to the unmanned aerial vehicle, a motor to aerially transport the one or more delivery items along a delivery route, a sensor mounted on the unmanned aerial vehicle to detect at least one environmental variable during the delivery route, and an alert system to generate a status associated with the unmanned aerial vehicle along the delivery route to an observer when the environmental variable exceeds a predetermined threshold.