Use of Tethered Small Unmanned Aerial System at Berkman Plaza II Collapse

A tethered Small Unmanned Aerial System (sUAS) provided structural forensic inspection of the collapsed Berkman Plaza II six-story parking garage. The sUAS, an iSENSYS IP3 miniature helicopter, was tethered to meet US Federal Aviation Administration (FAA) requirements for unregulated flight below 45 m (150 ft). This created new platform control, human-robot interaction, and safety issues in addition to the challenges posed by the active, city environment. A new technique, viewpoint-oriented Cognitive Work Analysis (CWA), was used to generate the 4:1 human-robot crew organization and operational protocol. The sUAS over three flights was able to provide useful imagery to structural engineers that had been difficult to obtain from manned helicopters due to dust obscurants. Based on these flights this work shows that tethered operations decreases team effectiveness, increases overall safety liability, and in general is not a recommended solution for sUAS flight.