The National Transportation Safety Board (NTSB) is issuing a final rule, amending the definition of “Unmanned aircraft accident” by removing the weight-based requirement and replacing it with an airworthiness certificate requirement.
The weight threshold is no longer an appropriate criterion insomuch as unmanned aircraft systems (UAS) under three-hundred-pounds frequently operate in high-risk environments—such as beyond line-of-sight and over populated areas. The amended definition will allow the NTSB to be notified of and quickly respond to UAS events germane to the board’s mission of enhancing transportation safety
Formerly, the NTSB defined an unmanned aircraft accident as: An occurrence associated with the operation of an unmanned aircraft that takes place between the time that the system is activated with the purpose of flight and the time that the system is deactivated at the conclusion of its mission—and in which any person suffers death or serious injury, or in which the aircraft has a maximum gross takeoff weight of three-hundred-pounds or greater and receives substantial damage.
At the time this definition was valid, the weight-based requirement was necessary because defining an accident solely by “substantial damage” would have required investigations of numerous small UAS crashes with no significant safety issues. Consequently, there was no legal requirement to report or for the NTSB to investigate events involving substantial damage wrought or incurred by unmanned air vehicles weighing less than three-hundred-pounds—on account of such events not being recognized as “unmanned aircraft accidents.” While the old definition ensured that the NTSB expended resources on UAS events involving the most significant risk to public safety, the advent of higher capability UAS applications—such as commercial drone delivery flights operating in higher risk environments (e.g., populated areas, beyond line-of-sight operations, etc.)—has prompted the agency to update the definition of “unmanned aircraft accident.”
A substantially damaged, small, delivery-drone may bring to light significant safety issues, the investigation of which may enhance aviation safety through the independent and established NTSB process. By amending the definition of “Unmanned aircraft accident,” the NTSB is empowered—obligated, in fact—to treat certificated unmanned air vehicles in the selfsame manner as manned aircraft, and in the wake of accidents involving such, immediately investigate, influence corrective actions, and propose safety recommendations.
Accordingly, the new definition will retain a degree of flexible to account for changes in the UAS industry. Only by anticipating changes in UAS technology and applications will the NTSB retain its ability to respond quickly to UAS events with safety significance, while not burdening the agency or public with unnecessary—and costly—responses.