While reports of drones near airports are increasing in the United States and Europe, for the moment every drone impact on an airliner has resulted in a little crumpled sheet metal. Airliners have been designed to withstand bird strikes much more frequently than pseudo-contacts with UAVs, but will they be able to withstand collisions with UAVs that will inevitably occur in the future? A scientific study commissioned by the FAA (Federal Aviation Administration) and the Alliance for System Safety of UAS through Research Excellence (ASSURE) has accurately assessed the damage of a drone on an airliner. Initial results could lead to tighter aviation regulations.
DJI Phantom 2 vs. Boeing 737: what damage?
Everyone is familiar with the famous chicken barrel test, where a dead chicken body is pulled from the windshield of an airplane to make sure it is resistant. Such tests do not yet exist with drones, but this may well be necessary in the near future.
The work of the ASSURE research team began in 2016, with researchers and resources from the universities of Mississippi, Montana, Ohio and Wichita. The study is particularly extensive and complete because it combines laboratory tests and computer simulations. The researchers wanted to verify the damage caused by the impact of a Phantom 2 DJI quadcopter and a PrecisionHawk fixed-wing drone on multiple parts of a Boeing 737, as well as a Learjet 31 business jet.
Researchers have accurately modelled UAVs and their various components, including engines and batteries, the most dangerous parts of a drone and projected them virtually dozens of times on 3D models faithfully reproducing the coating of the airliner and business aircraft, as well as their internal structure and engines.
Over 180 drone impact on airliners simulated
The 180 virtual crashes carried out in twenty months have made it possible to establish that the impact of a drone has a higher overall energy than that of a bird but that this energy varies according to the dynamics of this collision, i. e. the angle and speed at which it hits the plane, but also the design of the drone itself. Simulations have shown that collisions with drones inflict more damage than collisions with birds. While current aircraft are designed to withstand the impact of a 4 kg bird on the empennages and 2 kg on the windshield, these tests could lead to an upward revision of these requirements. As for the drone batteries, suspected of potentially triggering a fire in the event of a drone impact, researchers have shown that if the impact occurred at high speed, there was no risk of fire, however, if the impact occurred at low speed, i. e. at the time of take-off or landing, the battery could actually remain blocked in the airframe and, as a result, the battery could become blocked in the airframe.
The work of the ASSURE research group is continuing, with tests to be carried out on modern aeroclub aircraft, helicopters and turbojet engines. Initial findings could provide the FAA with arguments to strengthen the UAV regulations and perhaps also reinforce the design constraints for airliners.
“FAA and ASSURE Announce Announcements Results of Air-To-Air Collision Study”, Press Release, November 28,2017
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