A new study by the US Federal Aviation Authority has shown that there is a risk of severe structural damage to aircraft due to drone strikes, which is much greater to comparable air strikes.
The computer simulation study also showed a risk of fire if a drone battery penetrates the aircraft exterior due to a collision and then ignites.
The study was conducted by the Alliance for System Safety of UAS through Research Excellence (ASSURE), a group of 23 research institutions and universities and industry and government partners.
The extensive simulations tested 140 scenarios of a fixed wing and quadcopter drone, with weight varying from 1.2kg to 3.6kg, hitting different surfaces on both a commercial airliner and a smaller business jet. Impact velocities ranged from 100 knots to 365 knots.
In all scenarios, there was greatest risk from a fixed wing drone hitting the tail fins or rudders of the aircraft and causing structural damage. is comprised of twenty-three of the world's leading research institutions and more than a hundred leading industry/government partners.
There was also a fire risk from a quadcopter drone battery penetrating an aircraft's tail and causing a fire if the battery was damaged.
On the business jet model, the windscreen was identified as another weak spot.
Tests on engines found that the most dangerous situation was a drone hitting turbine blades on take-off when the engine revolutions are highest.
Drones were modelled on two commercially available models, DJI's Phantom 3 Standard quadcopter and the fixed-wing Precision Hawk Lancaster Hawkeye III.
The study attributed the greater risk of damage in comparison to bird strikes with similar weights and velocities to solid drone components such as batteries and motors, which could do more damage than a bird.
The ASSURE study concluded that although there is some risk of severe structural damage, even lower levels of damage are likely to be costly in terms of repairs and down time for aviation operators. The report suggests that drone makers should develop detection and avoidance systems as the first means of defence, but could also consider including energy absorbing components or materials in drone construction to minimise the damage of impact.