The European Cockpit Association (ECA), the representative body of European pilot associations, is calling for urgent action following the publication of the results of drone collisions tests with aircraft and helicopters.

The tests were performed as part of a study commissioned by the UK Department for Transport, the Military Aviation Authority and the British Airline Pilots’ Association to investgate the effects of a mid-air collision between small remotely piloted aircraft systems and manned aircraft.

The study — conducted by QinetiQ and Natural Impacts, using laboratory collision testing and computer modelling — comes in response to a steady increase in the number of Airprox incidents involving drones. There were six such events in 2014, rising to 29 in 2015, 70 in 2016 and 34 through the end of May 2017.

The authors note that the perceived threats posed by drones to aviation safety have been the subject of significant speculation but with minimal evidence-based substantiation. They describe their work as one of only a very small number of studies that directly addresses the topic of drone collisions.

The study aimed to find the lowest speed at collision where critical damage could occur to aircraft components. Critical damage was defined in this study to mean major structural damage of the aircraft component or penetration of drone through the windscreen into the cockpit. The study indicated that:

• Non-birdstrike certified helicopter windscreens have very limited resilience to the impact of a drone, at well below normal cruise speeds.

• The non-birdstrike certified helicopter windscreen results can also be applied to general aviation aeroplanes which also do not have a birdstrike certification requirement.

• Although the birdstrike certified windscreens tested had greater resistance than non-birdstrike certified, they could still be critically damaged at normal cruise speeds.

• Helicopter tail rotors are also very vulnerable to the impact of a drone, with modelling showing blade failures from impacts with the smaller drone components tested.

• Airliner windscreens are much more resistant, however, the study showed that there is a risk of critical windscreen damage under certain impact conditions.

• Drone components used can cause significantly more damage than birds of equivalent masses at speeds lower than required to meet birdstrike certification standards.

For the ECA, the results constitute a robust proof that drone impacts on aircraft windscreens and helicopter rotors can be catastrophic, even at relatively modest speeds with small drones.

The association is calling on national and European authorities to review the findings of the report as a matter of urgency and act to control the threat.