Small Remotely Piloted Aircraft Systems (drones) Mid-Air Collision Study
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This 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 has indicated that:

Non-birdstrike certified helicopter windscreens have very limited resilience to the
impact of a drone, 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:
─
It was found that critical damage did not occur at high, but realistic impact
speeds, with the 1.2 kg class drone components.
─
However, critical damage did occur to the airliner windscreens at high, but
realistic, impact speeds, with the 4 kg class drone components used in this study.

The construction of the drone plays a significant role in the impact of a collision.
Notably, the 400g class drone components, which included exposed metal
motors, caused critical failure of the helicopter windscreens at lower
speeds than the 1.2kg class drone components, which had plastic covering over their motors.
This is believed to have absorbed some of the shock of the collision, reducing the
impact.
5

The testing and modelling showed that the drone components used can cause
significantly more damage than birds of equivalent masses at speeds lower than
required to meet birdstrike certification standards.