Drones - Results of the mid-air collision study

With the news that the Department of Transport are seeking to introduce regulation, registration and technological solutions to better regulate the drone industry and use of drones, it may be that a small technical report passes those in the industry by.  However, the report commissioned by the Department of Transport, the Military Aviation Authority, and the British Airline Pilots Association, titled the 'Small and Military Piloted Aircraft Systems (drones) - Mid-air Collision Study' actually provides some interesting insights.

The reason that this study is so important is that, in comparison to bird strikes, the aviation industry does not yet fully understand the risk of drone collisions to aircraft. The study itself was conducted to obtain greater knowledge as to the damage a mid-air impact of a drone by an aircraft could have. Whilst some factors could not be replicated by the study, such as the aerodynamic pressure on aircraft and the low temperature of cruising altitudes, the study is clearly still a useful guide as to the risk drones pose to aircraft.

The recent rise of drone related Airprox reports (a situation where distance between an aircraft and another object is such that the safety of the aircraft may have been compromised) is testament to the fact that drones are becoming an increasingly common sight in our skies, and coming increasingly into contact with other air traffic.

The study found that for helicopter windscreens that were not bird strike certified, drones could penetrate through the windscreen at speeds well below cruising speed. These results were also applicable to general aircraft without bird strike certified windows. Fixed wing drones could even penetrate when the aircraft was stationary. In contrast, bird strike certified helicopter windscreens were more resistant. Quadcopter drones could penetrate at cruising speed and fixed wing drones below cruising speed. That said, neither could penetrate where the helicopter was stationary.  In addition, helicopter tail rotors were shown to be very vulnerable to all impacts with all types of drones. 

Thankfully, airline windscreens were far tougher. Severe damage and failure only occurred in testing where a large 4kg quadcopter was flown at high speed into the windscreen. In general then, smaller hobbyist drones were far less likely to damage an airliner than larger commercial drones.

The study also shined a light on to the fact that the construction of the drone is crucial as to whether it penetrates a windscreen, as even lower mass drones could cause more damage than higher mass drones where harder components like motors, batteries and metallic components were exposed and formed the point of impact.

This report is clearly invaluable in demonstrating that, as expected by the industry, helicopters are particularly vulnerable to a drone strike, even by drones of relatively low mass. Furthermore, even airline windscreens were not always sufficient to protect against drone strikes. 

The data obtained from the study has no doubt informed the Department of Transport's policy for the regulation and registration of drones, which will be discussed in a future article.

So how does all this affect drone operators? On the basis of the study, it should be obvious that even relatively light drones can cause significant damage to a wide range of aircraft, and therefore the actions taken by airports to ground aircraft where drones were in the vicinity do not appear as heavy handed as they might have done.

In the light of the fact that drones can cause severe damage to aircraft, drone operators should be aware of potential legal issues that a drone strike could cause. Not only would such an incident likely lead to criminal proceedings, but also a civil claim could be brought for the repair to damage done to the aircraft; this bill could potentially run into the tens of thousands of pounds.

Drone operators should be aware of this risk, and also review the Department of Transport's intended introduction of further regulation, registration and technology in relation to the use of drones in the UK, which are intended to make locating drone operators who fly irresponsibly an easier task, potentially thereby exposing the drone industry, and especially operators, to expensive and costly litigation where a drone is used improperly. 

Send us a message