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expert reaction to media reports that departures at Heathrow were temporarily suspended (and have since resumed) as a precaution after a drone was sighted

Reactions to news of a drone sighting at Heathrow airport.

Prof Noel Sharkey, Emeritus Professor of Artificial Intelligence and Robotics at the University of Sheffield, said:

“The MoD purchased six Drone Dome systems from Israeli manufacturer Rafael in August 2018. These have 360 degree radars that can find and track a drone and bring them down or disrupt radio frequencies to jam communication between operator and drone. These should already have been in place years ago as the signs were all there.

“The new report on the future of drones published yesterday add some necessary and useful additions to the regulation of drones but they would have done nothing to help in the case of the current airport incursions.

“I am deeply concerned that even the counter-drone tech being purchased will not future proof our airports from drone attack. They will not be able to deal with systems where the operator is not in communication with the drone. There are many strong developments in the areas of drones operating using sensing systems.

“There is also a problem for these systems when there are multiple drones. As many as 100 or more can be released and operated by one person. We need to stop playing catch up and get ahead of the game.”

Lambert Dopping-Hepenstal FREng, CEng, FIET, FRAeS, Fellow of the Royal Academy of Engineering and Director at DH Future Systems, said:

Why are drones dangerous near airports?

“Aircraft are designed and tested to withstand collisions with birds, which are of known and unvarying composition.  Drones in contrast are of widely varying mass and composition, which makes the damage inflicted from collision with an aircraft far less predictable.  Drones are dangerous near airports because commonly available ‘hobby’ drones will easily reach an altitude that could bring them into conflict with an aircraft taking off or landing.   Even small drones represent a potential hazard at flying speeds near an airport.  They are equally a risk to low flying aircraft or rotorcraft such as air ambulances away from airports.

Why was this precautionary measure implemented; was it sensible?

“It was presumably an unquantifiable risk for which the only available mitigation is to suspend flying until this risk has been adequately assessed or a mitigation (i.e. disabling the risk in some way) has been successfully implemented.

What is current UK legislation about drone operation near airports?

“The legislation does not allow flying above 400 ft within 1 km of an airfield boundary although it was announced earlier this week that this is to be extended to 5 km for small drones (250g to 20kg).

Has anything changed since the Gatwick incident which might affect how this new incident is dealt with?

“Presumably some practical experience of what is and is not effective.

How much can we tell from the information currently available about why this might have happened?

“Drone operation falls into a number of quite distinct categories, which need different approaches:

“1. ‘Hobby’ operators that may inadvertently fly their aircraft into restricted airspace through ignorance of the rules (i.e. to get a more interesting picture) or through losing control of their aircraft.  This is partially mitigated by many ‘off-the-shelf’ drones having built in geo-fencing to prevent their operation in pre-programmed restricted airspace.  Not all will have this available.

“2. Commercial operators who are licensed and will have undertaken some training and should therefore be fully aware of the legislation.  These are unlikely to be the cause of the incursions.

“3. ‘Malicious’ operators who are intentionally flying in restricted airspace and who will have overwritten any software restrictions.

“In this instance it would probably be from either the 1st or 3rd group, although from the reported information most likely the 1st.

“We need to bear in mind that to harness the full benefit of this technology to society we need to find a safe way of manned and unmanned aircraft sharing the same airspace not simply applying greater restrictions.

“Both the Heathrow and Gatwick incidents illustrate the difficulty in verifying sightings and then identifying the level of threat to determine whether the drone(s) pose an unacceptable risk.”

Prof Martyn Thomas CBE FREng, Fellow and Emeritus Professor of IT at Gresham College, London, and Visiting Professor, Thomas Ashton Institute, Manchester University, said:

“Drones certainly present a safety hazard to aircraft. The degree of risk depends on the mass of the drone, the speed of the aircraft, where the drone hits the aircraft, and how much time and altitude the pilot has available to handle any damage to the aircraft. 

“This demonstration shows how much damage even a hobby drone can cause if the plane is flying fast:

“In December, the Daily Mail reported that a plane had been damaged by collision with a drone (with photographs)

“If a drone is ingested into an engine, it would be like a bird strike (or worse if it were a heavy industrial drone). That might cause a crash if the aircraft has just taken off or is about to land. Not every pilot is Chesley Sullenberger:

“There are legal prohibitions on flying drones too close to aircraft, or above 400 feet, or within 1 km of an airport boundary (, but these limits need to be stricter to ensure adequate separation between legal drone flying and aircraft – and enforcement is very difficult. Stricter laws have been promised following the problems at Gatwick.

“But malicious and illegal use of drones already occurs, including by terrorists:

“It is hard to see how aircraft can be adequately protected without affecting the legal use of drones (including use by the police and security services) and without interfering with GPS and other transmissions, which might cause other hazards.”

Prof Duc Pham OBE FREng, Chance Professor of Engineering, University of Birmingham, said:

“One cannot be too careful with this kind of matter and I support the closure of Heathrow while the drone sighting was investigated.  It seems that the lessons learnt from the Gatwick incident and any detection/protection system introduced since then have been effectively applied in this case, as the duration of the airport closure was much shorter than in the case of Gatwick.”

All our previous output on this subject can be seen at this weblink:

Declared interests

Prof Duc Pham: “I have no interests to declare.”

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