The threat of drones on the safety of civil aviation

On a warm, sunny mid-June afternoon, about 20 miles out from Logan International Airport and a half-mile in the sky, the pilot of a Jazz airline flight from Montreal on its final approach spotted a red-and-black object. It was a drone, and it was way too close. It missed colliding with the hurtling 50-seat plane by just 25 yards, according to a report filed with the Federal Aviation Administration. Such near-collisions between drones and planes are increasingly common.

Over the past few years, drones have become increasingly popular and accessible to a wide audience, with several million in use around the world. Although primarily used for recreational activities, drones are also increasingly used for commercial and government applications, including surveillance and security missions. However, the growing popularity of drones has also created concerns about civil aviation safety. The proliferation of drones has led to an increase in incidents involving drones and aircraft, endangering the safety of passengers and crew members. Given the explosion in the number of drones in use, and the lack of knowledge among remote pilots of the rules of the air and airspace, can we speak today of a threat to civil aviation safety from drones? How do the Civil Aviation Authorities take this new trend into account?

1) What is a drone or UAV ?

a) Definition and principles

A drone, or UAV (Unmanned Aerial Vehicle (UAV)), are aircraft able to fly and perform a mission without human presence on board. Flight instruction are given either by a remote control (that can be close to the drone, or thousand kilometres away), or by an electronic system that define the mission to be performed (for example, on small drone, an electronic system instruct the drone to land if the batteries become low). Therefore, there are two types of drones: those who actually require the assistance of a pilot on the ground, and those who are completely autonomous. The flight time autonomy may be extended to the operational decision-making to respond to any random event during the mission.

The principle of UAVs can be compared to that of the model aircraft, where small models are controlled by remote controls. However, piloting a model aircraft requires piloting skills, while those skills are embedded in the drone systems in such a way that a drone operator just has to give simple instruction (climb, descend …).

One may compare UAVs principle to that of missiles. The main difference is that a UAV can be retrieved and re-used, which is not the case for a missile.

b) Various design

UAVs design is not dictated by the necessity to house at least one pilot. Therefore, multiple possibilities exist to design a drone, and this will depend on the mission to be performed.

• Fixed wings (as on planes) or rotary wing (as on helicopters) can be used.
• Engines can range from a simple electrical engine to a sophisticated turbine engine.
• Airborne system can be more or less sophisticated, depending on the mission to be performed. The UAV can simply fly according to a remote control order, or be fitted with an airborne intelligence to perform its mission without assistance.
• The payload is one of the main elements of the UAV as it will allow performing the mission. Some drones can barely carry a small Go-Pro camera, other drones are able to lift and deliver a parcel weighting several pounds.
• Some UAVs are fitted with a power plant to produce the required energy to power onboard equipment.

2) History

During the Vietnam War, Americans have used drones (Firebee) to locate the launching sites of Soviet surface-to-air missiles "SAM-2": 3500 missions were identified. Later, in 1991, during the Gulf War, the USA used drones again (Pioneer) for day/night surveillance, target acquisition and artillery adjustment. British and French began to use the drones at this time.

For their part, the Israelis saturated air defences along the Suez Canal during the Yom Kippur War (1973) with a large number of cheap drones. Later they detected and "lured" by the same means the Syrian anti-aircraft batteries.

Experts believe that drones have really proved their operational capabilities for aerial observation (intelligence) on three major field of operations in former Yugoslavia, Iraq, and Afghanistan.

3) Use of drones

Originally used by the military, drones are now conquering civil field, and are used for multiple applications: dam inspections, harvest optimisation, water rescue operations, aerial photos and videos for movies or documentaries, surveillance of borders, surveillance of forest fires, surveillance of transport networks, parcel delivery, preventive triggering of avalanches, pest and parasite control.

4) The threat of drones on the safety of civil aviation

a) The consequence of an airborne collision between a drone and an airplane

The consequence of a collision between a drone and an airplane depends mainly on the weight of the drone, the type of airplane, and the zone of impact.

Commercial airplanes are designed to sustain a bird strike. A light drone (although it is hard, not like a bird) would make only light damage to an airliner. The aircraft will have probably to be repaired and checked before the next flight, but the consequence would be only financial.

A heavy drone could have dramatic consequences if it collides with an airliner. Impacting a metallic mass weighting several dozen of pounds at a speed of 150 kts could lead to severe damage and accident. One can easily imagine the consequence if the drone pass through the cockpit windows behind which the pilots are seated.

General aviation aircraft are more exposed to this risk. In addition to the fact that they fly lower (so closer the drones), their light structure could be damaged further to an impact with a drone. Also, as they are often fitted with only one propeller engine, the impact of a drone in the propeller will force the plane to an emergency landing without engine.

b) The regulation

The regulation is defined by each country. In this chapter, we will focus only on the USA and French regulation.

In the United States, regulations for recreational drones are set forth by the Federal Aviation Agency (FAA) and were put in place to ensure personal safety.

Every recreational drone owner must register online with the FAA and obtain a unique registration number for each drone they own. This has been mandatory since 2015 for any drone over 250 grams (regardless of the purpose of the flight). The registration number must be affixed to the drone to allow authorities to quickly locate the owner in case of an accident or incident involving the drone.

The flight rules for recreational drones in the United States are similar to those in France. Drones may not be operated above 120 meters in altitude and may not be operated near airports or other sensitive areas. Recreational drones must also be equipped with a warning light to improve their visibility.

In addition to flight rules, recreational drone owners must also respect the privacy of others. Drones must not be used to take photos or videos that could infringe on the privacy of those photographed.

If these rules are not followed, fines may be imposed. Fines can range from $1100 to $27500 depending on the severity of the violation. In addition, in the event of an incident or accident caused by a recreational drone, the owner of the drone may be held liable for damages caused.

FAA rules are constantly evolving in response to changes in drone technology. For example, the FAA recently implemented a new rule that all drones weighing more than 250 grams must be equipped with an obstacle detection and avoidance system to prevent collisions.

The rules for operating a recreational drone are:

• Fly only for recreational purposes (personal enjoyment).
• Follow the safety guidelines of an FAA-recognized Community Based Organization (CBO).
• Keep your drone within the visual line of sight or use a visual observer who is co-located (physically next to) and in direct communication with you.
• Give way to and do not interfere with other aircraft.
• Fly at or below FAA-authorized altitudes in controlled airspace (Class B, C, D, and surface Class E designated for an airport) only with prior FAA authorization by using LAANC or DroneZone.
• Fly at or below 400 feet in Class G (uncontrolled) airspace. Flying drones in restricted airspace is not allowed. Drone pilots should always check for airspace restrictions prior to flight on our B4UFLY app or the UAS Facility Maps webpage.
• Take The Recreational UAS Safety Test (TRUST) and carry proof of test passage when flying.
• Have a current FAA registration, mark (PDF) your drones on the outside with the registration number, and carry proof of registration with you when flying. Beginning September 16, 2023, if your drone requires an FAA registration number it will be also required to broadcast Remote ID information.
• Do not operate your drone in a manner that endangers the safety of the national airspace system.

source : FAA - FAA webpage about recreational drone usage

In France, French regulations applicable to recreational drones (the so-called open category) are issued by the French Civil Aviation Authority (DGAC) to ensure the safety of people and property when using these devices.

In 2023, in France, any owner of a recreational drone weighing more than 800 grams must register online on the DGAC website and follow a mandatory online training, to be authorized to use his drone legally. This training is free and allows to acquire the necessary knowledge to fly a drone safely, avoiding risks to people and property.

The registration of the drone allows the authorities to quickly find the owner in case of accident or incident involving the drone. In addition, registration allows the identification of drone owners who do not comply with the regulations in force.

In addition to mandatory registration, recreational drones must be equipped with a lighted warning device to improve their visibility and avoid collisions with other flying machines. This device is essential for flights at night or in low light conditions.

In addition, recreational drones may not be used above 120 meters in altitude. This limit has been set to avoid interference with air traffic and to prevent risks to the safety of people on the ground. It is also forbidden to fly a drone near an airport or other sensitive areas such as nuclear power plants and military zones.

The rules applicable to recreational drones in France aim to guarantee the safety of people and property, as well as the protection of the environment. Indeed, the use of drones can have harmful consequences on the fauna and flora. Therefore, it is prohibited to fly a drone over protected natural areas such as national parks or nature reserves.

Recreational drone owners must also respect the privacy of others. Indeed, the use of a drone to take photos or videos can infringe on the privacy of the persons photographed. It is therefore prohibited to film or photograph people without their prior consent.

5) Conclusion

If the pilot of an airliner will be unable to see and avoid a drone, the pilot of a light aircraft flying slower will be more likely to avoid a collision if he is able to see the drone in time, which remains definitely complicated. Whether for an airliner or a private plane, the consequences of a collision with a drone could be hazardous. The penetration of a UAV in a civil airspace without authorization represents a potential threat.

Complying with the regulation allows mitigating this threat. We can count on the professionalism of licensed operators that operate their drones in strict compliance with regulations. But the vast majority of drone’s holders are individuals, of which a substantial part seems to ignore the existence of laws on drones. And then there were deliberate illegal uses (about 80 recorded in France in 2015) which, added to incidents awkward uses, make the issue of security is becoming increasingly urgent.

Reducing the threat of drones over its airspace is an ongoing battle for Civil Aviation Authorities. This work will focus in the future on two areas: the adaptation of the regulations to simplify the industrial use of drones and better manage individual operators, and developing system to detect and neutralize the drones over flying sensitive sites.