When cellular phones were first introduced, power wheelchair users did not like them because if cell phone signals interfered with wheelchair signals, it could lead to terrible consequences for them. Within a short time, a solution was found to address all such concerns. A simple shielding technology was developed to prevent signal interference.

When mobile phones started to use international GSM digital standards, this time hearing aid users protested. Hearing aids designed for the analog world were faced with a new digital reality. The solution was in the simple updates that would adapt the hearing aids to the modern technology.

In the early years of the digital phone era, people living with pacemakers were also concerned. What if their cell phone signals interfered with the pacemaker signals that keeping them alive? As a short-term solution, doctors told their patients with pacemakers not to carry their cellular phones in their pockets close to their hearts. Afterwards, a shielding technology was developed again and the problem was solved.

Similar issue has appeared and is being discussed nowadays. US telecommunication operators are preparing to launch 5G service across the country on January 5th. The aviation industry is voicing its concern over the risk of this technology that may cause plane crashes. So, will 5G mean airplanes falling from the sky when it comes to our lives? 

IS 5G THE ENEMY OF AVIATION?

5G technology is defined as a next-generation mobile data service and network communication that will provide communication service at higher speeds and less latency via smart devices. In other words, we will be able to transmit very large files very fast with 5G. The quality of our voice calls will also improve significantly. 5G, the advanced level reached in mobile communication for now, has become one of the most important milestones of today's technology. However, it has been the subject of many conspiracy theories up until now. For example it was claimed that 5G mobile networks could interfere with signals from weather satellites in the neighboring frequency band and it was even claimed that it was the reason behind the Covid-19 virus.

The US Federal Aviation Administration (FAA) released a special information bulletin on November 2, on the risk of potential adverse effects of 5G technology on aviation industry.

(Special Airworthiness Information Bulletin – SAIB AIR-21-18)

With this bulletin, aircraft manufacturers, altimeter manufacturers, airlines and pilots have been warned against the possible effects of 5G on aircraft electronic systems. Two major communications companies AT&T and Verizon, taking the concerns of the FAA into consideration, agreed to delay the use of a new set of radio frequencies for 5G, which was supposed to be launched on December 5, 2021, to January 5, 2022.

As the date of January 5 gets closer, the FAA released two new airworthiness directives (Airworthiness Directive AD 2021–23–12 and AD 2021–23–13) at the beginning of December, raising the level of alarm over concerns that 5G signals could interfere with radio altimeter devices that measure aircraft’s altitude above the ground. In the presence of C-Band wireless broadband signals used by 5G technology, the Agency ordered the revision of flight manuals of aircraft and helicopters to prohibit certain operations requiring radio altimeter data. Thus, a new flight safety rule has been put into effect that prohibits pilots from using auto-landing and some other flight systems at lower altitudes.

This rule, which will affect dozens of aircraft manufacturers and thousands of aircraft, is thought to cause disruptions on some flight routes with low visibility conditions, where pilots must rely on the radio altimeter to land safely. The FAA says there is a potential risk that the 5G signals could lead to faulty readings that may make flying unsafe in these conditions. The FAA directives said the wireless broadband signals could create an “unsafe condition” unless immediate action before the January 5 deployment. That's why the FAA went beyond the ordinary process for the new rules it introduced. It directly enforced the new rules without any feedback from industry representatives.

PUBLIC SECURITY OR NATIONAL SECURITY?

The safety conditions of passengers on commercial and private aircraft are an unquestionably critical issue. But on the other hand, the United States does not want to fall behind in its technological competition with China, which has started to see the positive results of the expansion of 5G technology. For this reason, the potential problem that 5G technology will create in aviation safety has brought the concepts of public safety and national security in the United States.

Airwaves, also known as spectrum, is a common national asset subject to innovations brought by changing and transforming technologies. As technologies change, so do the assumptions in the spectrum-based environment. The necessity of redesigning products such as wheelchairs, pacemakers and hearing aids with developing technology is exactly about this subject. These products were designed according to existing realities. The new spectrum users have built a new world without any intention of harming such devices. In order for these devices to survive, they had to be redesigned.

FAA officials argue that things should be changed for a scenario where the use of 5G technology and aviation rules will co-exist safely. This is why the two airworthiness directives, enacted with an immediate action, are claimed to provide a framework for gathering more information to avoid potential impacts on equipment aimed at making aviation safer.

5G & RADIO ALTIMETERS

A radio wave emitted by the radio altimeter located under the airframe of the aircraft, which has a simple receiver and transmitter, hits the ground and it is reflected back up to the receiver. Calculations over the elapsed time and the length of the emitted radio wave determine how high the aircraft is from the ground (altitude).

In the frequency allocation table, which is allocated according to international rules, aeronautical navigation systems operate between 4.2 and 4.4 GHz. One of the main uses of frequency allocation in aviation is to transmit information over aircraft altimeters to facilitate computer assisted landings, especially below 2500 ft. The use of C-band spectrum used for 5G is authorized for between 3.7 and 3.98 GHz in the US. 

For this reason, aviation industry authorities are warning that 5G networks operating in the C-band have the potential to cause harmful interference to radio altimeters. Their concern is that the radios being used with the altimeter may not appropriately filter out signals lapping over from another part of the spectrum. 

In response, the FAA issued such rules for airlines and pilots to “be prepared for the possibility that interference from 5G transmitters and other technology could cause certain safety equipment to malfunction.”

Recently, the Canadian government has taken decisions to restrict the use of C-band at airports and ban the installation of 5G base stations near airports. Similar steps are also taken in Australia and France.

THERE IS NO ROOM FOR “POSSIBILITIES” IN AVIATION!

Two words are at the center of the FAA statements: The “potential” for interference and the “possibility” for signals to interfere with each other. However, decisions about the safety of air traffic are not based on assumptions such as the "potential" or "possibility", but on certain situations where all possibilities are eliminated.

Thus, a study was conducted by the Aerospace Vehicle Systems Institute (AVSI) simulating the worst-case 5G signal emission and its effect on aircraft avionics systems. In this study, it was concluded that there may be substantial differences in the receiver performance of radio altimeters from different manufacturers. This means that some altimeters are equipped with radio receivers with appropriate filters to protect against spurious emissions, while others allowed signals from outside the 4.2 to 4.4 GHz allocation to intrude. Many other companies have also conducted similar studies.

Subsequently, a guard band was created between the 5G spectrum and the spectrum in which the aircraft's avionics systems operate. Boeing’s proposal was to prohibit the use of 5G technology within the 4.1-4.2 GHz frequency range. Thus, the guard band developed to prevent interference was determined as a 220 MHz buffer between 3.98 GHz and 4.2 GHz, the highest frequency value of 5G.

The FAA emphasizes that manufacturers of radio altimeter equipment should continue testing for susceptibility to 5G interference and work on design changes that could minimize the effects of interference.

It is also strongly recommended that pilots remind passengers that all portable electronic devices equipped with 5G must be turned off or put into airplane mode during flight. This bandwidth is used seamlessly in 40 countries around the world. No other development is expected to occur in the US. For now, no proven study is available that 5G causes malfunctions as feared.

WILL 5G PROVIDE ANY BENEFIT TO AVIATION INDUSTRY?

It is for sure that 5G technology, which has the potential to create various problems for piloted systems, will provide great opportunities for the use of Low Altitude Airspace, that is to say the Unmanned Traffic Management (UTM). As 5G is increasingly defined by civil aviation regulators on a region-by-region basis, it will offer enormous advantages for autonomous drones or electric air taxis, which are expected to become an integral part of our lives in the near future.

When the concept of the Internet of Things (IoT) and 5G fully combine, a large number of objects or devices will be in communication with each other. This is a quite significant advantage in all areas of the aviation industry.

Almost all the stakeholders of the aviation industry, especially the airlines, airports and companies providing aircraft maintenance and repair services, have already started to make collaborations in order to incorporate 5G technology into their workflow processes.

Airlines will shift to a new understanding of in-flight entertainment. Saving weight with the new in-flight entertainment system will be possible, and all kinds of benefits will be offered to the passengers more easily and cost-efficiently. Thanks to instant access to movie and music platforms thanks to 5G, airlines will be able to offer a variety of services to satisfy their customers. In-flight messaging, communication, reading newspapers/magazines, and using the internet will seamlessly be achieved with 5G. Check-in processes will also be accelerated.

Flight crews will be able to easily manage passengers' food orders, control flight-related information, track connecting flights, and much more, with the tablets they use. They will even be able to check how many beverages are left in which service trolleys.

For example in February, Lufthansa Technik and Nokia deployed a 5G private wireless network for their Hamburg facility. This project enables virtual engine parts inspection where maintenance engineers in Hamburg can service customers in different locations. It will also be possible with 5G to train engineers all over the world through high definition videos.

In order to maximize the passenger experience at airports, projects are being developed that will use the combination of AI (Artificial Intelligence), from developing autonomous buses to security checks and all services at the terminal. With minimum human intervention, high precision and absolute security, 5G is thought to be one of the keys for a major transformation in aviation.

Thanks to the IoT, it is possible to instantly discover how many people are absent or who has not arrived yet from the passengers waiting to board. 5G technology is expected to support up to 1 million devices per square kilometer. Airport operations will also be managed in real time with 5G. Cooperation between airports, airlines, ground services and air traffic controls will be easier and more effective.

In addition, with the 5G, biometrically matching of passengers with their bags will be simplified. Lost luggage will be reduced. A seamless mobile experience will be achieved with Wi-Fi networks at airports. Rapid transmission and analysis of aircraft data will enable proactive aircraft maintenance and faster return to service and timelier take-offs. With the convergence of 5G and satellite communications, airplanes will be able to connect to all relevant systems. All stages of the flight can be monitored simultaneously from multiple centers.

With these modernized operations, airlines and airports will not only lower their costs, but also reduce their carbon footprint to achieve a more sustainable aviation industry.

To summarize, the potential problem that 5G will create for the aviation industry stems from the absence of a worldwide spectrum planning, that is, the lack of global standardization. It is certain that the 21st century will be remembered as the wireless century. Studies for 6G are currently being conducted in many countries. The way to keep up with the communication and technological requirements of the age is to set permanent strategies with a sound policy. The expectation across the world is to realize the scenario where 5G technology and safe aviation activities can coexist in the shortest possible time. And to achieve this, everyone has to do their part