Is 5G dangerous for air transport?

The arrival of 5G is creating a lot of turbulence in the world of air transport, as it would cause interference that could jeopardize flight safety. As a result, many flights have already been cancelled for this reason, and some aircraft are more vulnerable than others.

We’re here to help you make sense of the situation and understand whether there really is a risk.

5G creates a lot of turbulence

Several weeks ago, you no doubt heard the media report on the many 5G-related concerns that led to a cascade of flight cancellations.

In January, a number of airlines (including Emirates, ANA, Japan Airlines…) cancelled all or part of their flights to the USA, where 5G deployment was about to begin. The reason for the panic: a warning from the FAA (the federal aviation authority) that 5G would cause interference with aircraft altimeters, prompting it to ban automatic landing and instrument flying around 100 airports. At the same time, a Boeing alert announced that the B777 was specifically affected and should not be used in these conditions.

The situation returned to normal, at least temporarily, when local telecom operators temporarily agreed not to deploy 5G antennas near airports.

But last week the FAA once again sounded the alarm, issuing a new airworthiness directive, this time concerning B737s. According to the agency, the frequencies used by 5G cause interference with the radio altimeters on all aircraft of this type except 737-200s. Given that the 737-200 has not been produced since 1988, let’s say that the entire fleet currently in operation is concerned.

What’s wrong with radio altimeters and 5G?

In all cases, it’s the radio altimeters that are the problem. The radio altimeter is a device that measures the distance between the aircraft and the ground. It emits a wave towards the ground, which reflects off it, returns to the device and the time taken to return is used to determine the distance it has travelled, i.e. the distance between the device and the ground.

This equipment is essential for piloting an aircraft, especially in low-visibility conditions, as it’s the only way for the pilot to know how far he is from the ground.

It’s important to understand the difference between a radio altimeter and a traditional barometric altimeter. It measures the difference between the atmospheric pressure at the aircraft and that at a reference level, to deduce the aircraft’s altitude. This reference level may be sea level or airport altitude, which is known to the pilot.

The barometric altimeter therefore determines altitude in relation to the runway, but not distance from the ground. This difference is essential if, for example, a mountain is in the path of the aircraft’s descent: the aircraft may be at a comfortable altitude in relation to the runway, but dangerously close to the mountain. This suggests that airports where the FAA has banned automatic landing have a specific runway centerline relief.

But back to the radio altimeter, it emits waves at a certain frequency, very close to that used by 5G antennas, which can mislead on-board equipment.

Is 5G dangerous for air transport?

Aside from the sensationalism of the various announcements and flight cancellations, the question passengers have to ask themselves is whether the widespread deployment of 5G puts their safety at risk when traveling by air.

Without setting ourselves up as aviation safety specialists, we can say that :

1°) The presence of 5G antennas near an airport only arises in the case of instrument flying.

2°) Not all aircraft are affected. As a result, the FAA has begun to “certify” certain models of radio altimeters.

3°) The problem really only exists…in the United States.

And that’s where we should have started, to spare you the tedious reading that led you here but certainly improved your general knowledge of the subject.

Europe and France take a cautious approach to 5G

If you’ve noticed that all the above examples come from the USA, it’s not because the density of traffic makes it a representative sample of the world’s air transport, but because although it’s had time to prepare U.S. operators and regulators took the subject rather lightly compared with their European counterparts.

To start with the frequency used for 5G in Europe is slightly lower than that used in the USA. Enough to reduce the risk of interference.

In addition, depending on national legislation, European countries impose antennas that are either further away from airports, less powerful, or pointing downwards.

For example, in France, the Agence Nationale de Fréquences (yes…we have national agencies for just about everything…) has imposed that antennas at 17 airports must be oriented opposite the flight path of aircraft.

The problem was therefore known historically and everyone had time to prepare to deploy 5G with the highest level of safety. Some have simply treated the subject with a lightness that could be described as culpable.

In any case, with the replacement of older radio altimeters by more recent models that take 5G’s specific features into account, the subject should soon be a thing of the past.

Meanwhile, despite pressure from local lobbies, US airports are still deprived of 5G for an indefinite period, which we hope will be as long as necessary for safe operations.

Bottom line

The frequency used by 5G may cause interference with aircraft radio altimeters. This issue having been known for a long time, many countries have taken the necessary steps to secure airport approaches and make traffic safe. Not the United States.

Image : aircraft and 5G antenna by Steve Heap via Shutterstock