Fifth Generation Wireless Raises Issues for Airlines – Is the Concern Legitimate?

As 5G wireless networks become more widespread across the globe, is this technology a threat to the aviation industry? Dire warnings have come from the U.S. Federal Aviation Administration (FAA) and major airlines that claim 5G will interfere with aircraft electronics, specifically radio altimeters. The latest FAA directive claims the impact will cost passengers $1.59 billion annually because of delays, and materially disrupt operations at airports. The FAA has written to airplane and helicopter operators to alter their methods of operation in areas where 5G C-band broadband is live.

Why is this happening? Because the airlines are claiming that 5G cellphone frequencies will jam in-flight operations as the spectra of frequencies being used by telecommunications companies will interfere with those being used by onboard aircraft systems. The telecommunication operators call the FAA and airline companies’ concerns “fearmongering” based on disinformation, noting that 5G today operates in nearly 40 countries around the world without causing disruptions to passengers, airports and airplanes.

Aircraft use a piece of equipment called a radio altimeter. It operates using C-band radio frequencies and has been around for more than 40 years. The radio spectrum used is between 4.2 and 4.4 Gigahertz in the U.S. The spectrum for 5G C-band wireless ranges from 3.7 to 3.98 Gigahertz.

What does a radio altimeter do on an aircraft? It provides above-ground positioning data to the airplane during flight. The data is shared with onboard systems that provide terrain awareness, assistance to the pilot during takeoff and landing as well as to the autopilot when engaged. It provides wind shear data and alerts when flying close to the ground. For helicopters where the majority of flights are never that far above the ground, radio altimetry is critical to safe operations.

So how could a different spectrum range threaten the aviation industry? The fear is that airplanes will fall from the sky because the altimeters will be jammed or provide incorrect altitude readings.

Stories about wireless telephony doing weird things go back to the beginning of its introduction. Wireless signals from mobile phones were said to interfere with the operation of electric wheelchairs, hearing aids, and pacemakers. There were some reported incidents of radio interference from the phone network that caused a wheelchair to malfunction, hearing aids to buzz, and heart pacemakers to react to a cellphone when placed in a shirt pocket next to a person’s chest. But all of these issues were addressed quickly by manufacturers.

The current hysteria about 5G goes far beyond the airline industry. It includes conspiracy theories that 5G causes cancer, or is responsible for global warming. Unfounded and unfortunate, these ideas persist in an age where nonsense gets around the globe at Internet speed and over time is legitimized through retelling.

But the 5G hoo-hah from the aviation industry isn’t quite a conspiracy. It is more akin to the Y2K insanity that befell the planet as we approached the year 2000. A whole bunch of computer software companies warned us about a data field problem found largely in legacy mainframe computer software that operated for decades in large financial institutions, government, utilities, and manufacturing. The programs used two-digit data fields to indicate the year. So 1999 was entered as “99.” That meant all data records that followed when the year 2000 came around would register as “00.” Would that mean 1900 and if so would that compromise all the data records and databases recorded after 1900 on these systems? Would it cause software that used the date field for operational purposes to stop working?

Y2K software companies made a killing selling their remediation services to update legacy databases from a two to four-digit year. Not all did and when 2000 came, there were very few interruptions to services and operations around the world. Like the malfunctioning wheelchair there were a few incidents where a bank vault would not open, or an elevator not operate. But no elevator plunged to the ground. The banks’ vaults opened. And no airplanes fell from the skies.

Getting back to the story about radio altimeters. Their operation is determined by international convention. The 5G wireless spectrum bands are auctioned by nations or blocs like the European Union. Notification of spectrum band sales is posted for all to see well ahead of auctions. But like so many industries, the airlines are laggards when it comes to keeping up with technological changes that affect them. And in the U.S. it appears that the FAA has been paying little attention to telecommunications advances. So airlines haven’t considered upgrades to equipment that is mission-critical to airplane operations such as radio altimeters in the face of advances in wireless telephony.

Years after 5G auctions have sold spectrum ranges of concern, the airline industry has awakened to what may or may not be a potential problem. This is well after telecommunications companies have announced rollouts of their 5G wireless services, and after mobile phone manufacturers have introduced numerous 5G-compatible products.

The FAA has gotten involved since last summer, publishing presentations and studies that describe the problem that in some cases radio-based telemetry and equipment on airplanes might be compromised by C-band wireless signals operating at 3.98 Gigahertz. The FAA, as result, has requested of the federal U.S. government that deployment of 5G near U.S. airports be prohibited.

In Canada, where similar concerns have been raised the federal government proactively has placed restrictions on 5G-based telecommunications near airports even though the spectrum for wireless in the country is 3.5 Gigahertz, a far cry from the 4.2 to 4.4 Gigahertz frequencies used by airplane radio altimeters. Other countries have a much narrower safety net in place, as low as between 1.0 to 2.0 Gigahertz which these nations consider to be more than adequate to stop radio interference.

The Federal Communications Commission (FCC) had in picking the spectra to auction for 5G put in place a safety net to protect radio altimeter bandwidths. The 2.2 Gigahertz difference was seen as more than adequate.

So is this a real threat? Will airplanes fall out of the skies? If they do it will not be because of 5G wireless deployment but more than likely because of manufacturers like Boeing cutting corners with design flaws and bad software such as occurred in the Boeing 737 Max 8. And it will happen because the regulator, the FAA, doesn’t pay attention or do its job.

A final note: There is no standard for radio altimeters in how they operate including the equipment’s ability to work within a specified radio spectrum. It is pretty clear, where oversight by U.S. federal regulators is needed, it is decidedly wanting.