In today's Finshots we talk about how a screwup of epic proportions caused flight cancellations in the US last week

The Story

“Air India, Emirates cancel flights to the US.”

It was the big headline last week. And no, it wasn’t because of Covid. Instead, 5G was to blame.

Now 5G has been accused of all sorts of things. Cancer, tumours, infertility, baldness— The list goes on. However, this time around there might be some merit to the accusation. You see, 5G operations have already commenced in the US. But telecom companies need airwaves to really ramp up operations and when the US government made a portion of the C-Band available ( frequencies ranging from 3.7 to 3.98GH), there was considerable euphoria.

This band was once used to facilitate satellite television. But is now being repurposed for other applications. Applications like 5G. In fact, AT&T and Verizon lapped it up during the auction by paying $67 billion. It was a win-win for everyone involved.

However, just when you thought these companies would begin putting this spectrum to good use, the US aviation authority cancelled over 600 flights to the US last week, citing air safety concerns associated with 5G.

So what’s happening here?

Well, it’s kind of a long story.

So let’s start with the basics — radio altimeters. These are sensors onboard an aircraft capable of assessing the clearance height above terrain and other obstacles. For instance, it can tell you when you’re flying too low and avert a disaster. The altimeter, in this case, sends radio waves to the ground and receives some of them back after they bounce off the surface. It then measures the time needed to make the round trip and calculates the distance based on this information. That’s how most altimeters work. However, since it sends off a low energy pulse, the receivers have to be highly sensitive. And even though they operate in a fixed band that doesn’t overlap with the C-Band, they are susceptible to interference from these adjacent frequencies as well.

Now bear in mind, there is no one standard for how altimeters are supposed to be built. Different manufacturers have different needs and they design them based on these requirements. And that allows for variation. Variations where you have well-designed altimeters that can effectively filter spurious frequencies. And variations that don’t.

But according to one study commissioned by the aviation industry, it seems some aircraft are still equipped with altimeters prone to failure under certain “worst-case scenarios.” And when they fail, multiple aircraft systems, including collision avoidance systems, flight control systems and autoland systems will fail alongside it.

Now it’s not like people suddenly found out about this issue overnight. The US Federal Aviation Authority (the FAA) was privy to this detail. The US regulator for telecommunications (the FCC) knew of this issue. And the government agency  responsible for advising the President on this matter, NTIA, wasn’t exactly in the dark either. So why did it take until the very last moment for everyone to act?

Well, it’s complicated.

The administrator of the Federal Aviation Authority wrote a letter to the Trump administration back in December 2020, seeking a stay on the C-Band auction. The letter read — In the event that 5G network implementation moves forward without addressing these safety issues, the aviation industry needs a considerable transition period to develop updated radar altimeter performance standards; to design, manufacture, and certify new avionics; and then to integrate and install that equipment into aircraft and helicopters.”

However, the story goes that the letter never made its way to the telecommunications authority and the auction proceeded without a hitch after the FCC deemed that 5G did not pose a threat to commercial aviation. Meanwhile, the government agency that could have coordinated between the two parties, NTIA had its own share of problems. The head of the department had been axed earlier and there were several interim administrators trying to steady the ship.

At this point, the aviation authority, the FAA could have released a bulletin warning pilots and aircraft manufacturers about the supposed safety risks associated with 5G. Yet they waited until November 2021 to flag these concerns.


Well, we don’t know. Once again it seems that the US government failed to broker a peace deal between the FCC and the FAA. The telecommunications authority remained adamant that 5G did not pose a threat and the aviation authority wanted a stay on the rollout, altogether. And by the time the government intervened, it was already too late. The FAA now had the gargantuan task of certifying altimeters and figuring out alternative arrangements before the rollout on December 5th. This wasn’t going to happen. No way.

But since the newspapers had already gotten hold of this information, the onus was on the likes of Verizon and AT&T to act in the interest of the people. They could have simply set aside these concerns and commenced operations, but it would have forced the FAA to act on their behalf. The aviation authority would have had to impose restrictions on the movement of aircraft. Perhaps even ground entire airlines during the holiday season. And needless to say, the telecom companies would have been held responsible. So they voluntarily delayed the rollout by a month, but not before explicitly stating once again, that they didn’t believe 5G posed a threat.

However, despite this act of benevolence, the FAA still couldn't vet everything on time. Which explains why they had to impose restrictions nonetheless to make sure passenger safety wasn’t compromised.

So when will these restrictions go away?

We don’t know. For starters, you could try and swap out the incompatible altimeters with something more robust. But that will cost money. Money that airline companies are unlikely to put up. The government could ask the telecom companies to bear the expense since the C-Band is being repurposed for their benefit. But they have already spent over $100 billion to set up the 5G infrastructure. Getting them to pay more will be a tall ask. Another alternative is to build buffer zones around certain airports. In fact, this is what some European countries seem to have done. You could rework the antennas, 5G base stations and other equipment to make sure that they don’t interfere with airline operations. But this would also mean 5G wouldn’t be all that effective around airports.

So yeah, there are a few alternatives available, but compromises will have to be made. The only silver lining here? The regulators and the government finally seems to have recognised the massive fallout here, and are now working on a more permanent solution.

Until then…

Don't forget to share this article on WhatsApp, LinkedIn and Twitter

Also, at Finshots we have strived to keep the newsletter free for everyone. And we’ve managed to do it in large parts thanks to Ditto — our insurance advisory service where we simplify health and term insurance for the masses. So if you want to keep supporting us, please check out the website and maybe tell your friends about it too. It will go a long way in keeping the lights on here :)

PS: India is getting ready for its 5G rollout and authorities are already sounding reassurances suggesting that it won’t affect aircraft altimeters.