This week’s newsletter is arriving a day early. For those in New York for our meetings or the holiday receptions, I hope to catch up with you later today in person.

I’m sure you’ve heard the story by now. On October 30, a JetBlue A320-200 operating from Cancun to Newark experienced a software error at 35,000 ft while on autopilot, causing the aircraft to descend. The pilots took manual control and landed the airplane in Tampa with 15 people injured.

Engineers at Airbus rushed to diagnose the problem that caused the false angle-of-attack readings, which resulted in the aircraft automatically pitching down (sound familiar?). EASA issued an Emergency Airworthiness Directive effectively grounding any A320 family aircraft (to include the NEO) until a software patch for the Elevator Aileron Control (ELAC) unit could be fixed. That fix included a rollback to a prior version.

Immediately after the Emergency AD was issued by EASA and other agencies around the world, Airbus quickly put out a press release apologizing for the disruption and explaining the reason:

“Analysis of a recent event involving an A320 Family aircraft has revealed that intense solar radiation may corrupt data critical to the functioning of flight controls.”

Here’s the idea: 2025 is an intense year for solar radiation. This aircraft was at a high altitude, where solar radiation impacts are much higher. The intense solar radiation triggered a rogue electron to fire in the ELAC, resulting in the upset. The software wasn’t robust enough to handle this specifically intense radiation event.

Only… there was no event. There was no flare. In fact, radiation activity was remarkably low during that period.

Dear studious reader of Aviation’s Week in Charts, I invite you to follow me down the solar flare rabbit hole I’ve been in for the past week. Hang on tight. It gets wonky.

Flare hunting

Solar flares happen. In fact, we are coming off a peak in solar flare activity during the latest solar cycle. The chart below shows radiation events that have hit Earth’s atmosphere, as detected by the GOES satellite network.

What we are specifically looking at are S-Scale (or G-Scale) events of proton flux. Why are we looking at proton flux? Because it is what arrives from the sun that can potentially disrupt electronics. We’re not talking about the X-ray flare that delivers electromagnetic radiation and often disrupts radio frequencies and even GPS accuracy. We are talking about high-energy protons traveling from the sun to Earth, penetrating the Earth’s protective magnetic field, and also penetrating the aircraft’s hardware shielding to deliver what’s called a Single-Event Upset (SEU). Another term you may have heard for it is a “bit flip”.

These protons could take hours or even days to reach Earth after a major solar event, meaning the impact on Earth may not be felt precisely when the flare occurs. X-ray flares could mean a proton event is inbound, or not. It’s important to know that NOAA tracks both X-rays and proton flux. X-rays travel from the sun at the speed of light, hence the early warning, while protons take the local train.

The proton flux usually arrives associated with a solar flare, but not always. Sometimes the sun just sends a little gift on its own. There may not be an X-ray warning of the inbound protons in that event; however, we would still detect the arrival of the proton flux. Point being, using the various measurements from NOAA, we can precisely determine what hit the Earth and could impact electronics. If there were a flare with no proton flux, we would see the X-rays, then not detect the protons (or electrons). If there were a flux of protons that hit us without any X-ray warning, we would see that when it arrived.

The chart above shows just how spiky these proton events can be. NOAA knows when they hit. It’s quite obvious when they do. And these events happen. Not routinely, but also not something we would necessarily call rare. In fact, Earth withstood a sizeable payload of protons from the sun on November 12th. Author’s note: No airplanes pointed themselves at the ground that we know of on November 12th.

The standard way to view the same spikey data is to use a logarithmic scale. That’s kind of how space works. When it goes, it goes big, so we adjust the Y axis to better show events in powers of 10.

If you squint, you can see the peak of Solar Cycle 25, which is the cycle we are currently on the back side of. The recent storm on November 12 was significant, but still at lower intensities than we’ve experienced during the past year. NOAA provides a 10 MeV threshold to indicate when it deems the proton flux as being able to penetrate standard electronic shielding. Airplanes are designed to handle far more proton flux than standard.

The November 12th event started on the 11th, arriving in a few waves and peaking mid-day on the 12th before gradually falling off. This is the impact of a solar flare - an intense radiation event.

It happened. Between November 11th and November 13th, the Earth was subjected to an intense level of proton bombardment not experienced since October 2024. No aircraft anomalies were reported (that we know of), and no ELAC units decided to pitch down.

(However, the storm on the 12th did not arrive without consequence. In fact, one of the year’s major events happened on November 12th - the U.S. government ended the shutdown. Correlation is not causation, but maybe these radiation storms aren’t all bad.”

Now, let us take a look at October 30, 2025, and the days leading up to the “intense solar radiation” that Airbus referenced as the potential issue in the JetBlue upset.

I’ve never been so interested in such a boring chart. Nothing happened. There was no intense solar radiation. In fact, that period was abnormally quiet (though we’re talking slightly quieter than silent).

Even looking back a week for any stray protons from an earlier storm arriving late (the flight was destined for Newark, after all), there just weren’t any. Nothing happened. We looked at X-ray events, electron flux, the displacement of the magnetic field… all quiet.

What does this mean?

A few possible explanations. We’ll start with the easiest:

1. Perhaps we’re missing something.

The first rule in data analysis is to know what you don’t know. Space is a big place. We aren’t astrophysicists. Maybe we’re missing something.

My personal experience with proton flux data dates all the way back to last weekend. We have identified serious flaws in articles published since the grounding, such as directly attributing the phantom radiation storm to a specific sunspot. Upon further research, that sunspot arrived and concluded in October 2023, not 2025. Nobody seems to have questioned it, but the same is not lost on us: we don’t know what we don’t know.

2. Airbus was incorrect in its assessment of what could have caused the SEU

This scenario is interesting. Neither the EASA report nor the FAA report referenced solar radiation; both cited a software malfunction. In fact, the source of the solar flare theory seems to be from Airbus’s press release, where the company said the radiation “may corrupt data critical to flight controls…”

To me, this sounds like the result of a game of telephone in a large company. The following conversation is how I see it potentially playing out in my own head. It is entirely made up - imaginary - and how things like this can happen.

Management: “What happened?”

Engineers: “The software went bonkers (technical term), and people got hurt.”

Management: “Why?”

Engineers: “Well, boss, we see where the software told the airplane to be level, then we see where it told it to point down.”

Management: “Ok, why?”

Engineers: “The software received erroneous data from two sources at the same time… yadda yadda yadda… point nose down.”

Management: “Why did it receive erroneous data from two sources?”

Engineers: “It happens.”

Management: “What happens?”

Engineers: “Erroneous data.”

Management: “WHY!?!”

Engineers: "I mean, it could be anything. A solar flare could do it.”

Management: “Perfect, thanks.”

Engineers: “But, I’m not sure if there even was a…”

Management: “Thanks, we’re good for the press release.”

For the record, we know this conversation did not occur exactly like this; It was probably in French.

Jokes aside, there is nothing underhanded about this. It’s just how the game of telephone works when complex issues are moving quickly. We naturally want to know what happened, what caused it, and why it won’t happen again. “Because a bit flipped” doesn’t cut it in many of our minds.

Or maybe there is another, equally benign explanation.

But this raises the next question: Why did the ELAC on a JetBlue A320 abruptly pitch down at a rate that injured 15 people? Because, unless we’re missing something, it wasn’t a solar flare.

Research published this week

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