100% for electronics operating at altitude. Also on the ground, but we mostly act like it doesn't happen and are usually ignorant of the root cause when it does.
EMI causing bugs is the equivalent of "bad juju".
It was apparently added in a later HW revision
"The LTN-101 ADIRU’s CPU module was later redesigned to reduce costs and to include error detection and correction (EDAC). EDAC is used for detecting and correcting single-bit errors in RAM chips to give protection from single event effects (SEEs, see section 3.6.6). This change was a significant redesign and resulted in a new CPU module part number (466871-01). The EDAC was performed by a new ASIC, and all of the RAM chips used on the CPU module were replaced with a different chip.13"
https://www.atsb.gov.au/sites/default/files/media/3532398/ao...
"There was a limitation in the algorithm used by the A330/A340 flight control primary computers for processing angle of attack (AOA) data. This limitation meant that, in a very specific situation, multiple AOA spikes from only one of the three air data inertial reference units could result in a nose-down elevator command. [Significant safety issue]"
It's the only one marked "Significant safety issue" so my money is on that.
The ELACs (controlling the elevator and aileron actuators according to the demands computed by other functions) are made by Thales specifically for this aircraft type and probably have a quite different design.
I suggest trying to fly with a Geiger counter. At the cruise altitude you have something like 15-20x the normal background level, when flying over the pole it can rise to 30x.
It's actually not caused by the solar radiation, it's too weak to reach the flight level. It is caused by cosmic rays, and the solar activity modulates how much of the cosmic radiation reaches the lower levels of the atmosphere.
Radiation should be covered under normal safety, along with they already shield for it.
People often wrongly blame things on radiation, bit flips etc. when they don't know the real cause. A well known pattern.
There is a Hacker News item that was on high repeat where they eventually they solved the ~'cosmic radiation bug' as they first called it. Cannot remember the link.
It will not be true no matter what the, I know 'interesting' facts, 'I have a wiki link', crowd tell you. Real life is boring (and amazing). See Heisenbug's - https://en.wikipedia.org/wiki/Heisenbug
From https://www.airbus.com/en/newsroom/press-releases/2025-11-ai...:
This is different from the core claim that the incident was caused by radiation. What are the prior probabilities that the system was exposed to "intense radiation"? Vs some other mundane cause such as a faulty wire or mechanical issues? And what is the evidence supporting the former hypothesis?