Airbus A320 Fly-By-Wire Corrupted by Radiation in Flight
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Original: Airbus A320 Fly by wire corrupted by radiation in flight
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They also did extensive tests and analyses and came to the conclusion that a bug was highly unlikely (they would never say that something is impossible, but it still is exceedingly improbable).
> Essentially, they don't know for sure yet.
That’s not a really fair assessment. Their conclusion is that they could not estimate the likelihood of a radiation effect, so in that sense they don’t know for sure. But they still eliminated a lot of options. Almost all of them, actually.
Radation-driven bit flips would be Poisson distributed in time and energy. Because these corrupted bits are periodic and appear at the same word location every cycle, it does not appear to me to be caused by environmental radiation.
AMD has perform testing at data centers of different altitudes and there is some statistical significance in SRAM error rates. And that is typically only around 5000-6000 ft msl.
https://dl.acm.org/doi/10.1145/2503210.2503257
Planes are much higher than that in operation so get larger amounts of unfiltered solar flux.
This may be one of the causes of higher cancer rates in pilots, but eliminating other environmental causes may be difficult
https://www.cdc.gov/niosh/aviation/prevention/aircrew-cancer...
[1] https://news.ycombinator.com/item?id=46083560
https://avherald.com/h?article=52f1ffc3&opt=0
https://edition.cnn.com/2025/10/30/us/jetblue-flight-emergen...
https://www.airbus.com/en/innovation/digital-transformation/...
Obviously there no direct connection here, but it seems that destabilizing perfectly working aircraft could be the product of a culture shift.
A culture shift following a fad in the last couple of years that caused "a regression" (whatever you mean by that) in an aircraft that was made years before, and that was designed years before again? How would that work? They can stop selling aircrafts if they have a time machine.
I begin to revise my opinion about LLMs. An LLM would not have made misunderstood the comment that badly.
Apparently it has happened to an Airbus once before.
Original 1984 critical hardware: the box has an EEPROM module, you swap it on the plane.
FMS (which requires monthly nav data updates) and all modern hardware: the box can be updated over the ARINC 429 serial bus or Ethernet (newer systems/planes), called dataloading
Dataloading had different methods. A320s through the 2000's, most airlines had a 3.5 floppy disk drive on board (Airbus FDDU), and a mechanic fed floppies in. It was slow. Evolution of that was a USB port that took a flash drive.
Most current planes of older models just got rid of on-board dataloading. The mechanic uses a laptop with a cable or purpose-built tablet and plugs into a port. The mechanic can download the software via Wi-Fi or cellular onto the device: https://www.teledynecontrols.com/products/hardware-systems/p...
Airlines can indeed buy a on-board box that connects to Wi-Fi and LTE at the gate which downloads software. This is standard for the latest models that produce more data (A350, 787), but optional for older models. The mechanic still needs to go to the plane and push the buttons to tell it to load.
https://www.teledynecontrols.com/products/dataloading/eadl-x... https://www.teledynecontrols.com/products/hardware-systems/g...
Listen to yourself.
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?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".
Radation-driven bit flips would be Poisson distributed in time and energy. These corrupted bits are periodic and appear at the same word location every cycle. Does not appear to me to be caused by environmental radiation.
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.
> Before next flight after the effective date of this AD, replace or modify each affected ELAC with a serviceable ELAC in accordance with the instructions of the AOT. > > A ferry flight (up to 3 Flight Cycles, non-ETOPS, no passengers) is permitted to position the aeroplane to a location where the replacement or modification can be accomplished.
That's a very limiting AD. The "before the next flight" part is unusual, ADs often have a limit to the next inspection or X flight hours or similar, not immediately.
Anyone who knows anything about aerospace knows SEE is a known failure mode, it happens all the time because aircraft are exposed to cosmic rays at altitude. The manufacturers know and plan for this.
Trapping for every known failure mode can be difficult, however. It's a combination of hardware and software failing together.
Extensive testing is done to ensure you've covered everything but sometimes things are missed.
Airbus is much more transparent about its automation. Pilots even learn about the procedure to fly an A320 with a complete fly-by-wire outage using only mechanical emergency elevator controls and differential thrust.
Airbus is OK, but could be better. There is a long history of Airbus crews facing unexpected corner cases in their flight control laws, and fortunately only a few of them have had fatal outcomes. While there are only a few "major" modes, there are a surprisingly large number of edge cases that can be encountered.
In fact, the only way to get into direct law on a fully functional plane is to start pulling circuit breakers for the (redundant) flight computers and inertial reference units.
https://www.cnbc.com/2025/11/28/airbus-issues-major-a320-rec...