Airbus A320 Fly by wire corrupted by radiation in flight(viewfromthewing.com) |
Airbus A320 Fly by wire corrupted by radiation in flight(viewfromthewing.com) |
> 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.
https://ad.easa.europa.eu/blob/EASA_AD_2025_0268_E.pdf/EAD_2...
This was the incident that triggered the investigation:
https://avherald.com/h?article=52f1ffc3&opt=0
https://edition.cnn.com/2025/10/30/us/jetblue-flight-emergen...
List of Airbus A320 family operators: https://en.wikipedia.org/wiki/List_of_Airbus_A320_family_ope...
Affected ELAC: Elevator aileron computer (ELAC) ELAC B L104
Serviceable ELAC: ELAC B L103+
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.
Apparently it has happened to an Airbus once before.
In practice, both approaches blend automation and pilot authority rather than strict philosophical extremes. And the practical difference at the controls is also not as extreme as some people think it is.
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.
From https://www.airbus.com/en/newsroom/press-releases/2025-11-ai...:
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.
[1] https://news.ycombinator.com/item?id=46083560
> On the Qantas 72 flight (2008), the ATSB report showed the same power spike that upset the ADIRU also left tidy 1-word corruptions in the flight data recorder. Those aligned with the clock cycle, shared the same amplitude and were confined to single ARINC words. That is pretty much exactly the signature of a failing solid state relay or contactor on the shared avionics power bus (upstream of both FDR and fly by wire).
> Radation-driven bit flips would be Poisson distributed in time and energy. So that is one way to find out("Apply this very expensive special tape from (e.g.) 3M here and here.")
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.
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
I begin to revise my opinion about LLMs. An LLM would not have misunderstood the comment that badly.
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...
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...
Thank you!
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.
EMI causing bugs is the equivalent of "bad juju".
They certainly do put a chapter with potential triggers down there, and it's a good take, you can't just discard the possibility. But above, they also have SW bugs as a potential trigger, so... Essentially, they don't know for sure yet.
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.
EDIT: On a deeper read, I am inclined to be a bit more charitable to this theory because, to my surprise: "As noted in section 3.5.2, the CPU module on units 4167 and 4122 did not incorporate EDAC"
I did not consider these units were _this_ old, so they did not have error correction on them. Nowadays, most every MCU has ECC on them. So, yes, without ECC the odds are quite larger that they DID get a "bit flip"
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.