Aviation delays ease as airlines complete Airbus software rollback
- Reference: 1764566023
- News link: https://www.theregister.co.uk/2025/12/01/a320_software_rollback/
- Source link:
This story starts on October 30th, when flight 1230 operated by US airline JetBlue made an unplanned diversion to Florida’s Tampa International Airport, interrupting its journey from Cancun to Newark. According to a US Federal Aviation Administration [1]statement , “the crew experienced a flight control issue.”
At the time, CNN [2]reported the plane experienced “a sudden drop in altitude” that caused injuries to around 15 passengers. ABC News [3]reported “up to 20” injuries.
[4]
In the following days and weeks, the incident seemingly faded into history – until November 28th when Airbus published a [5]press release that opened “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.”
[6]
[7]
The same day, the European Union Aviation Safety Agency (EASA) [8]published an Emergency Airworthiness Directive to address “an issue which manifested itself in an event on JetBlue flight 1230 on October 30, 2025.”
The [9]Directive [PDF] explained the incident as follows:
An Airbus A320 aeroplane recently experienced an uncommanded and limited pitch down event.
The autopilot remained engaged throughout the event, with a brief and limited loss of altitude, and the rest of the flight was uneventful.
Preliminary technical assessment done by Airbus identified a malfunction of the affected ELAC as possible contributing factor.
This condition, if not corrected, could lead in the worst-case scenario to an uncommanded elevator movement that may result in exceeding the aircraft’s structural capability.
The “ELAC” mentioned above is the elevator and aileron computer that drives the elevator, a hinged flap on the trailing edge of the horizontal stabilizer – the aerodynamic surfaces that look like little wings at the back of a plane.
Horizontal stabilizers are effectively upside-down wings because they create downward pressure to balance the lift created by the main wings. Elevators vary the amount of downward force to help push a plane’s nose up or down
[10]
Whatever was wrong with the ELAC meant the elevators pushed Flight 1230’s nose down, sharply and suddenly.
Remember the phrase “exceeding the aircraft’s structural capability” above? That means Airbus found the ELAC could move the elevators in ways that could break the A320.
Which is why Airbus, EASA, and other aviation authorities ordered a fix of all A320s with the problem, ASAP.
[11]
“These measures may cause short-term disruption to flight schedules and therefore inconvenience to passengers,” the EASA stated.
That’s an understatement because Airbus identified around 6,000 planes that need the fix.
Fixing an ELAC
Fixing the ELAC required rollback of a recent Airbus software update.
Industry sources tell The Register that the procedure required about three hours of work.
Airlines around the world scrambled to make the fix, but many couldn’t avoid delays to their schedules. One reason for those delays was that the equipment to install the software wasn’t available at every airport, a situation the EASA acknowledged by allowing airlines to fly planes without passengers to a location where they could do the necessary work.
A320 pilot Arjun Singh has [12]identified the problematic software release as “L104” and said the rollback was to version “L103+”.
Left unexplained, for now, is exactly how intense solar radiation corrupts data.
That radiation can impact comms is not in dispute: Solar flares disrupt communication on Earth and in orbit. The Register has seen theories suggesting that L104 may not have recognized data corrupted by solar radiation and the ELAC therefore acted on bad data and issued erroneous and dangerous instructions.
Airbus CEO Guillaume Faury has [13]apologized for the mess.
“The fix required on some A320 aircraft has been causing significant logistical challenges and delays since yesterday,” he wrote on Sunday. “But we consider that nothing is more important than safety when people fly on one of our Airbus aircraft - like millions do every day,” he added.
Faury also surely realized that this incident shared many characteristics with the 2018 and 2019 crashes involving Boeing 737 Max aircraft, in which faulty software was found to have caused hundreds of deaths. Boeing’s [14]reputation remains stained by that incident, as does its balance sheet and share price.
At the time of writing, FlightRadar24 [15]reports major delays in some parts of the northeast USA. Things may yet worsen as The Register finished this story at around 05:15 UTC on December 1st, a quiet time for commercial aviation. ®
Get our [16]Tech Resources
[1] https://www.faa.gov/newsroom/statements/accident_incidents
[2] https://edition.cnn.com/2025/10/30/us/jetblue-flight-emergency-landing-florida
[3] https://www.facebook.com/watch/?v=804880619012774
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aS11TIRBn8Uq5xDo8oeWGQAAAAs&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[5] https://www.airbus.com/en/newsroom/press-releases/2025-11-airbus-update-on-a320-family-precautionary-fleet-action
[6] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aS11TIRBn8Uq5xDo8oeWGQAAAAs&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[7] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aS11TIRBn8Uq5xDo8oeWGQAAAAs&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[8] https://www.easa.europa.eu/en/newsroom-and-events/news/easa-issues-emergency-airworthiness-directive-airbus-320-family
[9] https://ad.easa.europa.eu/blob/EASA_AD_2025_0268_E.pdf/EAD_2025-0268-E_1
[10] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aS11TIRBn8Uq5xDo8oeWGQAAAAs&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[11] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aS11TIRBn8Uq5xDo8oeWGQAAAAs&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[12] https://x.com/chainsawrocks/status/1994784339784339555
[13] https://www.linkedin.com/feed/update/urn:li:activity:7400488852299259904/
[14] https://www.theregister.co.uk/2025/01/15/boeing_airbus_commercial_deliveries_2024/
[15] https://www.flightradar24.com/data/airport-disruption
[16] https://whitepapers.theregister.com/
Re: The mystery wrinkles
There is just more radiation at the altitude of a transcontinental flight. I suspect that this was a low probability event and the one flight got unlucky.
Re: The mystery wrinkles
Python etc? Absolutely not. Any software that goes anywhere near an aircraft must be deterministic and is very heavily evaluated to DO-178. Software that keeps the aircraft in the air receives the highest assurance level (DAL A) meaning every requirement and every line of code is scrutinised. I’m told POSIX C is ok for the lower assurance levels, but likely you’ll need an RTOS for the higher levels.
Re: The mystery wrinkles
I was also a bit mystified; as far as I could tell from the CNN report the incident was c 18:48UT on the 30th (from 13:48EST), although and (as you say) nothing shows on space weather live. Perhaps it was a radio-only flare, and thus would not appear on the GOES X-ray flux?
Re: The mystery wrinkles
Airbus would never confess to using vibe coding. Hell would break lose if they did
intense solar radiation
Ironic.
The same intense solar radiation that the flying punters want to lie out in when they reach the Costa Del Lobster.
Redefinition of airliners
Flying used to be fun.
Now it has become a depressingly frustrating and often unpleasent experience - yes I'm looking at you Manchester Airport Group and Ryan Air (and the like).
To rationalise that, I started thinking of commercial airliners not as aircraft, but busses with wings.
I think a new definition is in order - flying microwave ovens....
Re: Redefinition of airliners
@ITMA
Quote "Flying used to be fun.
Now it has become a depressingly frustrating and often unpleasent experience - yes I'm looking at you Manchester Airport Group and Ryan Air (and the like)". Unquote.
What has that got to with the subject of the article?
Re: Redefinition of airliners
And if you don't like ryanair, don't fly with them. I won't
Re: Redefinition of airliners
> I started thinking of commercial airliners not as aircraft, but busses with wings.
The US domestic airlines were already that in the 1980s.
Re: Redefinition of airliners
> To rationalise that, I started thinking of commercial airliners not as aircraft, but busses with wings.
Have you heard of this airliner called the... air bus? Seriously. They call it a bus that flies in the air. Who'd have ever thunk it.
I initially thought isn’t error correction done at the hardware level?
But maybe some crc check when transferring data. But I would have thought there would be multiple versions of the truth voted on.
Sounds like it was a screwed up patch for the initial problem, that has issues that may or may not be related to the initial problem.
I see many airlines saying “we are not affected”, wondering if that is because they don’t update very often.
It stands to reason they don't update very often. Imagine a flight using Microsoft software on Patch Tuesday needing a reboot at 20.000 feet up..
They don't.
Airlines don't update software very often. It's normally only done at regular scheduled overhauls.
The only time it's done ASAP is to correct a flight safety issue.
Installation is not trivial. There's a full audit trail of the state before the update, verification steps to ensure it actually occurred, and the state afterwards.
Even "normal" industrial software/firmware only gets updated during scheduled downtime, and generally only to correct specific known issues or add specific desired features. Downtime costs too much.
Re: They don't.
> Even "normal" industrial software/firmware only gets updated during scheduled downtime,
And indeed a lot has *never* been updated because of continuous processes. And then some bright spark decides to connect them to the interweb causing all sorts of exposure issues due to vulnerabilities and lack of patches. Not to mention zero day issues.
Something doesn't add up
"Left unexplained, for now, is exactly how intense solar radiation corrupts data."
Presents as a hardware design defect; fixed in software?
Re: Something doesn't add up
Not necessarily. For example, they may have incorrectly calibrated some algorithm to expect values from an instrument within a specific range - which is true 99% of the time, but such rare events may push readings outside the assumed boundary.
Re: Something doesn't add up
I believe unexpected accelerometer readings is what caused the schiparelli mars lander to think it was on the surface when it was a few miles above the surface, with the effect that it decided it no longer needed it's parachute
V-Model, HIL, Redundant Sensors
In theory, this kind of things can be avoided by running the control unit in realistic HIL tests. As mandated by the V-Model.
Sensor failure is part of proper HIL Testing.
Redundant Sensors detect Sensor failure.
HIL Testing can be done in front of a particle beam, which simulates the sun and other radiation sources.
One should think that well-educated and enlightened engineering managers could think of this and make the necessary time, money and machinery available.
Re: Something doesn't add up
The equivalent of switch debouncing: wait until the data is in a stable state before acting on it.
Then someone comes along and "optimises" the code - "why are we waiting here? Delete"
That's my experience anyway... I'll leave it to you to work out whether I was the one who wrote the initial code, or the one who sped it up.
Clearing Up Physical Mysteries
1.) Measure real-world radiation
2.) Talk to a particle physicist how to simulate 1000x the radiation in a lab
3.) Strap control unit with the real software in a HIL setup in front of artificial radiation source (linear accelerator or the like)
4.) See what the HIL reports.
5.) Change software and or hardware.
6.) GOTO 3.
It is almost as if we spend lots of money on CERN and almost if Airbus could cooperate with CERN on this matter. As both entities are funded mostly by EU states.
Details, Aerospace Software
It transpires:
1.) The problem was a bitflip, caused by solar storm radiation. For some hard to explain reason, the affected variable in main memory was not protected by CRC, ECC or the like.
1.2) Protection is ideally done by hardware, but can also be done in software: Store multiple copies of the variables and compare them upon each use. Handle deviation in a proper way.
2.) The affected software controls the horizontal control surface. This means the aircraft can potentially pitch up or down wildly, up to a breakup of the a/c structure.
3.) The software rollback again protects against solar storm particles.
Questions:
A) Shouldn't Airbus have found this problem in a HIL Test rig under simulated solar radiation ? Particle beam accelerators do exist and are not expensive for a fleet of thousands of aircraft. Needs to be done once for each release and all a/c
Note: Control systems of this kind are typically programmed in Ada, C, C++ and execute on a RTOS like Integrity-178, VxWorks, QNX or the like. Unixes or Windows do not fit the bill, as they are not hard realtime capable. CPU could be an embedded version of PowerPC, ARM or 680x0.
Re: Details, Aerospace Software
Note 2: software of this type is developed with the V-Model approach, which is vastly different from the quick-and-dirty approach used for most beancounting and general IT software.
See
https://di-fg.de/RobusteSoftware.html
Airbus does have a good history of faithfully executing the V-Model and this appears to be an unfortunate exception. Nevertheless, they should now subject ALL of their safety-critical control units to artificial particle beam while executing inside a HIL test rig.
compare with boeing
airbus- this COULD cause a very rare issue in the future, let's get fixed!!
boeing - we're told the average occurrence of this issue is once in 2 years so we'll leave it 2 years to fix the problem- HANG ON!! why did it only take 3 months for the next crash?! they said AVERAGE of two years!!
Well
This issue seems to expose a deficiency of current aircraft/spacecraft control unit development(HW+SW) processes.
Why did they not find it in a HIL test strapped in front of an appropriate particle beam(simulating a solar storm's radiation over several years) ?
I've added this subject to my document on these matters:
https://di-fg.de/RobusteSoftware.html
The intense solar flare origin probably come from another dimension -> https://www.airbus.com/en/sustainability/our-approach-to-sustainability/inclusion-and-diversity
This is why, when seated, you should have your seat belt buckled - even loosely. If you hit turbulence, or a super rare incident like this, you're less likely to be injured by hitting the ceiling or overhead lockers. It wouldn't stop you being injured by an unsecured idiot around you though.
If it's a Boeing I'm still not going.
The mystery wrinkles
I'm a bit puzzled by this as there were X-class [1]solar flares in the [2]first half of the year (Jan-Jun), but then nothing until November ... so the October 30 flight receiving "intense solar radiation" seems odd (could it really have been affected by the M4.8 flare of October 15?)
And also, which part of the software rollback fixes the issue ... something needed for ECC, something to do with the operation of lock-step redundant units, was the previous software update running Python or JavaScript with maliciously trojanized Shai-Hulud npm packages, vibe coding? It would be nice to get some clarity on this imho ...
[1] https://science.nasa.gov/blogs/solar-cycle-25/
[2] https://www.spaceweatherlive.com/en/solar-activity/top-50-solar-flares/year/2025.html