> Wasn't the philosophy back then to run multiple independent (and often even designed and manufactured by different teams) computers and run a quorum algorithm at a very high level?

It was, and they did (well, same design, but they were independent). I quote from the report:

"To provide redundancy, the ADIRS included three air data inertial reference units (ADIRU 1, ADIRU 2, and ADIRU 3). Each was of the same design, provided the same information, and operated independently of the other two"

> Maybe ECC was seen as redundant in that model?

I personally would not eschew any level of redundancy when it can improve safety, even in remote cases. It seems at the moment of the module's creation, EDAC was not required, and it probably was quite more expensive. The new variant apparently has EDAC. They retrofitted all units with the newer variants whenever one broke down. Overall, ECC is an extra layer of protection. The _presumably_ bit flip would be plausible to blame for data spikes. But even so, the data spikes should not have caused the controls issue. The controls issue is a separate problem, and it's highly likely THAT is what they are going to address, in another compute unit.

"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]"

This is most likely what they will address. The other reports confirm that the fix will be in the ELAC produced by Thales and the issue with the spikes detailed in the report was in an ADIRU module produced by Northrop Gruman.

I don't know about the A320 but this was certainly the model for the Eurofighter. One of my university professors was in one of the teams, they were given the specs and not allowed to communicate with the other teams in any way during the hw and sw development.

EDAC is the concept, ECC is a family of algorithmic solutions in the service of the concept. Specific implementations of ECC are the engineering solution that implement the specific form of ECC in specific devices at the hardware or software level.

It’s confusing because EDAC and ECC seem to mean the same thing, but ECC is a term primarily used in memory integrity, where EDAC is a system level concept.

That was my initial confusion as well. It means exactly what you guessed, "Error detection and correction". The term is also spelled out in the report. I asked Claude about it (caveat emptor) and it said EDAC is the correct name for the circuitry and implementation itself whereas ECC is the algorithm. Gemini said that EDAC is the general technique and ECC is one implementation variant. So, at this point, I'm not sure. They are used interchangeably (maybe wrongly so), and in this case, we're referring to, essentially, the same thing, with maybe some small differences in the details. In my professional life, almost always I referred to ECC. In the report, they were only using EDAC. I thought I'd maintain consistency with the report so I tried using EDAC as well.

> Why would they be using flight computers from before 2002?

Because getting a new one certified is extremely expensive. And designing an aircraft with a new type certificate is unpopular with the airlines. Since pilots are locked into a single type at a time, a mixed fleet is less efficient.

Having a pilot switch type is very expensive, in the 50-100k per pilot range. And it comes with operational restrictions, you can't pair a newly trained (on type) captain with a newly trained first officer, so you need to manage all of this.

The issue detailed in the linked report details why the spike happened in the first place on the ADIRU (produced by Northrop Gruman). The recalled controller is the ELAC that comes from Thales. The problem chain was that despite the ADIRU spiking up, the ELAC should not have taken the reactions it took. So they are fixing it in the ELAC.

> Why would they be using flight computers from before 2002?

Why would you assume they're not? I don't know about aircraft specifically, but there's plenty of hardware that uses components older than that. Microchip still makes 8051 clones 45 years after the 8051 was released.

The neo is not brand new - it's an incremental update to the 320. neo refers to New Engine Option

> Why would they be using flight computers from before 2002?

Guessing that using previously certified stuff is an advantage

Because the problem isn't just this. It's that the flight controller did not properly decide what to do when the data spiked because of this issue as well.

My understanding is you're roughly right: the actuators will have their own microcontroller. It receives commands from the say 3 flight computers, then decides locally how respond if they mismatch. Ie for 2 out of 3 matching it may continue as commanded, but with only 1 out of 3 it may shift into a fail safe strategy for whatever that actuator is doing.

Voting can be coordinated between the N cpus rather than an external arbiter (even making that redundant eventually required the CPUs to decide what to do if they disagree so may as well handle it internally).

if the issue is radiation bit flipping, you could make that part overly shielded?

And bad pilot training, if I recall correctly.

Crashes caused by pilots failing to execute proper stall recovery procedures are surprisingly common, and similar accidents have happened before in aircraft with traditional control schemes, so I’m skeptical that there are any hardware changes that would have made much difference. The official report doesn’t identify the hardware or software as significant factors.

The moment to avoid the accident was probably the very first moment when Bonin entered a steep climb when the plane was already at 35,000 feet, only 2000 feet below the maximum altitude for its configuration. This was already a sufficiently insane thing to do that the other less senior pilot should have taken control, had CRM been functioning effectively. What actually happened is that both of the pilots in the cockpit at the start of the incident failed to identify that the plane was stalled despite the fact that (i) several stall warnings had sounded and (ii) the plane had climbed above its maximum altitude (where it would inevitably either stall or overspeed) and was now descending. It’s never very satisfying to blame pilots, but this was a monumental fuck up.

If the pilots genuinely disagree about control inputs there is not much that hardware or software can do to help. Even on aircraft with traditional mechanically linked control columns like the 737, the linkage will break if enough pressure is applied in opposite directions by each pilot (a protection against jamming).

I'm reminded of the Apollo moon landing where the computer was rapidly rebooting and being in an OK-ish state to continue to be useful almost immediately

[dead]

There's a huge difference between "manufacturer recommended updates, but airline waited until the last week to apply them" and "manufacturer didn't even acknowledge the issue" in terms of who the chorus is going to blame.

FWIW the "industry sources say" line on the incident is that it occurred on 30 October[1], so further back than ten days ago but of course there may have been other CME incidents at that time.

The European Agency Aviation Safety Agency [2] instruction describes the characteristics of the incident but not the date.

[1] https://www.theguardian.com/business/2025/nov/28/airbus-issu...

[2] https://ad.easa.europa.eu/ad/2025-0268-E

Gamma rays penetrate everything and have definitely been known to disrupt computer circuits.

> The grounding of Airbus A320neo aircraft around the world can be traced back to an incident on a JetBlue flight operating a Cancun to New Jersey service on 30 October.

> At least 15 passengers were injured and taken to the hospital after a sudden drop in altitude on the flight from Mexico was forced to make an emergency landing in Florida, US aviation officials said at the time.

> The Thursday flight from Cancun was headed to Newark, New Jersey, when the altitude dropped, leading to the diversion to Tampa International Airport, the US Federal Aviation Administration said in a statement.

> Pilots reported “a flight control issue” and described injuries including a possible “laceration in the head,” according to air traffic audio recorded by LiveATC.net.

> Medical personnel met the passengers and crew on the ground at the airport. Between 15 and 20 people were taken to hospitals with non-life-threatening injuries, said Vivian Shedd, a spokesperson for Tampa Fire Rescue.

> Pablo Rojas, a Miami-based attorney who specialises in aviation law, said a “flight control issue” indicated that the aircraft wasn't responding to the pilots.

https://www.stuff.co.nz/travel/360903363/what-happened-fligh...