Following the Airbus A320 emergency airworthiness action, everyone will be talking about the ELAC (Elevator Aileron Computer) manufactured by Thales, which caused a sudden pitch-down without pilot input on JetBlue 1230 back in October. So here’s everything you need to know about ELAC. The ELAC System in the Airbus A320: The Brains Behind Pitch and Roll Control https://x.com/Turbinetraveler/status/1994498724513345637
Airbus A320 – intense solar radiation may corrupt data critical for flight
81–90 of 184 posts
Re: Airbus A320 – intense solar radiation may corrupt data critical for flight
#82Earlier quoted context omitted.
I am worried about a software fix for what looks like hardware problem.
Gracefully handling hardware faults is a software problem. The Air France Flight 447 crash was the result of bad software and bad hardware.
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).
Re: Airbus A320 – intense solar radiation may corrupt data critical for flight
#83Earlier quoted context omitted.
> 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. I’m surprised passengers are allowed to unbuckle for so much of each flight. You can get injured while buckled it, but that seems less common.
The flight attendants/safety card will tell you to stay buckled whenever seated, even if the seat belt sign is off, but many (most?) people will ignore that guidance and stay unbuckled for as long as they are technically allowed. Only aviation professionals or recovering flight phobics like me who have watched every episode of Air Crash Investigation will take proactive safety measure of their own accord. To normies…
No reason to not buckle, I keep the belt a little looser, but buckled the entire time. Esp on Boeing planes, I want to get sucked out with the seat.
Re: Airbus A320 – intense solar radiation may corrupt data critical for flight
#84Earlier quoted context omitted.
Gracefully handling hardware faults is a software problem. The Air France Flight 447 crash was the result of bad software and bad hardware.
And bad pilot training, if I recall correctly.
I suppose because they were not instructed to work around the software and hardware flaws.
Re: Airbus A320 – intense solar radiation may corrupt data critical for flight
#85Re: Airbus A320 – intense solar radiation may corrupt data critical for flight
#86I wonder how the incident was diagnosed? Does the FDR record low level errors that might've contributed to this? I thought that it only recorded certain input parameters and high-level flight metrics but I'm no expert.
If a radiation event caused some bit-flip, how would you realize that's what triggered an error? Or maybe the FDR does record when certain things go wrong? I'm thinking like, voting errors of the main flight computers?
Anyway, would be very interested to know!
Re: Airbus A320 – intense solar radiation may corrupt data critical for flight
#87From newspaper reporting on this, they are rolling back a software update. I wonder what was the original cause or the update? How often are flight computers software updated and why?
Re: Airbus A320 – intense solar radiation may corrupt data critical for flight
#88Earlier quoted context omitted.
See my other comments in the other threads. This does not have EDAC. I was as surprised as you but it doesn't seems to be an MCU but a composition of several distinct chips. That flight computer was designed in the 90's and updated in 2002 with a new hw variant that does have edac. So yes, for this kind of thing, I can buy that a bit flip happened. You can see much more data in the report: https://www.atsb.gov.au/sit…
> This does not have EDAC. I was as surprised as you but it doesn't seems to be an MCU but a composition of several distinct chips. 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? Maybe ECC was seen as redundant in that model?
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.
Re: Airbus A320 – intense solar radiation may corrupt data critical for flight
#89Earlier quoted context omitted.
I think you're confusing a type certificate (certifying the airworthiness of the aircraft type) with a type rating , which certifies the pilot is qualified to operate that type. Significant internal hardware changes might indeed require re-certification, but it generally wouldn't mean that pilots need to re-qualify or get a new type rating.
No I meant designing a new aircraft with a new type certificate instead of creating the A320neo generation on the same type certificate. The parent comment wondered why Airbus would keep the old computers around, I tried to explain why they keep a lot of things the same and only incrementally add variants. Adding a variant allows them to be flown with the same type rating or with only differences training (that's wha…
Asking from ignorance: shouldn't the computer design be an implementation detail to the captain, while the interface used by who pilots stays the same for that type of airplane? I understand physical changes in the design need a retraining but the computer?