61–70 of 184 posts
Do they really need to ground the entire fleet for that? One incident for ten thousand planes in the air for years. I'd think that giving airlines two months to fix it would be sufficient.
I imagine it could help with Airbus marketing. "We take proactive measures, whereas our competitor only takes action after multiple fatal crashes!"
Earlier 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…
The recalled aircraft include the latest A320neo model, some of which are basically brand new. Why would they be using flight computers from before 2002? Why is an old report from 2008, relating to a completely different aircraft type (A330), relevant to the A320 issue today?
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.
Earlier 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…
The recalled aircraft include the latest A320neo model, some of which are basically brand new. Why would they be using flight computers from before 2002? Why is an old report from 2008, relating to a completely different aircraft type (A330), relevant to the A320 issue today?
Earlier quoted context omitted.
The recalled aircraft include the latest A320neo model, some of which are basically brand new. Why would they be using flight computers from before 2002? Why is an old report from 2008, relating to a completely different aircraft type (A330), relevant to the A320 issue today?
The neo is not brand new - it's an incremental update to the 320. neo refers to New Engine Option
They didn't say the design was brand new.
Do they really need to ground the entire fleet for that? One incident for ten thousand planes in the air for years. I'd think that giving airlines two months to fix it would be sufficient.
Earlier quoted context omitted.
In redundant systems like these, how do you avoid the voting circuit becoming a single point of failure? Eg. I could understand if each subsystem had its own actuators and they were designed so any 3 could aerodynamically override the other 2, but I don't think that's how it works in practice.
if the issue is radiation bit flipping, you could make that part overly shielded?
Earlier 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…
I’d really, really like to know what microcontroller family this was found on. Assuming that this is a safety processor (lockstep, ECC, etc) it suggests that ECC was insufficient for the level of bit flips they’re seeing — and if the concern is data corruption, not unintended restart, it means it’s enough flips in one word to be undetectable. The environment they’re operating in isn’t that different from everyone els…
proper SEU mitigation goes far beyond ECC. Satellites fly higher than the A320, and they (at least the ones I know about) use Triple Modular Redundancy: https://en.wikipedia.org/wiki/Triple_modular_redundancy https://en.wikipedia.org/wiki/Single-event_upset For manned spaceflight, NASA ups N from 3 to 5. Other mitigations include completely disabling all CPU caches (with a big performance hit), and continuously refre…
Earlier 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…
The recalled aircraft include the latest A320neo model, some of which are basically brand new. Why would they be using flight computers from before 2002? Why is an old report from 2008, relating to a completely different aircraft type (A330), relevant to the A320 issue today?
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.