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Airbus A320 – intense solar radiation may corrupt data critical for flight

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Re: Airbus A320 – intense solar radiation may corrupt data critical for flight

#161

Post by Nextgrid »

Loudergood wrote: post #157
jpollock wrote: post #148

Earlier quoted context omitted.

For example.... "Preliminary A330/A340 FCPC algorithm" "The algorithm did not effectively manage a specific situation where AOA 2 and AOA 3 on one side of the aircraft were temporarily incorrect and AOA 1 on the other side of the aircraft was correct, resulting in ADR 1 being rejected." So, you've got a system where _two_ of the three sensors are bad, and you need to deal with it.

I'm in awe of the fact that two sensors can be wrong AND agree with each other.

Those being analog sensors measuring analog, physical things, they will never exactly agree with each other; so there's a plausibility window. As long as the fault causes the sensors to remain within said window they will be considered as valid.

Re: Airbus A320 – intense solar radiation may corrupt data critical for flight

#162

Post by UltraSane »

Loudergood wrote: post #157
jpollock wrote: post #148

Earlier quoted context omitted.

For example.... "Preliminary A330/A340 FCPC algorithm" "The algorithm did not effectively manage a specific situation where AOA 2 and AOA 3 on one side of the aircraft were temporarily incorrect and AOA 1 on the other side of the aircraft was correct, resulting in ADR 1 being rejected." So, you've got a system where _two_ of the three sensors are bad, and you need to deal with it.

I'm in awe of the fact that two sensors can be wrong AND agree with each other.

It is just like having range of values considered to be equal for floating point numbers.

Re: Airbus A320 – intense solar radiation may corrupt data critical for flight

#163

Post by MaxfordAndSons »

sailfast wrote: post #36
MaxfordAndSons wrote: post #24

Earlier quoted context omitted.

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 stay buckled and I’m just a “normie” not afraid of flying that understands turbulence doesn’t always happen in a bell curve with some notice. Not sure if that makes you feel any better? :)

Having an understanding of the bell curve of turbulence makes you a bit more advanced than a normie on the aviation knowledge bell curve imo :)

Re: Airbus A320 – intense solar radiation may corrupt data critical for flight

#164

Post by hughw »

russdill wrote: post #159
hughw wrote: post #150

Earlier quoted context omitted.

Different band, sure. Same principle, right?

The difference between ionizing and non-ionizing radiation is quite different. But for much of the radiation effecting electronics at high altitudes it's largely subatomic particles. And of course you can block the type radiation that caused problems for the rpi with a good piece of paper.

Got it. Ty.

Re: Airbus A320 – intense solar radiation may corrupt data critical for flight

#165

Post by MaxfordAndSons »

rainsford wrote: post #124
MaxfordAndSons wrote: post #24

Earlier quoted context omitted.

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'm amazed how many grown ass adults on airplanes act like little kids when it comes to seat belts and basically everything else. Not just ignoring flight crew advice and common sense to generally stay buckled in order to gain maybe a minor amount of comfort and convenience being unbuckled, but unbuckling even when the seat belt sign is on and again common sense says being buckled in is the smart move. On my most rec…

lol yep. It's like they have the same mentality as being a schoolbus (which, it's similarly wild to me that kids are just implicitly allowed to not wear their seatbelts on them but I guess thats an even more intractable enforcement problem).

Also: people clapping the second the back wheels touch on landing is particularly hilarious to me because it implies an acknowledgement of the precariousness of flying, but a complete ignorance of the fact that you're just entering the second most dangerous 30 seconds of the entire flight.

Re: Airbus A320 – intense solar radiation may corrupt data critical for flight

#166

Post by tyingq »

op00to wrote: post #5

Solar radiation like solar wind, or sunlight? They don’t say.

Would guess "cosmic rays". Sun Microsystems had a batch of UltraSparc servers that were very sensitive to it, and it was a big issue.

https://docs.oracle.com/cd/E19095-01/sf4810.srvr/816-5053-10...

https://en.wikipedia.org/wiki/Cosmic_ray

Re: Airbus A320 – intense solar radiation may corrupt data critical for flight

#167

Post by sllabres »

rubatuga wrote: post #149
jpollock wrote: post #146

The design of the system is very interesting, particularly how it expects to handle errors. In 90's Telco, you used to have a pair of systems and if they disagreed, they would decide which side was bad and disable it. In modern cloud, you accept there are errors. There's another request in ~10+ms. You only look when the error rate becomes commercially important. My understanding of spacecraft is that there would be 3…

Space computers are generally in 3 with a hot spare

Space shuttle had five.

Four of them operating in a redundant set and the fifth performing non critical task, as descripted in [1]. The fifth is also programmed by a different contractor in a different programming language: #1-4 running the Primary Avionics Software System (PASS) programmed by IBM in HAL/S and #5 programmed by a different team of Rockwell International in assembly. [2]

[1] https://people.cs.rutgers.edu/~uli/cs673/papers/RedundancyMa...

[2] https://ntrs.nasa.gov/api/citations/20110014946/downloads/20...

Re: Airbus A320 – intense solar radiation may corrupt data critical for flight

#169

Post by K0balt »

Filligree wrote: post #126
K0balt wrote: post #102

Earlier quoted context omitted.

The idea was to build three completely different systems to produce the same data, so that an error or problem in one could not be reasonably replicated in the others. In a case such as this, even ideas about algorithms could result in undesirable similarities that could end up propagating an attack surface, a logic error, or a hardware weakness or vulnerability. The desired result is that the teas solve the problem…

And did they? Sometimes the solution is obvious, such that if you ask three engineers to solve it you’ll get three copies of the same solution, whereas that might not happen if they’re able to communicate. I’m sure they knew what they were doing, but I wonder how they avoided that scenario.

I think this would come down to team selection. At airbus they have the advantage of cultural diversity to lean on, I have no doubt that implementations would differ not only in implementation but in design philosophy, compromises, and priorities.

Re: Airbus A320 – intense solar radiation may corrupt data critical for flight

#170

Post by K0balt »

K0balt wrote: post #109
CrossVR wrote: post #45

Earlier quoted context omitted.

It wasn't rebooting, it ran out of memory and started aborting lower priority tasks. It was a excellent example of robust programming in the face of unexpected usage scenarios.

Fail safe/fail soft I still design this into many of the things I work on, especially if I’m working close to the metal on controller systems. At some point it becomes ridiculous / impossible but I’m often thinking about how a system would handle memory corruption, bit flips, invalid sensor data, etc. These days, somebody should design a triple redundant microcontroller that runs quorum on the gpio at the hardware le…

Ok so, turns out there are a lot of MCUs like this, including a riscV triple core lockstep with ECC lol. No super cheap ones, but microchip makes the AVR-SD which leverages a pair of their AVR8 cores in lockstep with ECC flash and RAM. It’s ~$1, so I think I’ll pick that as my next toy project to play with. Turns out, Simpsons already did it.
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