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A400M Airbus Flier crashed because of software issues

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Re: A400M Airbus Flier crashed because of software issues

#81

Post by shepardrtc »

castell wrote: post #42
alandarev wrote: post #18

Software contractor for Airbus and Rolls-royce here. All safety critical software (every piece of code ran on-board is safety critical the least) in aerospace needs to pass the DO-178 standard [1]. That is far more serious than standard unit tests you are used to in node.js applications. Generally speaking, to develop a piece of code under that standard it takes 20% of time to write the code, and 80% to testing, and…

Which programming language is commonly used there? Ada, C, C++, JOVIAL, Asm?

Nowadays, its C/C++. In the past it was Ada (at least in the US). Ada was created specifically for this sort of thing (and was actually a requirement for certain projects), but it never gained popularity so companies would just petition the government to use C/C++ instead. Its a shame, too. Ada is fantastic if you want to avoid bugs. I wish more people would give it a chance.

On the other hand, I also wonder why people don't think of using Erlang for something like this. The VM is designed for a ridiculous amount of uptime, it has a supervisor tree that can monitor and restart failed processes, and it can interface with C/C++. A rock-solid VM should be running and monitoring life-safety systems.

Re: A400M Airbus Flier crashed because of software issues

#82

Post by [deleted] »

castell wrote: post #42
alandarev wrote: post #18

Software contractor for Airbus and Rolls-royce here. All safety critical software (every piece of code ran on-board is safety critical the least) in aerospace needs to pass the DO-178 standard [1]. That is far more serious than standard unit tests you are used to in node.js applications. Generally speaking, to develop a piece of code under that standard it takes 20% of time to write the code, and 80% to testing, and…

Which programming language is commonly used there? Ada, C, C++, JOVIAL, Asm?

[deleted]

Re: A400M Airbus Flier crashed because of software issues

#83

Post by TheLoneWolfling »

tim333 wrote: post #38
lucaspiller wrote: post #8

Earlier quoted context omitted.

> So, not much information why the computers sent conflicting commands and also why the engines power down in such a situation. I think shutting down the engines is probably the safest option when this sort of thing happens. You could argue they should stay in the present setting, but what would happen if one engine were at 0% and another 100%? Most aircraft are pretty good at gliding even without power, and I'd assu…

>what would happen if one engine were at 0% and another 100% Planes are designed to fly fine in that situation - it's what you get if one engine breaks down. Now landing the thing with one engine stuck on 100% would be interesting. I guess you could kill the engine somehow - turn off the fuel or pull the fuses.

An engine stuck on has happened before, though I believe this was only flight idle:

https://en.wikipedia.org/wiki/Qantas_Flight_32

Mind you, that was the result of an uncontained engine failure.

Re: A400M Airbus Flier crashed because of software issues

#84

Post by [deleted] »

alandarev wrote: post #18

Software contractor for Airbus and Rolls-royce here. All safety critical software (every piece of code ran on-board is safety critical the least) in aerospace needs to pass the DO-178 standard [1]. That is far more serious than standard unit tests you are used to in node.js applications. Generally speaking, to develop a piece of code under that standard it takes 20% of time to write the code, and 80% to testing, and…

[deleted]

Re: A400M Airbus Flier crashed because of software issues

#85

Post by sfrank »

TeeWEE wrote: post #60
alandarev wrote: post #18

Software contractor for Airbus and Rolls-royce here. All safety critical software (every piece of code ran on-board is safety critical the least) in aerospace needs to pass the DO-178 standard [1]. That is far more serious than standard unit tests you are used to in node.js applications. Generally speaking, to develop a piece of code under that standard it takes 20% of time to write the code, and 80% to testing, and…

I'm quite baffled at the fact that this standard does not include formal verification of the software models used. Formal verification and state space analysis can prove that the software "model" will not fail. State space exploration of the actual implementation is actually often not feasible due to the enourmous amount of states. So my question: Are you doing formal analysis of the software models/designs? I know t…

The DO-178B/C explicitly does not specify how verification is done but describes the properties that are expected of the verification evidences that you submit to the certification authorities; so formal verification is perfectly fine as one item on your verification check list. In particular DO-333 amends DO-178C with specific topics concerning formal methods.

For example Astree [1] has been developed for decades now, with Airbus as one of the major sponsors.

[1] http://www.astree.ens.fr/

Re: A400M Airbus Flier crashed because of software issues

#86

Post by tormeh »

shepardrtc wrote: post #81
castell wrote: post #42

Earlier quoted context omitted.

Which programming language is commonly used there? Ada, C, C++, JOVIAL, Asm?

Nowadays, its C/C++. In the past it was Ada (at least in the US). Ada was created specifically for this sort of thing (and was actually a requirement for certain projects), but it never gained popularity so companies would just petition the government to use C/C++ instead. Its a shame, too. Ada is fantastic if you want to avoid bugs. I wish more people would give it a chance. On the other hand, I also wonder why peop…

Using C/C++ on these projects is idiotic. If Airbus used C/C++ then they deserve all the financial loss in the world. They have blood on their hands.

Re: A400M Airbus Flier crashed because of software issues

#87

Post by sliverstorm »

calebm wrote: post #74
alandarev wrote: post #18

Software contractor for Airbus and Rolls-royce here. All safety critical software (every piece of code ran on-board is safety critical the least) in aerospace needs to pass the DO-178 standard [1]. That is far more serious than standard unit tests you are used to in node.js applications. Generally speaking, to develop a piece of code under that standard it takes 20% of time to write the code, and 80% to testing, and…

I wrote (non-critical) software for the A400M. I don't think that standards like DO-178B necessarily lead to higher quality code; my experience was that 80-90% of time was spent doing documentation, testing, and in general, trying to prove that the software was going to work right, leaving the engineers with very little time to write the actual software...

in general, trying to prove that the software was going to work right, leaving the engineers with very little time to write the actual software...

Sure sounds like the way it should be to me. Maybe it needs to be made easier to prove your software is correct, but to me it seems like for systems like airplanes, code that cannot be proven correct is worthless.

Considering most programmers are said to produce 6 lines of good code a day, maybe it's not even actually slower in the end if the formal verification process filters out every other line you would have written that day.

Re: A400M Airbus Flier crashed because of software issues

#88

Post by Jtsummers »

shepardrtc wrote: post #81
castell wrote: post #42

Earlier quoted context omitted.

Which programming language is commonly used there? Ada, C, C++, JOVIAL, Asm?

Nowadays, its C/C++. In the past it was Ada (at least in the US). Ada was created specifically for this sort of thing (and was actually a requirement for certain projects), but it never gained popularity so companies would just petition the government to use C/C++ instead. Its a shame, too. Ada is fantastic if you want to avoid bugs. I wish more people would give it a chance. On the other hand, I also wonder why peop…

Erlang's model is entirely appropriate, but the language and VM aren't. This code is often running on small embedded chips (so you'd need to port the VM) and the software has hard real-time requirements, which the Erlang VM is not (currently) set up to handle, nor would it necessarily be able to achieve on the commonly used processors. Another strike against the language (as much as I love it) is that it's dynamically typed. That's less appropriate for this sort of software. There are static analysis tools for Erlang that mitigate this, but it's still an issue. Large classes of bugs and errors can be eliminated or minimized with statically typed languages or with static analysis tools if they're well integrated into the build process. A real-time, statically typed language with Erlang's semantics and compiled to native binaries would be a boon, however.

I'll speak to the 787 avionics system. It used a system of channels/buffers and processes very much like what Erlang and Go use for interprocess communication (I'm trying to remember now if channels could be received in multiple processes like Go or if only a single process could receive like in Erlang). This was an excellent model for what we were doing, and really for a lot of systems this sort of CSP and actor style model maps well.

Re: A400M Airbus Flier crashed because of software issues

#89

Post by lambdaelite »

tormeh wrote: post #86
shepardrtc wrote: post #81

Earlier quoted context omitted.

Nowadays, its C/C++. In the past it was Ada (at least in the US). Ada was created specifically for this sort of thing (and was actually a requirement for certain projects), but it never gained popularity so companies would just petition the government to use C/C++ instead. Its a shame, too. Ada is fantastic if you want to avoid bugs. I wish more people would give it a chance. On the other hand, I also wonder why peop…

Using C/C++ on these projects is idiotic. If Airbus used C/C++ then they deserve all the financial loss in the world. They have blood on their hands.

Keep in mind they don't use C/C++. They use C/C++ with a coding standard (like MISRA), static analysis tools, validated compilers, development processes incorporating change control, documentation, verification and validation, etc.

What alternative are you suggesting?

Re: A400M Airbus Flier crashed because of software issues

#90

Post by leejoramo »

rurounijones wrote: post #5

Watching too many air-crash investigation episodes had lead me to believe 0% of media reported "facts" surrounding plane crashes. I will wait for the official accident investigation report.

As a kid in the 1980's with a 747 captain for a father, I followed plane crashes with great interest. The difference between the main stream media and what was in Aviation Week's coverage was shocking. Even with the release of the official report, Main Stream media would continue to mis-report, where as Aviation Week would reprint the majority of the report.
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