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| IL-2 Sturmovik The famous combat flight simulator. |
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#1
10-05-2010, 07:50 PM
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USAF feels Oleg's pain
Shot Down By The Hidden Flaw
http://www.strategypage.com/htmw/hte.../20101004.aspx October 4, 2010: The U.S. Air Force is facing growing problems with software reliability for aircraft. This is largely the result of so much more software being used to operate these airplanes. For example, flight testing of the F-35 was halted on October 1st, so that the software could be fixed. It was believed that a software error was causing fuel pumps to malfunction. The F-35 source code comprises about 8 million lines of code (a file about two gigabytes in size, that could easily fit on a thumb drive). Most modern PC operating systems have source code ten or more times as large, but PC bugs don't cause a $100 million aircraft to crash. Creating flawless software is very difficult, and expensive. It gets more complicated as the amount of software involved increases. This is an aircraft vulnerability that gets little media attention, yet it is very much present, and a growing threat at that. Then there's the security risks. The contractors who created the F-35 software, did not let the source code anywhere near the Internet, to ensure that Chinese hackers did not grab it. But this software is only valuable if it works. In terms of software, the F-35 is more advanced than the F-22, and has three times as much source code, and even more chances of something going wrong. Source code is the plain text version of the code that is written by programmers, and then turned into the 0s and 1s by a compiler program so that it can operate inside the dozens of microprocessors inside the aircraft. Software used in combat aircraft has grown enormously over the last two decades. The F-15 appeared in the late 1970s, and had electronics using only a few thousand lines of code. By 1995, upgrades and new equipment had increased this to over 100,000 lines of code. Ten years later the U.S. Air Force began replacing the CPUs (Central Processing Units, the "brains" of a computer) in their F-15E fighter-bombers. The ones being replaced were vintage 1988. Since then, CPUs had become fifty (50) times faster. Since 1995, the CPUs had become even faster. Naturally, the new CPUs make everything work faster on the F-15E, and allows the aircraft's electronics to do many things it could not do with its original equipment. It's a common problem with warplane electronics, for upgrades to come slowly. It's just not a matter of plugging in a new CPU. Many other new chips are required, and the software has to be rewritten to take advantage of the new capabilities. This takes time, and a lot of money and testing. The air force is reluctant to invest in these upgrades, because money is always tight, and buying new aircraft, or training, often are seen as better investments. The way around this is to build more recent aircraft so that they can be more easily, and cheaply, upgraded with more powerful electronic components. But in the end, if you want better performance these days, you need more software that will take advantage of the new hardware, but it's easier to create reliable hardware, than it is for software. The older F-15C has also received upgraded electronics, and new software to run it. The add-on equipment, like targeting pods, can easily double the amount of software needed to make the aircraft an effective weapon. But minor flaws in that software can make the aircraft much less deadly, or keep it from even taking off. I'm guessing that SoW is comparable to the F-35 software in complexity. The sim world is converging with real life aviation. 
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#2
10-05-2010, 08:47 PM
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For many years I had the idea that aircraft development time increased primarily by the growing need for stable software. Seems I was right.
You see it everywhere in western industry if vehicles are concerned. Can you believe carmakers wish to delete the physical connections between steer-wheels and pedal-brakes? I'm no luddite, but this goes too far. In a car you don't have the time to switch on a backup like in a plane. Those enormous amounts of hardware & software aren't exactly in the spirit of Kelly Johnson. Instead of having a few aircraft that are the most complicated and expensive but clearly superior, why not a whole bunch of cheaper and simpler craft to maintain numerical superiority? Not a single of those jets can fly in space yet the Space Shuttle's software is incredibly tiny in comparison. Instead of all those fancy computerized gizmo's why not develop a plane that can fly to twice the altitude of your competition so you can again dictate any rules of engagement? Think the X15 had a computer on board? I like computers, that's not it. But I rebuilt my own 25 year old car and thank myself, I can repair it all by myself. The only computers that thing has operate the digital dash and the radio.
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#3
10-05-2010, 09:10 PM
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I recently read something in a Brazilian car magazine about software problems in the Ford Fusion V6 who was leading to the automatic gearbox disengaging suddenly going to neutral.
No big deal, unless you are in the middle of overtaking a car on the road. Nothing mechanically wrong, just software problem,easily solved with reprogramming,but it´s scary that this sort of thing can happens in a perfect normal car with no warning...
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#4
10-05-2010, 10:21 PM
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Lockheed martin this time huh, surprised it was not Northrop Grumman again. I notice they were in the news again a few weeks back for ripping off the DoD yet again:
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#5
10-05-2010, 11:02 PM
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Other day I saw that computer viruses could infect car CPUs.I wonder if one can´t get its way trought a F-22 CPU?
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#6
10-05-2010, 11:41 PM
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Here's how I see it: the cockpit of a new jet fighter or Airbus is actually a flight simulator, with a real airplane attached to it. So, any problem you might have with your PC could also happen to the CPU on the aircraft. Not very conforting to think about!
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#7
10-05-2010, 11:45 PM
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There are methods for reducing the harmfulness of software errors in safety-critical systems. One is to get code written by three different teams, and use 'majority voting' if there is a conflict when the system is operating. The flaw with this is it assumes that different programming teams won't make the same sort of errors - a doubtful assumption to rely on.
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#8
10-06-2010, 06:54 AM
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From Mariner 1 via Ariane 5 to the SAAB Gripen prototype, the history of software in aviation is dismal. If a civil engineer built a bridge that collapsed, he'd be ruined. A software engineer builds his bridge again and again - hundreds of times - and when it finally stands up on its own there's a big party.
Thankfully physical modelling like Il-2/SoW has a better record than most, but many large software projects exhibit not just a lack of competence but a lack of understanding of the most basic precepts of engineering. It's not just that many big IT projects end up non-functional, they start out with designs that couldn't function in the first place. Computer Science grads need to be taught the difference between provable and non-provable designs and how to test ideas. dduff
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#9
10-06-2010, 07:04 AM
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The software industry is more akin to book or music publishing then any of the more traditional "professions" .
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#10
10-06-2010, 07:32 AM
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 Regulations are an interesting topic, I think what prevents a lot of mistakes within engineering are the numbers of people that check the designs, which is often the exact opposite with programming. I don't see a reason to impose regulations on non-safety critical programmers though.
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