modern aircraft and their relience on computers

i was watching this wings program on 556 on sky
they were showing the most advanced aircraft and so forth
and how they heavily relly on computers to give the piolet more room to do his things.

for example on the harrier the pilot controled how the aircraft hoverd and so
and with the new f-35 its all done by computers so the pilot just has to point it in the direction.

so making aircraft most relient on computers be a weekness in its self
since if they were taken out with a emp or something the whole aircraft would be useless

[edit on 2-1-2006 by bodrul]

so making aircraft most relient on computers be a weekness in its self

I agree. The F-117 comes to mind. Take out the computers on this baby and you're SCREWED, because the F-117 wouldn't be able to fly without them. It would drop like a rock. A lot of people don't like total computer control because it takes the humans out of flying, and that's no fun.

Yeah, but it makes certain stealthy designs able to fly all together, and most militayr equipment is heavily shielded against emp's.

Well how many F-117 have dropped like a rock since they were introduced into service?

You cant continue to make more capable and sophisticated machinery without more reliance on computers and technology, the two go hand in hand. When EMP weapons become easily available we’ll deal with them, right now were relatively safe form EMP.

Truttseeker is correct, all of the electronic avionics are sheilded against cosmic rays and emf's You gota think too, if we ever had to deliver a nuke we want our crafts getting back right? It would have to be a little more complicated than a emp taking out our aircraft.

Also a lot of these aircraft have multiple fault tolerant redundant systems to prevent total system failure incase of a major outage. Some of them even have backup hydraulic systems so if the electronics go the pilot has at least that. Though you are right for the most part in the sense that most new aircraft are "inherently unstable" and cant fly without the computer making constant adjustments.

You gotta remember that a lot of modern aircraft simply could not be controlled effectively if at all without the use of computers. They must be unstable in order to maneouvre well and human reactions simply are good enogh to make the small adjustments required. Whilst the avionic systems are still vulnerable in the event of an exo atmospheric nuclear explosion the likelyhood and risk is acceptable. How many harriers have crashed in transition? I think the figures would show a need for computers!

Something else to think about is that the software that is run on these avionic computer systems, and especially the software that runs on the embedded systems controlling actuators and reading from sensors, is formally verified before production.

See Wikipedia : Formal Verification and Formal Methods

Essentially in a nutshell they take a specification and model it, then formally verify that it is correct.

The software that runs on these systems is not as crappy as the software that we have become accustomed to as consumers.


[edit on 2006/1/3 by McGrude]

Well how many F-117 have dropped like a rock since they were introduced into service?

If my memory serves me correctly, there was an F-117 that crashed a few years back over Virginia. The control systems failed, and the tail just fell off. I'll see if I can find a link to the story.

I do agree with you, though. As aircraft and their systems become more sophisticated, planes are obviously going to have to rely on computers more and more.

Originally posted by BlackThorn311
I do agree with you, though. As aircraft and their systems become more sophisticated, planes are obviously going to have to rely on computers more and more.

Right - and to read between the lines they are relying on unreliable systems.

A major goal of modern computer science and computer hardware engineering is how to make reliable systems out of unreliable components.

This is most often acheived in such highly critical systems using a great deal of redundancy, since you can lose one unit and continue operating with two operational spares - but what if one of them is lying ( e.g. the component claims it is working but it is not ). So now you have a tripple redundant system with one known failed unit, one failed unit that claims to be working, and a working unit - which one is at fault from an analytical perspective (that is from the perspective of the montoring computer system that maintains the status of its subordinate systems)? The failed unit is a given, but your sensors readings from the two 'working' units are different, which do you trust? Is the control surface in the up position or the down position?

Some interesting reading from our friends at Wikipedia :

Byzantine failure

Byzantine refers to the Byzantine Generals' Problem, an agreement problem in which generals of the Byzantine Empire's army must decide unanimously whether or not to attack some enemy army. The problem is complicated by the geographic separation of the generals, who must communicate by sending messengers to each other, and by the presence of traitors amongst the generals. These traitors can act arbitrarily in order to achieve the following aims: trick some generals into attacking; force a decision that is not consistent with the generals' desires, e.g. forcing an attack when no general wished to attack; or so confusing some generals that they never make up their minds. If the traitors succeed in any of these goals, any resulting attack is doomed, as only a concerted effort can result in victory.

The Byzantine failure assumption models real-world environments in which computers and networks may behave in unexpected ways due to hardware failures, network congestion and disconnection, as well as malicious attacks. Byzantine failure-tolerant algorithms must cope with such failures and still satisfy the specifications of the problems they are designed to solve. Such algorithms are commonly characterized by their resilience t, the number of faulty processes with which an algorithm can cope.

My example of a faulty unit that is lying is a traitorous general in the following quote.

Byzantine Fault Tolerance

The problem is made difficult by the presence of traitorous generals who may not only cast a vote for a suboptimal strategy, they may do so selectively. For instance, if nine generals are voting, four of whom support attacking while four others are in favor of retreat, the ninth general may give a vote of retreat to a few generals and a vote of attack to the rest. Those who received a retreat vote from the ninth general will retreat, while the rest will attack (which may not go well for the attackers).