NEMP protection - ACJ and BBJ Considerations

[mach 4.0]

Dani

Agreed, the title encouraged alot of time wasters and nonsense, more suited to jetblast.

However I cannot get away from the fact that the question is type specific to ACJ.

You say that all FBW a/c will have the same problem, but you have not supported this statement with any fact or reasoning. It is just another opinion.

It is possible that not all FBW a/c will react the same way, it depends very much on each particular system. Wouldn't you agree?

There is no shortage of opinions, but the only factual post I remember is from airbus instructor.

It should now be quite clear, this post is a search for knowledge. Despite some of the posters claiming they "know what they are talking about" due to number of hours, etc, etc we really have no further info on this subject.

Despite the questions irrelevance to mostly everyone, it could be a good learning experience. However the answer is beyond the knowledge of the average line pilot, and I suspect this is why no progress has been made.

[Human Factor]

I think it's probably reasonable to assume that if you're flying an airliner close enough to a rapidly emptying sunshine bucket to be effected by it, the least of your worries is going to be EMP.

[g0kmt]

Simple answer is down to cost vs risk!

Risk is low, cost to harden a320 against DEW/EMP is astronomical - so it never happens!!!! hardening that is!

Also be aware that certain specifics may be in breach of some national security agency rules! If you knew how hard a product was, you would also know how big to build your bomb to destroy it!

Microprocessor manufacturers could harden their products but the cost is prohibitavley high. Indeed as microprossor technology advances the physical distance between devices on a cpu/chip decreases the hardness also decreases such that true hardness becomes dificult to achieve!

No civilian design requirement exists so why allow design creep for a whim?

Data security is MUCH more an issue than nuclear hardening!

In terms of bandwith this thread is a waste of space, there are cheaper ways of achieving the demise of any aircraft regardless of type!

[mach 4.0]

Rainbow

Of course there is an answer. What in particular, do you find impossible to answer? Just because you do not know the answer does not mean an answer does not exist.

Take the battery for instance, will this be affected by NEMP?DEW? Is there an answer to that? yes! Airbus have confirmed, it will be unaffected. Will a switch work? yes, thererfore will a current flow to the solenoid, etc, etc

Human factor, suggest you read the thread, we have heard that one many times before, but that is not the question.

Gokmt

Thank you, but hardening is not the issue here whatsoever.

It is simply a comparisson between NEMP/DEW on an ACJ and BBJ. Thats it!

[Final 3 Greens]

Mach 4.0

Just one final thought.

Your logic is that you can step through your systems, bit by bit and arrive at a works/doesn't work conclusion for the whole. I believe that this is a rather naive view and it suggests a lack of exposure to testing complex systems, I'm not being insulting here, just commenting on what I see in the interests of trying to give you a different view to consider.

My experience in working with complex, interdependent, electronic based systems is that the only real proof (or should I say non proof of failure) is to test the whole system, since individual modules may pass a test, but when integrated, the system has a reasonable probability of failure due to unforeseen circumstances, what one may call a known/unknown scenario.

So we started with a deductive approach and then often fell back to an inductive approach to understand why the system did not work as we expected it to work. The causes of failure were often relatively trivial, but nonetheless the system, as a whole, failed.

And that was in conventional testing, not something as exotic as NEMP/DEW, where a system that is certified to operate with one set of parameters is then exposed to a different set of parameters.

That does not give you any hard data or logic, you may say and that is precisely the point.

One needs to test the system to have any degree of confidence in a hypothesis.

If I were a consultant to your boss, I would feel ethically obliged (after all it is his neck potentially on the block) to point out the severe limitations of this deductive methodology and also to point out that a full systems test is not feasible, so the confidence level in the hypothesis is adjusted accordingly.

[Sheep Guts]

I agree with 3 Greens. Larger systems are inherently because of their size more prone to total failures than smaller ones.NEMP damage is such a large an unforcasting type of scenario, that even most of the equipement said to be NEMP proof ( and sold to NATO standards and higher) really are only tested to certain parameters.

For example say the EMP pulse of energy came from an explosion behind the aircraft as opposed to the front. The natural shield of the Aircraft fuselage and its cargo and equipment would surely make it more NEMP proof than an occurence happening infront of the aircraft where there is little shielding at all.
NEMP is really a big broad happening that cant really be 100% protected as is there isnt such thing a 100% cleared mine field ( I once tried to impart on a colleague during a Hash walk in Kabul last year). So in thas instance, It would be hard on even a conventional non FBW aircraft such as 738 which would overtly suffer similair damage with similiar catastrophic outcomes.

[Rainboe]

It's becvause they haven't thought out the problem, just looking at it from a physical POV of 'what if some nutter exploded a nuke above the atmosphere.....?' they are trying to work out the problem (which can't be worked out), quite forgetting: why do it? how to do it (delivery etc)? what will be left on the ground after they have done it (because it will not be an act in isolation or without retaliation)? To give the problem some credibility, it was implied at the beginning 'it will almost certainly happen' (it won't).

So keep flogging that dead horse guys, there is no answer, but it's immensely amusing watching you try and get there. Work your slide rules frantically and leave the living to everyone else!

[tallsandwich]

Rainboe,

The moderator has ruled against you - the question is valid, and he has asked that all comments are constructive. If you still disagree, please direct your complaints to the moderator, not mach 4.0.

Unfortunately you still are talking about not being able to get a valid answer, yet we have clearly indicated that a satisfactory outcome of this thread could be:
1. A fun exercise just to learn and exchange information.
2. An answer to the question, albeit one with a low confidence factor or substantial assumptions attached to it.

I'm glad to know however you are still enjoying the debate.


g0kmt:

"In terms of bandwith this thread is a waste of space". Again the moderator does not agree - why don't you send him a message instead of wasting space on your comments? According to forum rules, your comments are the ones that will be deleted.


Thanks.

Let us be clear on several points ..

(a) I have no view as to the value of the thread topic. However, so long as the site's rules are met (and the posts are reasonably polite) the thread can work its way to whatever conclusion may evolve.

(b) I have not ruled for or against any poster (save to delete and edit posts which are not appropriate for a thread in this forum).

(c) in this forum, the role of the moderator essentially is one of facilitator .. not that of purveyor of personal prejudice.

.. but it is interesting to watch how a technically difficult topic develops ..

[rubik101]

Gamma gotcha

If this badly designed Airbus is flying close enough to the explosion to have all it's electronics wiped out, then the dose of gamma radiation will mean that the occupants have days, or if they are really unlucky, perhaps weeks to live.
So just what is the point of this discussion? If I fly the rest of my life in an NBC suit, I will not even begin to feel happier than I do now when I strap my Airbus to my backside and go to do battle with the elements.
Valid or not, my opinion is that the question is a bogus waste of everyone's time and a cheap dig at Airbus, once again. Massive design flaw!!! Phhhaahhh

[mach 4.0]

tallsandwich

appreciate your comments

Final 3 greens,

Agreed, however some reasoning/technical knowledge is surely better than for instance "chances are RAT will deploy"

Ruibik 101

Please dont waste our/ your time. we've heard that all before. If you read the thread, you will already see that I have accepted that thread title is poor and has encouraged alot of ridicule and nonsense.

I'll take this comment to be a request for the title to be varied a tad ...

I-Ford

Interesting, however I wouldn't say it is purely speculative to give a likely outcome to a BBJ in worst case NEMP/DEW damage. Maybe it is on an ACJ and that is the question I am interested in. Speculation is fine provided it is based on some technical reasoning and not just an opinion without any basis.

Just a reminder, this is not a debate on whether a nuclear detonation is likely or whether it is surviveable, or any other reason. It is purely to to discover the result of worst case NEMP/DEW on flight controls of ACJ and whether it is likely to be controllable.

If the nuclear explosion NEMP bothers you, forget about that and lets just consider DEW.

[Final 3 Greens]

Agreed, however some reasoning/technical knowledge is surely better than for instance "chances are RAT will deploy"

Only if systemic confidence levels are high, otherwise what's the difference?

Still, its an interesting discussion.

[Clandestino]

How the (N)EMP works, from wikipedia:

The electromagnetic radiation from an explosion (especially nuclear explosions) or an intensely fluctuating magnetic field caused by Compton-recoil electrons and photoelectrons from photons scattered in the materials of the electronic or explosive device or in a surrounding medium. The resulting electric and magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges

Now how the DEWs work, also from Wikipedia.

The primary damage mechanism is mechanical shear, caused by reaction (like a rocket) when the surface of the target is explosively evaporated.

So when we're talking about damage from (N)EMPs and DEWs are we comparing like and like? Seems not. If your airplane is hit by DEW (even in some avionics bus or part of fly-by-wire) there will be no induced voltage that can send damaging currents all through the systems, so no need to worry about your FBW getting knocked out by the single DEW hit.

But explosive evaporation of your aircraft's surface (or even worse underlying structure too) is another matter.

[Rainboe]

So any answers yet? We're still awaiting some slide rules to be put down and a solution to an unanswerable series of questions! Shame that so much criticism was directed at those that said no answers were possible, but Mach4- are you clearer now?