Another big recall 44

[enginesrus]

https://www.cnn.com/2023/09/06/business/air-bag-recall/index.html

Will they ever learn a tin can with no pressure relief system, is just not the proper pressure vessel.

 

[Sparweb]

I think we are getting caught up in the numbers, a bit.

Um... wait a moment....
...Scrolling back up the the top of the page briefly to check...

... yeah I'm not mistaken; we are supposed to be engineers here. So I believe it's normally an engineer's job to apply numbers to technical problems in order to understand the solution.
OK enough of that..

</sarcasm>

Sorry Dik, it just struck me as funny, given the context.
I'm regularly expected to apply numerical analysis to probabilities and consequences of failure. In Aero we call it "1309" and these inflators are perfect example of a "thirteen-oh-niner" kind of problem.

In fact, my very point revolves around the scarcity of this failure mode, and the much, much worse consequences of all other kinds of failure involved in airbags in cars, plus all of the other ways that people can be killed in auto accidents. This NHTSA issue has little significance compared to the many other pervasive and terrible issues in their mandate. Focusing their attention on this diverts their attention away from bigger problems, and could in fact cause a backslide, if trust in auto safety mechanisms is undermined (more than it already is).

 

[dik]

Hehehehehe

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Alistair_Heaton]

Was thinking about our aircraft systems and the backups and if there is a comparison.

They now don't give us 2 fire bottles per engine, we are down to 2 cross linked. And they have taken the halon away.

I can't find any stats but I am pretty sure that there are more people killed changing split rim wheel tyres per month in the USA than have been total for these air bags.

And if you could get two states to change to requiring seat belts then the issue would disappear.

 

[Sparweb]

AH,
As I understand it, the igniters that set off the fire bottles are the same technology that initiates the airbags in cars (just in a different package).
No comment on after-market auto mods - proceed at your own risk.

 

[enginesrus]

So when a problem exists in private vehicles it should just be ignored because only a handful of people have lost their eye sight (or life) over the issue.
From that I suppose most don't value that special ability, and consider the gamble worth it.
When aircraft crash huge efforts go into trying to solve the cause, when the cause is found, the problem is fixed. I'm sure glad that, "the we don't see a problem here because only a very small percentage of people have had injury's, folks", are not involved in aircraft incidents. If they were the Max 8 would never have been fixed as well as other planes that had major problems. Sorry the logic is just wow, no words for it.

 

[dik]

Seatbelt States...

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1703900487/tips/SeatBeltLaws_March23_t3jszi.pdf[/url]

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[3DDave]

All US states, except New Hampshire, require seat belts. Most states have laws allowing police to stop and issue a ticket solely for failure to wear a seat belt. The remainder allow a ticket to be issued as an addition any time a car is stopped if the occupants fail to wear seat belts. There are some overlap cases concerning children - some states that won't pull over a driver for failure to wear a seat belt will pull over for an unbelted child.

I guess the issue won't disappear due to making a change that cannot be made.

Halon production ceased world-wide in 1994. Remaining stocks are reclaimed from old systems.

 

[dik]

That's simplified in Canada... Unless for medical reasons, everyone wears one in all places except the trunk.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Alistair_Heaton]

For what I read which I can't find the link to now.

After ignition the burn rate is much higher due to the speed of required deployment being increased and the pressure is higher due to the bag having to take the full load of deceleration. And there was something to do with the piping because the gas speed is way higher. And its a cubed equation which is in the mix.

There are major issues with most aircraft types which are never fixed. The fundamental issue with the MAX is still there they have just tweaked a system to allow the pilots to recover from it. All the other issues are still there. They are making them do significant changes to the MAX 10 which is why its delayed but the 8 still has them. And they won't be fixed.

 

[zeusfaber]

So when a problem exists in private vehicles it should just be ignored because only a handful of people have lost their eye sight (or life) over the issue.
From that I suppose most don't value that special ability, and consider the gamble worth it.

This speaks to one of my pet peeves.

Is the engineer's responsibility:

a. to take every reasonably practicable action to reduce risk?

or

b. to act to reduce risk so far as is reasonably practicable?

I'm disheartened by the number of engineers I encounter who struggle to understand the difference between these two approaches.

UK law (I'd be interested to hear what happens elsewhere) favours option (b) - but a plethora of cottage industries has grown up offering to address risks that are already vanishingly small, while preying on employers' fear of being prosecuted for not buying a bit of "safety" that they could have done.

A.

 

[dik]

zeus... I would suggest the second approach... 'every' may be a little difficult to achieve in the strictest sense.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[IRstuff]

every reasonably practicable action to reduce risk

Seems to me that the issue is some engineers also don't understand
> reasonably practicable
and
> risk

These are not hard engineering cliffs, and halving the risk potentially might be a factor of 10 less reasonably practicable.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[FacEngrPE]

Functional safety principles can be applied to anything. Application details will vary

Risk = The probability that a dangerous event will occur × The extent of damages (costs) from a dangerous event.
The acceptable residual risk depends on various factors:
[ul]
[li]Country/Region[/li]
[li]Society[/li]
[li]Laws[/li]
[li]Costs[/li]
[/ul]
The acceptable residual risk has to be estimated on a case-by-case basis. It has to be acceptable to society.

In the US OSHA has issued a large number of prescriptive rules which have the status of "recognizing hazards" under the general duty clause. Be aware there are edge cases where specific prescriptive rules will not promote safety. Engineers need to understand their designs (not do a concept, then toss the concept to a designer to finished unsupervised).

5.Duties
(a)Each employer --
(1)shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees;
(2)shall comply with occupational safety and health standards promulgated under this Act.
(b)Each employee shall comply with occupational safety and health standards and all rules, regulations, and orders issued pursuant to this Act which are applicable to his own actions and conduct.

 

[dik]

Fac... good publication...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[SwinnyGG]

But most importantly the actuation device could be made fool proof so as not to cause an injury

This statement right here speaks to the core of your attitude about engineered devices, and why you so frequently wind up in arguments on this forum where no one is on your side.

Read this slowly until it soaks in:

Ensuring 100% safety or 100% reliability under all possible circumstances for all engineered devices is a literal impossibility. It is not possible. Period. That's not an opinion, it is a literal fact. It's as incontrovertible as gravity or the passage of time. The amount of money you want to spend and the amount of engineering time you have available to dedicate to design, testing, or both are immaterial. You will never achieve 100% safety, ever.

The engineers in this thread understand that fully. It's a law of reality we operate within every single day of our professional lives.

So how do we respond? How do we design things that go to market containing some non-zero percentage of risk and still sleep at night? We, very simply, do our best to evaluate potential risks, and we do our best to eliminate them where we can.

So when a problem exists in private vehicles it should just be ignored because only a handful of people have lost their eye sight (or life) over the issue.

It isn't being ignored. NHTSA has issued a recall and we've been discussing it for months. That's not ignored.

From that I suppose most don't value that special ability, and consider the gamble worth it.

I bet you're still driving your car around, and it's probably got airbags in it. So.... by action you're demonstrating that you also 'consider the gamble worth it', whatever that means.

When aircraft crash huge efforts go into trying to solve the cause, when the cause is found, the problem is fixed.

It is 'fixed' - inverted commas here because I am quite sure your definition of 'fixed' does not well align with the lowest-cost, shortest-time, workaround style changes often implemented to resolve design problems in the aerospace world - when it can be fixed. Which it can't always be. Do some research into the Max 8 trim system 'fixes' and what was actually done.

I'm sure glad that, "the we don't see a problem here because only a very small percentage of people have had injury's, folks", are not involved in aircraft incidents. If they were the Max 8 would never have been fixed as well as other planes that had major problems. Sorry the logic is just wow, no words for it.

This made me chuckle. Several of the people responding to this thread and trying to explain various things to you are literal, actual Aerospace Engineers© who design things that you fly around in. Notice how we all have a similar point of view? That's because they understand the reality of mass producing hundreds of millions of a particular thing, and that that's fundamentally different from manufacturing a few hundred of another, different thing, and that those worlds don't overlap nearly as much as the general public thinks they do.

No matter how hard we try you just don't seem to understand. Or have any desire to understand.

As previously discussed in this thread, the available data covers roughy 14 years. In that time, Americans have driven roughly 40 trillion miles. 40 trillion.

Total known fatalities: 7. So that's 1 every 5.8 trillion road miles driven, roughly. If you drive the same number of miles as the average American, your annual risk of being a victim of an injury due to an exploded airbag inflator is roughly 0.0000000022%. 1 in 450,000,000..

If your goal is to take that risk down to zero, what is worth to you? Is it worth every airbag costing $25,000 because airbag development costs go up by a factor of 100, so now every car has a base MSRP of $200,000 to cover all 8 airbags they all come with these days? Is it worth not being able to keep a car any longer than 3 years, to eliminate the roughly 1 in 2 billion change of an airbag inflator being compromised by long term moisture exposure?

 

[enginesrus]

SwinnyGG,

All that needs to happen is build the inflator out of thicker stronger alloy, and have an over pressure exhaust to exit the gases away from the driver or passenger, during an over pressure condition. And go back to a stable propellant.
Its called doing something to improve a bad design. No attitude problem here, its called getting attention to problems that exist. You know the topic here, "Engineering Failures", AKA bad designs.

 

[SwinnyGG]

All that needs to happen is build the inflator out of thicker stronger alloy, and have an over pressure exhaust to exit the gases away from the driver or passenger, during an over pressure condition. And go back to a stable propellant.

Right, you know it all as usual.

File your patent and I'm sure they'll be breaking your door down to get at you to make a deal.

Good luck.

No attitude problem here

Incorrect.

Here's the attitude problem.

The existing airbag inflator technology that you have problems with operates with a system COR something like 0.999999999987. That number means nothing to you, because you've never designed anything, let alone a complex life safety system like an airbag system - and as a result you have absolutely no clue what an insane level of performance this is, and how difficult it is to achieve performance levels like that.

Not only have you never designed a complex life safety system, you've also never designed anything for mass production, let alone a component that is going to be produced literally in the tens of millions, which way beyond the scale of what most people consider 'mass production' - it's literally another level. You are completely ignorant of the challenges involved with manufacturing safety components on that scale, and the level of engineering required to achieve the consistency required for the hard parts to perform at the level they do.

Yet you think that with no experience whatsoever, from your couch, you have a better idea and that it's all so very simple. Despite many highly trained and experienced engineers telling you otherwise and attempting to explain why, in your world we're all idiots that don't care.

You may be insulted by how direct I am in responding to you frequent nonsense posts. Ok. I (and though I can't speak for them, I'm sure I am not alone) am insulted by your continued insinuation, in basically every thread you start about some engineering problem you think exists, that none of us know what we're doing and that you know better because you've thought about it more, or whatever. It's very clear that you're here because you want to get some sort of validation from an engineering community that you're smart, and you're one of us, and all your ideas are so great, in the hopes that we'll all sit in a circle with our legs crossed while you educate us. That is never going to happen. You could move an inch closer to that if you showed up here with a genuine desire to learn, and you listened to comments in your threads; you do neither, ever.

It is possible for a layman to come up with a bigger better idea or some earth-shattering innovation from their couch; it does happen every once in a blue moon. After many months/years of reading your threads across many subforums, I can state with high confidence that you are not one of those people. You are very nearly completely ignorant on every topic in which I've ever seen you post on this forum. When you're presented with counterargument, you ignore it and throw up your hands and eventually just complain about how we're all ignoring your contrived 'facts' or how none of us care about anything you say.

We don't care about the things you say because your ideas are bad. The ratio between your confidence and ignorance is absolutely staggering. You have absolutely no clue what you're talking about. Your understanding of issues like this one is completely wrong.

I'm so tired of defending the craft of engineering from you. I really wish you'd just give it up and go post in some other forum where people agreed with you - I'm sure you could find one. If I was in charge of this forum, you'd have no choice.

 

[IRstuff]

All that needs to happen is build the inflator out of thicker stronger alloy,

>> Congratulations, you've just designed a pipe bomb

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[zeusfaber]

and have an over pressure exhaust.....

This is where it gets interesting because, unless the pressure relief device is extraordinarily reliable, fitting it is likely to do more harm than good - the occasional premature activation preventing correct deployment of the airbag being a greater risk than the extremely remote burst that you're trying to prevent (grossly different accident probabilities, with broadly similar consequences).

Once we've identified a potential "safety measure" human beings seem to have an innate blind spot to any associated unintended consequences. It's difficult, but important, to ask searching questions around everything that's being proposed in the name of safety.

A.

 

[XR250]

The ratio between your confidence and ignorance is absolutely staggering

That made me laugh. Will have to add that to my list of insults.