I think this is over-simplifying the situation. Yes, change the wiring for new builds to meet the regulations but It could well be that retrofitting the existing 800 or so 737's as mentioned in the article could increase the risk over-all.
But I would not trust Boeing to make that calculation and even the FAA's reputation has been dented (which is why I think they are being hard-arses about it) but it could be retrofitting is not the right choice.
I would probably be happier if the FAA and the ESA decided independently whether to allow it.
It's not just money; there is always risk in any hardware rework. If the rework is not done correctly and a plane crashes, even if on a test flight, then your "safety fix" has made the world a worse place.
In this particular case the fact that it is aviation standards for wire separation at issue, when those are typically stupefyingly conservative, means that "doing nothing" may well be the safest course. But I am NOT an expert in this area, so don't trust me!
One way to help make the decision is to try and get money out of the equation. If the two options are "pay for the rework" or "pay a fine equal to the cost of the rework", then any company that opts for the fine might actually believe in that approach.
I get your point, but isn't it ultimately about money anyway? If they can wire a plane correctly when they're building it, they surely can rewire a plane later - they might have to remove more stuff, worst case scenario reverting the plane to the same state it would be for an original rewire, and I suppose the reason they don't want to do that is money.
I can't understand the decision to "ship" with a potentially catastrophic failure that would cost many lives otherwise. I don't think this should be a dilemma. IMHO the two sensible options from a regulator point of view seem to be "make the plane safe to fly, and if that's expensive, tough luck" and "don't fly the plane".
It seems to me they could disassemble every Max, re-certify every part as stringently as they would certify a brand new part, throw away any part that was out of spec, then build "new" Maxes from those re-certified parts. (Except doing this would cost huge amounts of money.)
It's not enough to disassemble every Max. This wiring is the same on every single 737, of any model, that is in service. That's a much, much, much bigger effort, plus you'd be tearing apart airplanes that have been in service for decades with no incidents.
They did wire it correctly just the definition of correctly has changed over the last half century since the wiring harness was designed. It wasn't broke so they weren't gonna fix it because fixing things that aren't broke comes with cost and risk that you will break them when trying to fix them.
The repair or modification of wiring harnesses is often a risky repair.
I'm not an aerospace expert, but I know that even major automakers usually won't allow their dealers to do repairs to wiring harnesses because it poses too much risk.
Most mechanics are really bad at wiring. I watch them "fix" wires on those TV hotrod shoes, and cringe. (I used to do professional electronic assembly work, and at least I know how to solder properly.)
A popular topic on online car forums is electrical gremlins, almost always from crummy electrical repairs.
Sometimes I see a car where the lights on the rear of the car are wired incorrectly, and I can't understand how this could possibly happen. For example, backup lights (white/clear) are wired the same as the brake lights. The car didn't come out of the factory like that, so at some point someone must have "fixed" it and the result is that some lights come on at the wrong time. I'm amazed someone can look at that and say "yup, my work here is done"
Could have been an issue with a replacement part. One time I got a replacement headlight that was internally wired backwards from the factory. (High and low beams swapped)
JFYI, those are not necessarily wired incorrectly, car wirings are "queer" a single ground connection (negative/black to frame/body) that has oxidized or however does not make good contact and anything can happen to lights, and tail lights particularly also often suffer from dispersions/bridges in the connectorts due to the effects of humidity/mist[1].
[1] some makes/models are particularly subject to this (FIAT do you hear me?) , and it is very common to need to spray some WD-40 or similar once a year or so on contacts/connectors of tail lights/turn lights.
Safety is achieved by managing risk. Regulations are a derivative description thereof.
If the repair makes the plane meet the letter of the regulations but introduces risks that the regulations didn't consider, you've done a good job at meeting regulations but a bad job at managing actual risk.
The wiring, as it is, is considered unsafe and violates regulation. Boeing is trying to push the false dichotomy between leaving the planes as they are and "fixing" them introducing more risks.
In fact, there is another possibility: that the planes were never airworthy and should have never be flown in the first place and, if they can't be made airworthy, then they should be scrapped.
I am not qualified to judge the relative magnitudes of risk between the cable spacing issue and the rewiring issue. However, it is clear that they each pose some sort of risk.
Although, to play devil's advocate with Boeing's point: if you are to say that those planes are not airworthy because of their cable spacing, then no 737 is airworthy, as the regulation is new.
It sounds like the dilemma might be that facts support not pushing for a repair, but if they go with that they’ll be butchered by the media and the masses.
One of planes that prompted this regulation was their own Boeing 747-100 (TWA 800). They should adapt to the new wiring requirement when the regulation went in effect in 2009.
Expecting Boeing to regulate itself is like expecting a dog to not eat from its bowl when hungry. It ignores basic human nature and the incentives companies have to make profits at any costs, even if those costs are hundreds of human lives. I'm sure there are plenty of other things overlooked on this plane and others since the FAA gave up their oversight duties, their major reason for existence. When a company like this is unaccountable to anyone, we've seen what happens, yet there is still a question as to whether regulations should be enforced? How many more people need to die needlessly before the government steps in and does its job?
> “There are 205 million flight hours in the 737 fleet with this wiring type,” a Boeing official said. “There have been 16 failures in service, none of which were applicable to this scenario. We’ve had no hot shorts.”
This is appalling as this company exhibits the same excuses as before "there was no problem yet". Persistence in unfit behaviour at its best.
Whether this feature has been battle tested by a two hundred million hours running failure-free in production is beside the point. The point is to categorically eradicate the potential sources of failure in the aircraft's engineering. The point of regulation is not to arbitrarily erect hoops for manufactures to jump through. It's to ensure that aircraft are built as safe as possible. If one of my loved ones died due to this defect, as unlikely as that would be, I would not be satisfied with the explanation that "It never happened before in the previous 200 million hours, so no one deemed it worthy of fixing".
The point is not make airplanes “as safe as possible.” It’s to make them safe, while also balancing cost, fuel economy, maintenance, payload, etc. In this case, it is not clear that the actual safety risk is severe enough to justify the significant expense required to resolve it.
> The point is to categorically eradicate the potential sources of failure in the aircraft's engineering.
Then walk. Seriously. If you want to totally eliminate the potential sources of failure from flying, then walk. Drive. Take a rowboat. But don't fly, because you can never categorically eradicate the potential sources of failure in an aircraft - any aircraft.
> If one of my loved ones died due to this defect, as unlikely as that would be, I would not be satisfied with the explanation that "It never happened before in the previous 200 million hours, so no one deemed it worthy of fixing".
You probably also wouldn't be satisfied with "In our best estimate, fixing it was likely to introduce more problems than it solved", even if it was precisely the truth. But put yourself in the other position: If one of your loved ones died due to this fix, would you be satisfied with "But we eliminated the original failure possibility"? Somehow, I doubt it...
I'm not an idiot. I understand that there is always some risk in flying. My point was that the idea is to eliminate risks to the best of our ability. That should have been obvious by my post.
If we know there's a preventable risk, prevent it.
> You probably also wouldn't be satisfied with...
If that was the recommendation of the regulators, I'd accept that. I don't like the idea of manufacturers policing themselves. We have regulatory bodies precisely because we don't want companies making 'cost effectiveness' a factor in deciding which safety features to implement. Boeing attempting to circumvent regulations is how they ended up in this bind to begin with, resulting in many deaths.
> If one of your loved ones died due to this fix...
In what world would this be satisfactory at any level? I'm not sure exactly what your point is here. If the company is ordered by regulators to retrofit the aircraft to comply with new safety regulations we expect them to do it in a competent manner, don't we? That's not to say that I expect them to retrofit every existing 737... That's another matter entirely.
In software, one more-or-less generally-accepted result is that, when you fix a big, the probability of introducing new bug is somewhere between 20 and 50%. One would hope that it's much less for critical software, but it's not zero.
In the same way, what's the probability of introducing a new defect when replacing the wiring harnesses? It's not zero. It's never zero.
So the answer to "should we fix this issue?" is not "yes, of course". It's "will the fix make things better, or worse?" And of course, you don't know with certainty, but you make your best estimate of the probability of the new problem being worse than the old, and then you decide.
So even if "eliminating risks to the best of our ability" is in fact the right goal, that doesn't always equate to "eliminate this risk", even if we can do so.
> I don't like the idea of manufacturers policing themselves.
Here I agree with you completely. We've seen that movie; let's not watch it again.
> This is appalling as this company exhibits the same excuses as before "there was no problem yet".
Saying "there was no problem yet" about something that's only been in service for a relatively short time, yes.
Saying "there was no problem yet" about something that has been in service since the 1960s, not so much. If the FAA were to force Boeing to change this wiring on the 737 MAX, to be consistent, they would also have to change it on every single 737 of every model that is still in service--including many airplanes that have been in service for decades with no problem.
That's a very different argument from "the FAA skimped on the MAX before, so we shouldn't let them skimp on it again".
The situation is pretty clear. They need to fix the wiring issue. Stick to the regulation or don't regulate...
It's also shocking to me that the MAX may be rectified when depending only on one angle-of-attack sensor (the one that caused the two prior crashes). They should mandate that at minimum 2 redundant sensor must exist, at minimum. Really it should be 3 sensors for flight critical input, as has been the case for all modern airplanes.
> They need to fix the wiring issue. Stick to the regulation or don't regulate...
Fixing the wiring issue would mean fixing it on every single 737 in service, not just the 737 MAX. Many of those airplanes have been flying for decades with no incidents. Tearing them apart to rewire them might make things worse overall, not better, since any repair always has the risk of introducing some other problem.
Or they could straight up say "no, we're calling this a brand new plane now and it has to meet modern certifications instead of being granted grandfathered status on things"
> Fixing the wiring issue would mean fixing it on every single 737 in service, not just the 737 MAX.
And?
F.e., NHTSA has called the ongoing recall of airbags made by the major automotive parts supplier Takata "the largest and most complex safety recall in U.S. history.” Over 41.6 million vehicles have been recalled due to the faulty airbags.
Different makes, models, years - but faulty part is faulty part and millions of cars were recalled and fixed.
It's not a matter of the number of planes, it's a matter of not wanting to create more problems than you solve. The risk of that is much higher when trying to rewire a plane than when replacing an airbag in a car.
> Fixing the wiring issue would mean fixing it on every single 737 in service, not just the 737 MAX.
No it wouldn't as 737 was certified before the new regulation. It is in the article:
> That earlier 737 NG model didn’t have to meet the current wiring-separation standards because they came into force long after that jet was certified.
Just like with cars - you can drive a car from 70ties without airbags or crumple zones but you cannot buy a new car without airbags as it won't be able to pass the latest regulations.
Imo in this case the main issue is not the safety (seeing how the older planes aren't falling out of the sky) but setting a precedent where the certification authority has missed an issue which is not according to regulation - do the manufacturer gets a free pass or it is their responsibility to make the item according to regulation in the first place and it doesn't matter if it was missed during the certification process.
I know the previous 737 models were grandfathered. What I am questioning is the argument that, even though we accept this wiring flaw on all grandfathered 737s, it must be fixed on the 737 MAX just because Boeing made a different mistake (MCAS) on the 737 MAX. (If they hadn't made the MCAS mistake, the FAA wouldn't be reviewing the certification of the MAX and wouldn't have found the wiring issue.)
> setting a precedent where the certification authority has missed an issue which is not according to regulation
Is this the first time the FAA has missed a certification issue? I don't know, but I doubt it.
If the FAA has missed certification issues before, has the manufacturer always been forced to rework all affected aircraft when the missed issue is discovered? Again, I don't know, but I doubt it.
In any case, these certainly seem like relevant questions to ask before coming to a conclusion.
These sensors cannot possibly be expensive to build. Why aren’t there one hundred sensors on each plane? Trust whatever the majority of sensors report, notify that outliers need to be serviced.
Such are the externalities of taking the opinion "It isn't illegal if you don't get caught."[1] It is interesting that had Boeing not pushed the edge on the re-training re-classification rules they would not have had the crashes, nor the spotlight on them, nor this "new" problem.
As a result I have no empathy for managers who are not getting their bonuses this year, or executives who get fired, or corporations who have to take loans on unfavorable terms in order to weather the storm of consequences brought on by trying to avoid following the rules and incurring the expense such rules incur in their execution.
I do feel bad for the engineers who were fired or moved out of the company by pointing out that management wasn't following the rules. I do feel badly for the employees whose livelihood depends on their working on building these amazing machines being put out of work because the consequences are playing out. And I feel a little bit bad for the airlines suffering from carrying a bunch of planes they can't fly. Hopefully people are learning life lessons in this process and the pendulum will swing back into a safer mode of rule following from the current risk taking behavior.
[1] This philosophy, sadly way too common in my opinion, is that "rules" are for idiots, and since we're not idiots we need only concern ourselves with the risks as we understand them of why the rule should be followed, and ignore said rules when we believe we have no risk of both getting caught nor having the "bad thing" the rule prevents happening (at least on our watch while it would reflect on us.).
They've grandfathered other parts of the aircraft design that aren't nearly as controversial, so Boeing's argument, while predictable, has a little more merit than it seems at first.
Illegal seems like the wrong word for this sentiment as it's legal status does not depend on being caught. If I were to rob a bank, it would be an illegal act whether or not I'm caught.
The phrase reflects on “illegal” being an act for which you are punished by a court or regulatory authority. There is never any question that laws or regulations are actually being broken. View the phrase as exercising poetic licence and using “illegal” as a shorthand for “leading to a conviction and causing the actor to face punitive action.” The backwards logic is that I didn’t face punitive measures therefore what I did is not illegal.
Thus in your example robbing the bank is technically illegal but you aren’t going to court if you don’t get caught.
The normalization of deviance is a less cynical explanation (in the sense that it doesn't require the process to involve analysis of the risk of getting caught).
I’m seriously impressed that the distance between the source conductor, command conductors, and presumably return conductors is considered.
As a power systems and controls engineer we make
Some effort to separate wires carrying different voltages eg 24v and 480v, but positive and negative run in the same cables or conductors in the same raceway all the time with nary a second thought.
Is there something to be said or considered for the fact that the wires are in a dynamic system that might vibrate or chafe away insulation? I feel like that's a big part of the consideration in the separation criteria here, but I'm not an aviation or electrical expert at all.
The FAA and its sister agencies around the globe are very good at root-cause analysis. Where a single fault could cost many lives, there's strong incentive to follow any failure all the way back.
I'm guessing that your systems don't experience anything like airplane levels of vibration, or have anything like airplane numbers of fatalities if the controls fail, yeah?
In the US, the NTSB does root-cause analysis and makes recommendations to the FAA.
There’s a separation of concerns. The NTSB is solely concerned with finding out what happened. The FBI handles criminal investigations. The FAA is concerned with running air traffic control, regulations, and research.
they are turbine generators in hydro electric power plants - they are live buildings; the floor and walls are resisting all of the torque from the generators and the forces exerted by the water flowing through the building, and the machines are vibrating at 1 mm/s velocity or about 4/1000" displacement. So it isn't completely stationary, everything is just kind of humming and rumbling - unless there is a short circuit out on the power system and then massive forces are exerted on the generator and power conductors, or if the machine becomes disconnected from the power system and has 10 MW coming in and 0 MW going out it tends to speed up quite rapidly and shake a bit more - but for the most part I can't imagine any conductors wearing through their insulation, ever. No wires are ever exposed to sharp edges.
Those distances haven't been considered until real electrical shorts happened, safety standards are written in blood:
> The regulation was introduced in 2009 following study of two fatal crashes: TWA 800 in 1996, in which an electrical short is believed to have caused a spark in the fuel tank and an explosion; and Swissair 111 in 1998, when an electrical short caused a fire in the cockpit.
potential for an electrical short to move the jet’s horizontal tail uncommanded
I think this is a reference to the stabilizer, because the elevators are controlled by cable connected to the yoke and are hydraulically powered. Since stabilizer (trim) can overpower elevator force, uncommanded changes in this control surface could be really bad, depending on how a short manifests into control surface movements.
I can't assess the relative probabilities: a short happening vs the fix inducing some other problem. But I do wonder whether there's another way to mitigate it.
Today it's mitigated by the pilot. Runaway Stabilizer is a memory-item. [1]
This is the same memory item Boeing thought would mitigate MCAS, since that is essentially a runaway stabilizer trim, although in retrospect behaving in a very different manner making it much harder to diagnose.
Runaway Stabilizer / MCAS cases can be mitigated by the pilots (they can use cutoff switches and do manual trim), but not this kind of electrical short:
> Furthermore, the electrical power in that wire could circumvent the cutoff switches in the cockpit that, in the event of such a stabilizer runaway, are used to kill electrical power to the tail. Theoretically, the pilots could be unable to shut it off.
Since Boeing has taken the path of seeing what they can get away with the only appropriate response from the regulators is not to allow them the slightest deviation.
If the 737 Maxes can't be adequately fixed then send them back, refund the purchase price.
It's not enough to just regulate this on the 737 MAX. This wiring is the same on every single 737, of any model, that is in service. That includes airplanes that have been flying for decades with no incidents. Do you want to ground them all?
You're point is addressed already in the article when they stated that the original 737s were grandfathered in before the new regulation came into effect. So no, they've successfully gotten away with it on older models but I do agree with the GP that regulatory agencies need to set a firm precedent to deter other manufacturers from playi g fast and loose with the rules.
> the original 737s were grandfathered in before the new regulation came into effect
Yes, I know that. Presumably the same would apply to other aircraft models certified before 2009 (when the new wiring regulation was issued) that might have the same problem (as I posted elsewhere in this discussion, it's quite possible that other aircraft types certified before 2009 have the same problem--we don't know because nobody has looked).
However, if we're willing to not do anything to all those planes, even though we now know they have a potential issue, then we can't just insist on doing something to 737 MAX planes either, since the cost-benefit calculation in both cases is the same: we have a bunch of planes already in service, we now know there's an issue with them, do we fix it or not?
> regulatory agencies need to set a firm precedent to deter other manufacturers from playing fast and loose with the rules
For any 737 MAX aircraft that have not yet flown, I would agree with you. However, tearing apart aircraft that have already been flown to fix this issue might cause more problems than it solves. The teardown would be extensive and any repair that extensive risks introducing some other issue that didn't exist before and which could cause problems in the future. That makes it a different cost-benefit calculation.
I certainly agree that Boeing should not be the ones making that calculation. It would be nice if the FAA didn't either, but had some other agency such as the NTSB do the root cause analysis to estimate the relative risk of doing the repair on already flown planes vs. not doing it.
> The space shuttle also flew for along time without problems.
No, it didn't. There were plenty of problems prior to the flight that lost the Challenger, and plenty of problems prior to the flight that lost Columbia. NASA management just refused to pay attention to the engineers that were telling them there were problems.
I was absolutely shocked that only after the Columbia accident the underside of the craft was inspected in orbit. It shocks me that in more than a hundred flights, nobody in NASA management had enough curiosity to force someone to look for significant tile damage made during the ascent.
Learning how to build and fly things in air and space is pretty much the agency's job description.
Since the wiring standard under discussion here was only introduced in 2009, an obvious question is: how many other aircraft models currently in service, besides the 737 (and not just the MAX), have a similar issue that has not been caught simply because no updated analysis of their certification was done after 2009?
For once, I think Boeing does have a point here. This is the same wiring used on the 737NG, which AFAIK is considered the safest (or one of the safest, at least) airliner ever. The point about rerouting existing wiring introducing it's own potential hazard also seems like an entirely reasonable consideration.
I know it's automatic that we assume Boeing is either nefarious or retarded in everything they do, but it's hard to see this as that big a deal when considering the bigger picture.
These rules existed at the time Boeing built and designed this plane, no? And thus the plane was subject to these rules and Boeing never attempted to file for an exemption, correct?
Tough--they should have to rewire the plane.
They cut the corner (or missed the corner) and got caught. Too bad, so sad. Maybe fire a bunch of executives this time and I might have some more sympathy later.
> For once, I think Boeing does have a point here. This is the same wiring used on the 737NG, which AFAIK is considered the safest (or one of the safest, at least) airliner ever. The point about rerouting existing wiring introducing it's own potential hazard also seems like an entirely reasonable consideration.
"Nothing happened before" does not obviate the analysis that caused the rule to be created.
Aerospace rules are generally written in blood. Ignoring them tends to spill more blood.
This is exactly the kind of issue where your reputation is crucial. If your reputation is sterling, then nobody would blink about cutting you slack in this single instance. If, however, your reputation is such that there are likely even more instances like this that haven't been found, then you should get held to the letter of the law.
If they can't rewire it to standard without screwing up the insulation, then I guess they get to redo all the insulation as well. All their excuse is going to do is cost them even more money and time.
the same logic applies for new planes. Why should I be obligated to implement this new safety feature when I have build the ones before without it?
The MAXes where built after the regulation came into place therefore you better build it in. The same way you can't sell a new car without safety belts.
> You missed the point. It's not about the money, it's that rewiring might actually be less safe.
No, I didn't. That's what Boeing claims by attempting to extrapolate the safety record of a plane built under previous Boeing management who had safety as priority one to the safety record of the current plane built under Boeing/McDonnell management that prioritized money over safety.
The problem is that the previous wiring might be safe given that all the surrounding systems are also built to the same safety standard as the previous 737. Unfortunately, we have plenty of evidence that the surrounding systems probably are not built to the same standard.
In addition, the airplanes responsible for this rule coming into being didn't have a safety problem either--until they suddenly did.
> In addition, the airplanes responsible for this rule coming into being didn't have a safety problem either--until they suddenly did.
It's not that the planes developed a safety problem - it's that we learned that the wires being that close is a bad idea and that all planes built after we realized that should not make the same mistake.
If Boeing can't rewire the planes up to current safety regulations, then the planes should never fly again (since they should have never flown in the first place).
Even if the FAA cuts Boeing some slack here (which they shouldn't - these are safety rules that exist because hundreds of people had horrific deaths), the EASA will certainly not.
If the FAA accepts Boeing's excuse, they both would be liable in case the wiring causes an accident in the future, since both would have been negligent and knew fully well the wiring was not up to current standards.
Not to be pedantic but I believe the Airbus A340 is actually regarded as the safest airliner ever, with zero fatalities over the course of its nearly 30-year operational history.
There are several airliners, including models from Boeing and Airbus, that have had no fatalities. But they are low production models like the A340. It's arguably impossible to come up with a "safest" if you don't have some way to account for the fact that 20 times as many 737NGs have been produced as A340s.
It is strange to me that this article doesn't question the idea that Boeing and the FAA did not know before that the old wiring didn't meet current standards.
Of course they knew.
But it also seems that the old wiring design has been verified by the test of time and they have data showing the crashes weren't related to it.
So I think that ripping out all of the wiring on the planes and rushing to replace it with a new system, then rushing to test that new system, is the surest way to increase the likelihood of another system failure and possibly even kill off the Boeing brand if that happens.
Put it another way: do I rather fly with the wiring that was tested for 200M hours in the NG, or do I want the configuration that is retrofitted in a hurry to meet the standard? It’s not obvious that trying to “fix” this defect is a good idea.
Well they will say they can, if they are forced to. The question is: do I really think that the end result of that it is safer than something tested for 200M hours?
There is only one good “proof” of safety and that’s testing.
How do you know that the wire harnesses on the MAX are the same than on the NG? The only word we have for it is Boeings. As the planes are not identical, the wiring might not be identical as well.
It's always going to be boeings word. This is like a building permit - the applicant argues with drawings and technical arguments why their design meets the criteria (and quite commonly why their design is safe despite not meeting some specific criteria).
If you don't take a manufacturers word for something you can never get into any plane ever.
I don’t know about China but there is certain reciprocity between the US and Europe regarding airworthiness. [1] one of the damaging parts of the 737 MAX fiasco is it has caused many countries to rethink this agreement
Passenger planes make many flights per day, thus a lot of attention is made on the costs of usage (ie, the plane is not cheap to buy but it will be cheap to operate per flight).
Cargo plane fly mostly twice per day (base to sorting center and back), so they use older planes. They use more fuel per mile, but acquisition costs are low.
You can't just repurpose brand new planes for cargo use, it's not economically viable.
Plus, it would mean the safety of cargo pilots is less important than the safety of passengers...
Whenever it is approved, 737 MAX is likely going to be the safest aircraft that Boeing would have produced. There has been so much scrutiny after the past 2 crashes that at this point every remote possibility has likely been considered and taken care of.
On the other hand: There was so much hackery, bad engineering decisions, rush to market, cover-up and likely a lot more shenanigans that haven't yet come to light.
The whole engineering approach reeks of management mandating to "just fix it with gaffer tape", if it costs time or gets expensive.
Boeing's despicable behavior in the whole sordid affair also doesn't exactly help.
While I'm sure that there's a lot of scrutinity going into the recertification of the plane, such systems are so immensely complex that it begs the question: What else was missed?
I, for one, would be extremely reluctant to step into anything 737 after the NG. Even at the price to forego a direct connection.
A reorganization is possible but I really doubt the American government would allow Boeing to be truly imperiled. The US Military has thousands of Boeing aircraft, particularly all of the large tanker jets used for aerial refueling are made by or supported by Boeing (some were made by McDonnell Douglas, before Boeing bought them.) Some of America's military aircraft are even derived from the 737.
What about this is something that's too complicated to retrofit? Why would they even need to tear into existing wiring harnesses to fix this? Just run another wire through the new pathway isolated from everything else and decommission the old circuit by cutting the ends of the wire and slapping a heat shrink cap over them. Sure, fix the harness on new planes but is there really too much red tape to come up with a safe retrofit plan that doesn't involve messing with the existing harness?
That's likely a big part of the problem. Fishing a new wire is generally very difficult, and there are probably rules that say it has to be secured every X meters. Airplanes generally don't use much conduit, so I suspect they'd have to at least partially tear apart the plane to do this right.
There's a lot of misunderstandings in the comments here.
When you're dealing with complex wiring harnesses and wiring runs, there are always problems. For example, the A380 and one of Boeing's new airliners were delayed because stuffing the wiring harness in the nose didn't work.
In the case of airplanes, things flex and bend, causing wire chafing.
So there's no black and white answer to, "Is the wiring perfect?"
The only good solutions are:
1) When new airplanes are made, improve the wire layout
2) When old airplanes get a heavy maintenance check (D-check), possibly inspect and redo the wiring then.
3) Consider using conduit for safety-critical runs. Makes it harder to inspect, though. :)
Anyway, the Swissair 111 fire/crash was because of new gambling screens igniting flammable materials. Sure that was an electrical fire, but from adding entertainment equipment.
Swissair 111: "flammable material used in the aircraft's structure"
118 comments
[ 2.7 ms ] story [ 163 ms ] threadBut I would not trust Boeing to make that calculation and even the FAA's reputation has been dented (which is why I think they are being hard-arses about it) but it could be retrofitting is not the right choice.
I would probably be happier if the FAA and the ESA decided independently whether to allow it.
In this particular case the fact that it is aviation standards for wire separation at issue, when those are typically stupefyingly conservative, means that "doing nothing" may well be the safest course. But I am NOT an expert in this area, so don't trust me!
One way to help make the decision is to try and get money out of the equation. If the two options are "pay for the rework" or "pay a fine equal to the cost of the rework", then any company that opts for the fine might actually believe in that approach.
I get your point, but isn't it ultimately about money anyway? If they can wire a plane correctly when they're building it, they surely can rewire a plane later - they might have to remove more stuff, worst case scenario reverting the plane to the same state it would be for an original rewire, and I suppose the reason they don't want to do that is money.
I can't understand the decision to "ship" with a potentially catastrophic failure that would cost many lives otherwise. I don't think this should be a dilemma. IMHO the two sensible options from a regulator point of view seem to be "make the plane safe to fly, and if that's expensive, tough luck" and "don't fly the plane".
Similarly, if safety trumped all else, there would be no aviation industry.
I'm not an aerospace expert, but I know that even major automakers usually won't allow their dealers to do repairs to wiring harnesses because it poses too much risk.
A popular topic on online car forums is electrical gremlins, almost always from crummy electrical repairs.
[1] some makes/models are particularly subject to this (FIAT do you hear me?) , and it is very common to need to spray some WD-40 or similar once a year or so on contacts/connectors of tail lights/turn lights.
If the repair doesn't make the planes safe according to the regulations they should have been built for, then the planes need to be scrapped.
If the repair makes the plane meet the letter of the regulations but introduces risks that the regulations didn't consider, you've done a good job at meeting regulations but a bad job at managing actual risk.
In fact, there is another possibility: that the planes were never airworthy and should have never be flown in the first place and, if they can't be made airworthy, then they should be scrapped.
Although, to play devil's advocate with Boeing's point: if you are to say that those planes are not airworthy because of their cable spacing, then no 737 is airworthy, as the regulation is new.
Boeing is claiming that the service time of their wiring setup is sufficient evidence to justify an exception to applying the harsher model.
It is not an incredulous claim, and not a trivial dilemma.
This is appalling as this company exhibits the same excuses as before "there was no problem yet". Persistence in unfit behaviour at its best.
In fact, similar statements are valued in the aeronautical industry (engine failure rates, etc).
The Max failed much earlier than those 200Mi hours.
Then walk. Seriously. If you want to totally eliminate the potential sources of failure from flying, then walk. Drive. Take a rowboat. But don't fly, because you can never categorically eradicate the potential sources of failure in an aircraft - any aircraft.
> If one of my loved ones died due to this defect, as unlikely as that would be, I would not be satisfied with the explanation that "It never happened before in the previous 200 million hours, so no one deemed it worthy of fixing".
You probably also wouldn't be satisfied with "In our best estimate, fixing it was likely to introduce more problems than it solved", even if it was precisely the truth. But put yourself in the other position: If one of your loved ones died due to this fix, would you be satisfied with "But we eliminated the original failure possibility"? Somehow, I doubt it...
But you can make sure that the known potential sources of failures are dealt with.
I'm not an idiot. I understand that there is always some risk in flying. My point was that the idea is to eliminate risks to the best of our ability. That should have been obvious by my post. If we know there's a preventable risk, prevent it.
> You probably also wouldn't be satisfied with...
If that was the recommendation of the regulators, I'd accept that. I don't like the idea of manufacturers policing themselves. We have regulatory bodies precisely because we don't want companies making 'cost effectiveness' a factor in deciding which safety features to implement. Boeing attempting to circumvent regulations is how they ended up in this bind to begin with, resulting in many deaths.
> If one of your loved ones died due to this fix...
In what world would this be satisfactory at any level? I'm not sure exactly what your point is here. If the company is ordered by regulators to retrofit the aircraft to comply with new safety regulations we expect them to do it in a competent manner, don't we? That's not to say that I expect them to retrofit every existing 737... That's another matter entirely.
In the same way, what's the probability of introducing a new defect when replacing the wiring harnesses? It's not zero. It's never zero.
So the answer to "should we fix this issue?" is not "yes, of course". It's "will the fix make things better, or worse?" And of course, you don't know with certainty, but you make your best estimate of the probability of the new problem being worse than the old, and then you decide.
So even if "eliminating risks to the best of our ability" is in fact the right goal, that doesn't always equate to "eliminate this risk", even if we can do so.
> I don't like the idea of manufacturers policing themselves.
Here I agree with you completely. We've seen that movie; let's not watch it again.
Saying "there was no problem yet" about something that's only been in service for a relatively short time, yes.
Saying "there was no problem yet" about something that has been in service since the 1960s, not so much. If the FAA were to force Boeing to change this wiring on the 737 MAX, to be consistent, they would also have to change it on every single 737 of every model that is still in service--including many airplanes that have been in service for decades with no problem.
That's a very different argument from "the FAA skimped on the MAX before, so we shouldn't let them skimp on it again".
It's also shocking to me that the MAX may be rectified when depending only on one angle-of-attack sensor (the one that caused the two prior crashes). They should mandate that at minimum 2 redundant sensor must exist, at minimum. Really it should be 3 sensors for flight critical input, as has been the case for all modern airplanes.
Do you have a source for this? Last I read, there were 3 main categories of fixes, the first being to read both sensors.[1]
[1] https://www.businessinsider.com/boeing-737-max-mcas-fixes-20...
Fixing the wiring issue would mean fixing it on every single 737 in service, not just the 737 MAX. Many of those airplanes have been flying for decades with no incidents. Tearing them apart to rewire them might make things worse overall, not better, since any repair always has the risk of introducing some other problem.
And?
F.e., NHTSA has called the ongoing recall of airbags made by the major automotive parts supplier Takata "the largest and most complex safety recall in U.S. history.” Over 41.6 million vehicles have been recalled due to the faulty airbags.
Different makes, models, years - but faulty part is faulty part and millions of cars were recalled and fixed.
Replacing a faulty airbag on a car is a lot less complicated and risky than replacing many feet of wiring on an airplane.
No it wouldn't as 737 was certified before the new regulation. It is in the article:
> That earlier 737 NG model didn’t have to meet the current wiring-separation standards because they came into force long after that jet was certified.
Just like with cars - you can drive a car from 70ties without airbags or crumple zones but you cannot buy a new car without airbags as it won't be able to pass the latest regulations.
Imo in this case the main issue is not the safety (seeing how the older planes aren't falling out of the sky) but setting a precedent where the certification authority has missed an issue which is not according to regulation - do the manufacturer gets a free pass or it is their responsibility to make the item according to regulation in the first place and it doesn't matter if it was missed during the certification process.
I know the previous 737 models were grandfathered. What I am questioning is the argument that, even though we accept this wiring flaw on all grandfathered 737s, it must be fixed on the 737 MAX just because Boeing made a different mistake (MCAS) on the 737 MAX. (If they hadn't made the MCAS mistake, the FAA wouldn't be reviewing the certification of the MAX and wouldn't have found the wiring issue.)
> setting a precedent where the certification authority has missed an issue which is not according to regulation
Is this the first time the FAA has missed a certification issue? I don't know, but I doubt it.
If the FAA has missed certification issues before, has the manufacturer always been forced to rework all affected aircraft when the missed issue is discovered? Again, I don't know, but I doubt it.
In any case, these certainly seem like relevant questions to ask before coming to a conclusion.
They also require a computer that has the inputs for it.
Why they didn't go with three is probably a good question. Airbus did.
As a result I have no empathy for managers who are not getting their bonuses this year, or executives who get fired, or corporations who have to take loans on unfavorable terms in order to weather the storm of consequences brought on by trying to avoid following the rules and incurring the expense such rules incur in their execution.
I do feel bad for the engineers who were fired or moved out of the company by pointing out that management wasn't following the rules. I do feel badly for the employees whose livelihood depends on their working on building these amazing machines being put out of work because the consequences are playing out. And I feel a little bit bad for the airlines suffering from carrying a bunch of planes they can't fly. Hopefully people are learning life lessons in this process and the pendulum will swing back into a safer mode of rule following from the current risk taking behavior.
[1] This philosophy, sadly way too common in my opinion, is that "rules" are for idiots, and since we're not idiots we need only concern ourselves with the risks as we understand them of why the rule should be followed, and ignore said rules when we believe we have no risk of both getting caught nor having the "bad thing" the rule prevents happening (at least on our watch while it would reflect on us.).
Illegal seems like the wrong word for this sentiment as it's legal status does not depend on being caught. If I were to rob a bank, it would be an illegal act whether or not I'm caught.
Problem seems like an apt substitute.
Thus in your example robbing the bank is technically illegal but you aren’t going to court if you don’t get caught.
As a power systems and controls engineer we make Some effort to separate wires carrying different voltages eg 24v and 480v, but positive and negative run in the same cables or conductors in the same raceway all the time with nary a second thought.
I'm guessing that your systems don't experience anything like airplane levels of vibration, or have anything like airplane numbers of fatalities if the controls fail, yeah?
There’s a separation of concerns. The NTSB is solely concerned with finding out what happened. The FBI handles criminal investigations. The FAA is concerned with running air traffic control, regulations, and research.
> The regulation was introduced in 2009 following study of two fatal crashes: TWA 800 in 1996, in which an electrical short is believed to have caused a spark in the fuel tank and an explosion; and Swissair 111 in 1998, when an electrical short caused a fire in the cockpit.
I think this is a reference to the stabilizer, because the elevators are controlled by cable connected to the yoke and are hydraulically powered. Since stabilizer (trim) can overpower elevator force, uncommanded changes in this control surface could be really bad, depending on how a short manifests into control surface movements.
I can't assess the relative probabilities: a short happening vs the fix inducing some other problem. But I do wonder whether there's another way to mitigate it.
This is the same memory item Boeing thought would mitigate MCAS, since that is essentially a runaway stabilizer trim, although in retrospect behaving in a very different manner making it much harder to diagnose.
[1]: http://www.b737.org.uk/runawaystab.htm
> Furthermore, the electrical power in that wire could circumvent the cutoff switches in the cockpit that, in the event of such a stabilizer runaway, are used to kill electrical power to the tail. Theoretically, the pilots could be unable to shut it off.
If the 737 Maxes can't be adequately fixed then send them back, refund the purchase price.
Yes, I know that. Presumably the same would apply to other aircraft models certified before 2009 (when the new wiring regulation was issued) that might have the same problem (as I posted elsewhere in this discussion, it's quite possible that other aircraft types certified before 2009 have the same problem--we don't know because nobody has looked).
However, if we're willing to not do anything to all those planes, even though we now know they have a potential issue, then we can't just insist on doing something to 737 MAX planes either, since the cost-benefit calculation in both cases is the same: we have a bunch of planes already in service, we now know there's an issue with them, do we fix it or not?
> regulatory agencies need to set a firm precedent to deter other manufacturers from playing fast and loose with the rules
For any 737 MAX aircraft that have not yet flown, I would agree with you. However, tearing apart aircraft that have already been flown to fix this issue might cause more problems than it solves. The teardown would be extensive and any repair that extensive risks introducing some other issue that didn't exist before and which could cause problems in the future. That makes it a different cost-benefit calculation.
I certainly agree that Boeing should not be the ones making that calculation. It would be nice if the FAA didn't either, but had some other agency such as the NTSB do the root cause analysis to estimate the relative risk of doing the repair on already flown planes vs. not doing it.
No, it didn't. There were plenty of problems prior to the flight that lost the Challenger, and plenty of problems prior to the flight that lost Columbia. NASA management just refused to pay attention to the engineers that were telling them there were problems.
I was absolutely shocked that only after the Columbia accident the underside of the craft was inspected in orbit. It shocks me that in more than a hundred flights, nobody in NASA management had enough curiosity to force someone to look for significant tile damage made during the ascent.
Learning how to build and fly things in air and space is pretty much the agency's job description.
I know it's automatic that we assume Boeing is either nefarious or retarded in everything they do, but it's hard to see this as that big a deal when considering the bigger picture.
Tough--they should have to rewire the plane.
They cut the corner (or missed the corner) and got caught. Too bad, so sad. Maybe fire a bunch of executives this time and I might have some more sympathy later.
> For once, I think Boeing does have a point here. This is the same wiring used on the 737NG, which AFAIK is considered the safest (or one of the safest, at least) airliner ever. The point about rerouting existing wiring introducing it's own potential hazard also seems like an entirely reasonable consideration.
"Nothing happened before" does not obviate the analysis that caused the rule to be created.
Aerospace rules are generally written in blood. Ignoring them tends to spill more blood.
This is exactly the kind of issue where your reputation is crucial. If your reputation is sterling, then nobody would blink about cutting you slack in this single instance. If, however, your reputation is such that there are likely even more instances like this that haven't been found, then you should get held to the letter of the law.
You missed the point. It's not about the money, it's that rewiring might actually be less safe.
How much risk, I don't know. But slavishley following rules without bothering to understand them isn't a good idea.
Either those wires are safe, so leave them, or they are not, so rewire 6,000 grandfathered planes.
Doing some sort of hybrid where you rewire these planes, but not those, just based on the name, isn't logical.
The MAXes where built after the regulation came into place therefore you better build it in. The same way you can't sell a new car without safety belts.
No, I didn't. That's what Boeing claims by attempting to extrapolate the safety record of a plane built under previous Boeing management who had safety as priority one to the safety record of the current plane built under Boeing/McDonnell management that prioritized money over safety.
The problem is that the previous wiring might be safe given that all the surrounding systems are also built to the same safety standard as the previous 737. Unfortunately, we have plenty of evidence that the surrounding systems probably are not built to the same standard.
In addition, the airplanes responsible for this rule coming into being didn't have a safety problem either--until they suddenly did.
It's not that the planes developed a safety problem - it's that we learned that the wires being that close is a bad idea and that all planes built after we realized that should not make the same mistake.
Even if the FAA cuts Boeing some slack here (which they shouldn't - these are safety rules that exist because hundreds of people had horrific deaths), the EASA will certainly not.
If the FAA accepts Boeing's excuse, they both would be liable in case the wiring causes an accident in the future, since both would have been negligent and knew fully well the wiring was not up to current standards.
Of course they knew.
But it also seems that the old wiring design has been verified by the test of time and they have data showing the crashes weren't related to it.
So I think that ripping out all of the wiring on the planes and rushing to replace it with a new system, then rushing to test that new system, is the surest way to increase the likelihood of another system failure and possibly even kill off the Boeing brand if that happens.
The dilemma is real.
All they did was ensure their fix gets even more scrutiny and to require additional proof that it's safe.
There is only one good “proof” of safety and that’s testing.
If you don't take a manufacturers word for something you can never get into any plane ever.
Doesn't it require other agencies in Europe and China to do the same? How useful is a fleet that can't fly in large segments of the world?
[1] https://www.faa.gov/aircraft/repair/media/easa_us_roadshows....
Could they convert the entire fleet into cargo jets, or does the configuration not match that role?
Because pilots' lives don't matter?
If a plane isn't safe for passengers, it isn't safe for the crew.
Cargo plane fly mostly twice per day (base to sorting center and back), so they use older planes. They use more fuel per mile, but acquisition costs are low.
You can't just repurpose brand new planes for cargo use, it's not economically viable.
Plus, it would mean the safety of cargo pilots is less important than the safety of passengers...
For example, crew rest requirements adopted in 2010 don't apply to cargo: https://ttd.org/policy/ensure-one-level-of-safety-for-all-ai...
The whole engineering approach reeks of management mandating to "just fix it with gaffer tape", if it costs time or gets expensive.
Boeing's despicable behavior in the whole sordid affair also doesn't exactly help.
While I'm sure that there's a lot of scrutinity going into the recertification of the plane, such systems are so immensely complex that it begs the question: What else was missed?
I, for one, would be extremely reluctant to step into anything 737 after the NG. Even at the price to forego a direct connection.
Boeing will pay twice because their incompetence highlighted the incompetence of the FAA.
Not that I particularly care. I hope Boeing goes bankrupt.
That'd be said. I hope their top 3 or 4 management layers go to jail. For a long time. They've been criminally negligent.
That's likely a big part of the problem. Fishing a new wire is generally very difficult, and there are probably rules that say it has to be secured every X meters. Airplanes generally don't use much conduit, so I suspect they'd have to at least partially tear apart the plane to do this right.
When you're dealing with complex wiring harnesses and wiring runs, there are always problems. For example, the A380 and one of Boeing's new airliners were delayed because stuffing the wiring harness in the nose didn't work.
In the case of airplanes, things flex and bend, causing wire chafing.
So there's no black and white answer to, "Is the wiring perfect?"
The only good solutions are:
1) When new airplanes are made, improve the wire layout
2) When old airplanes get a heavy maintenance check (D-check), possibly inspect and redo the wiring then.
3) Consider using conduit for safety-critical runs. Makes it harder to inspect, though. :)
Anyway, the Swissair 111 fire/crash was because of new gambling screens igniting flammable materials. Sure that was an electrical fire, but from adding entertainment equipment.
Swissair 111: "flammable material used in the aircraft's structure"
https://en.wikipedia.org/wiki/Swissair_Flight_111
Source: commercially-rated pilot
It's true that the wiring harness is already proven with 737 NG. And it's probably true rewiring 737 MAX is a higher risk than doing nothing.
But IF this issue causes an accident without attempt to fix it, Boeing as a company might never recover. Even one such case could be enough.
So both not doing anything and fixing it carry a huge risk. Not fun to be Boeing these days...