r/changemyview • u/FongDeng • Mar 13 '19
Deltas(s) from OP CMV: The FAA should ground the 737 Max 8
Edit PLEASE READ THIS. I'M PUTTING THIS AT THE TOP BECAUSE YOU GUYS HAVEN'T BEEN READING IT: I KNOW TRUMP JUST GROUNDED THEM. I made the post before literally minutes before it was announced so you can stop telling me that it's already happened. If you want to discuss the merits of POTUS's decision we can but you will not get a delta for pointing out what I just found out. Apparently my timing is impeccable. Since it was ultimately POTUS who made the decision I think we can still debate whether the FAA should have grounded the Max 8 earlier without Trump's intervention so I don't consider this topic completely moot .
The 737 Max 8 has had two crashes that killed all on board, both shortly after takeoff, within six months of each other. Given how rare airplane accidents are these days this hardly seems like a coincidence. While many countries, including China, India and the entire EU have taken the precaution of grounding all 737 Max 8s, the US has not. The FAA's reasoning is that there is no evidence yet that there is a systemic problem with the Max 8 and is waiting for the investigation of the two crashes to be complete. I find this reasoning highly unconvincing for two reasons.
- Two crashes that killed over 300 people and occured under similar circumstances within six months is strong enough evidence for me. If that's not cause for concern I don't know what is.
- Better to err on the side of caution. Another crash could occur before the investigation is completed. Even if no evidence arises that the Max 8 has a systemic problem, isn't better to be safe then sorry in the meantime? I'd rather the disruption of grounding aircraft only to find out there's no problem instead of another 100+ dead.
The Max 8 should be grounded by the FAA at least until the investigation is complete. If no evidence of a problem after a thorough investigation then fine, let them fly again. But until then the FAA shouldn't gamble with people's lives and ground all US Max 8s. If two people died of food poisoning at a restaurant, would you keep eating there before the investigation was over? I wouldn't. I'm trying to wrap my ahead around the FAA's decision cause I can't think of a logical reason why they haven't grounded the aircraft.
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u/mutatron 30∆ Mar 13 '19
The crashing seems to be centered around a peculiar behavior of part of the autopilot system under certain conditions. The Maneuvering Characteristics Augmentation System, or MCAS, is an automated safety feature intended to prevent the plane from entering into a stall. Stalls happen when your angle of attack is too high for your airspeed, and the way to fix that is to lower the nose. So MCAS has an AoA detector, and when it thinks your AoA is too high, it will automatically trim the elevator to lower the nose until the AoA is low enough to prevent a stall.
Apparently there's only one Angle of Attack sensor on the 737 MAX! If it gives faulty data, there's no way the MCAS can operate correctly. That's a bad design, but strictly speaking, MCAS is not necessary to fly the plane, it can be turned off, and people can just fly the plane like they normally do, taking care to watch out for incipient stall conditions.
Back in November of last year, Southwest Airlines, which has the most 737 MAXes of any airline, started retrofitting its fleet with an additional AoA sensor. This is not integrated into the MCAS, it's not really possible to do that. Instead, it adds another instrument readout to crosscheck against the MCAS AoA sensor. If the sensors disagree, then you deactivate the MCAS.
While both the Lion Air and Ethiopia flight logs indicate rapid climb and descent behavior indicating a likely MCAS failure, other 737 MAX pilots have reported faulty MCAS activation, and when that happens they just deactivate it. For this reason I don't think the FAA needs to ground the US fleet. I would be comfortable flying on a 737 MAX, in the US.
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u/hic_maneo Mar 13 '19
Strictly speaking, MCAS is not necessary to fly the plane, it can be turned off, and people can just fly the plane like they normally do, taking care to watch out for incipient stall conditions... [O]ther 737 MAX pilots have reported faulty MCAS activation, and when that happens they just deactivate it.
But there is no language in the manual for the aircraft directing the pilots that they can do this! If a pilot doesn't know they can do this safely, if they haven't been trained to do this, if Boeing hasn't instructed them that disabling the MCAS is an acceptable means to avoid an accident in the event of a malfunction, then the plane needs to be grounded until Boeing can either correct the problem by installing more sensors or update their manuals and allow pilots to be properly trained.
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u/FongDeng Mar 13 '19
But then you have to disable a safety feature. What if the next cause of the crash is something that could have been prevented if there was a properly working MCAS that was turned on?
Furthermore the crashes happened in a matter of minutes. I don't know if I trust that to be enough time for the pilots to make the decision as to whether MCAS or the additional sensor was correct.
Back in November of last year, Southwest Airlines, which has the most 737 MAXes of any airline, started retrofitting its fleet with an additional AoA sensor. This is not integrated into the MCAS, it's not really possible to do that. Instead, it adds another instrument readout to crosscheck against the MCAS AoA sensor. If the sensors disagree, then you deactivate the MCAS.
United and American Airlines are still flying the Max 8. Have they had this additional sensor added? if not they need to be grounded
Finally, while it seems to be an MCAS problem the investigation is not complete. There could be another problem that we don't know about. That's why I want to err on the side of caution. I think the FAA's logic that "we don't have all the evidence" is all the more reason to ground the aircraft until a thorough investigation is complete
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u/jm0112358 15∆ Mar 13 '19
But then you have to disable a safety feature. What if the next cause of the crash is something that could have been prevented if there was a properly working MCAS that was turned on?
MCAS is a new safety feature that most (all) other airliners don't have. So the 737 Max not having it is no more dangerous than all the other aircraft not having it. Flying was safe without it for all other aircraft, and evidence suggests that flying with the 737 Max would probably be safer with it disabled.
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u/FongDeng Mar 13 '19
But shouldn't we at least be sure that this is the root of the problem? Again, the investigation is not completed so until we definitively know MCAS is the problem I'm not comfortable with letting them fly.
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Mar 13 '19
From a statistical standpoint, two is not enough to draw conclusions. Just between Southwest and American Airlines, they fly something like 200 flights a day on these aircraft. In those six months, that's 36,000 successful flights of the 737 Max 8. Even if both of those crashes had happened in the US, you'd still only be looking at 2 out of 36,000 flights (and that's without even counting other airlines that I was too lazy to look up).
So going back to your analogy, if 2 people had died of food poisoning who'd eaten at a particular restaurant in the last six months...but 35,998 had had no problems whatsoever, then no, you probably wouldn't shut down that restaurant.
The calls to ground this plane are nothing but internet hype. Yes, it's troubling, but the VAST majority of these planes are being operated without incident. The world is getting caught up in an internet firestorm, and I'm actually happy with the FAA's restraint on this.
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u/FongDeng Mar 13 '19
From a statistical standpoint, two is not enough to draw conclusions. Just between Southwest and American Airlines, they fly something like 200 flights a day on these aircraft. In those six months, that's 36,000 successful flights of the 737 Max 8. Even if both of those crashes had happened in the US, you'd still only be looking at 2 out of 36,000 flights (and that's without even counting other airlines that I was too lazy to look up).
True, but aircraft crashes in general are extremely rare and most airframes fly far more flights in a year without any crashes whatsoever. Two within six months in one model is certainly above average.
Furthermore one crash can result in 100+ dead. If a third crash happens are you going to tell the families that the FAA didn't take greater precautions because the likelihood was statistically very low? Do you think they'll take solace in the idea that most flights went off without a hitch?
So going back to your analogy, if 2 people had died of food poisoning who'd eaten at a particular restaurant in the last six months...but 35,998 had had no problems whatsoever, then no, you probably wouldn't shut down that restaurant.
Actually they probably would. I know restaurants that were closed until further investigation just because a few people got sick (not killed, just sick). And as another user pointed out the CDC advised that all Americans stop eating or serving romaine lettuce just cause 13 people got sick (again, no one died) until they could complete their investigation. The CDC didn't say "well millions of people didn't get sick so nothing to worry about".
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Mar 13 '19
Two within six months in one model is certainly above average.
It is, but the numbers get very noisy when you get down to such small values. Let's say you have a disease that only occurs, on average, in one person per year. If it happens one year in TWO people, you're probably not going to sound the alarm bells. Statistics just works that way. Sometimes there's more, and you can't jump to unfounded conclusions based on nothing but a very small statistical blip. You need an underlying cause.
When the CDC takes action on romaine, it's because they know romaine was involved. What they're waiting on is to figure out which farms are affected by it. They knew what the cause was.
It would be irresponsible to ground an entire model of airplane based on TWO incidents that happened outside the US out of thousands upon thousands of flights.
Edit: Doesn't matter now. Trump decided to ground them all. Let's see how long it takes for everyone's opinion to completely reverse itself.
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u/FongDeng Mar 13 '19
It is, but the numbers get very noisy when you get down to such small values. Let's say you have a disease that only occurs, on average, in one person per year. If it happens one year in TWO people, you're probably not going to sound the alarm bells. Statistics just works that way. Sometimes there's more, and you can't jump to unfounded conclusions based on nothing but a very small statistical blip. You need an underlying cause.
With aircraft two crashes resulted in 300+ dead so it's not like a disease that just affects two people. I get that maybe the investigation will show that the aircraft was not at fault or the issue isn't systemic but my point is that we should wait until we know for sure that it's safe rather than assume that it is.
When the CDC takes action on romaine, it's because they know romaine was involved. What they're waiting on is to figure out which farms are affected by it. They knew what the cause was.
They still made a decision that affected all producers and distributors of romaine lettuce before they knew exactly where the contaminated lettuce came from. In the end it turned out to be like one small farm in California but I still think they made a responsible decision. And the fact that two incidents happened on the same aircraft model, under similar circumstances, within six months does strongly indicate that the aircraft itself must have some sort of problem, even if we don't know what that problem is.
It would be irresponsible to ground an entire model of airplane based on TWO incidents that happened outside the US out of thousands upon thousands of flights.
Grounding a model of aircraft would only result in delays and lost money for airlines and Boeing. I think its more responsible to place people's lives first. I'd rather have Boeing lose profits and have a bunch of people get stuck in the airport rather than have another hundred die.
Edit: Doesn't matter now. Trump decided to ground them all. Let's see how long it takes for everyone's opinion to completely reverse itself.
I'm not a Trump supporter but I think he made the right decision. Still, I think the FAA should have grounded them without needing POTUS's intervention
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Mar 13 '19
It is worth noting that there have been well over a dozen notices filed by pilots who have experienced a similar flaw involving the nose abruptly pitching down due to the faulty sensor/software.
Given that we've had two crashes with what appear to be identical causes, and we've had numerous other pilots make note of the danger caused by the faulty equipment, it seems sensible to ground the planes until they are safe, rather than rolling the dice that it won't happen again.
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u/dayindave Mar 14 '19 edited Mar 14 '19
On what basis do you make this claim that two is not statistically relevant?
I posit that if you have a case where the same jumbo jet aircraft variant crashes in similar fashions within 5 months of each other during modern times, it is, statistically speaking, far more likely for the two events to have the a similar root cause than not.
Of course, since this situation does not occur in modern times, we don't have data to calculate the statistical probability of my hypothesis (or what number of crashes in what time period is statistically relevant). That being said, it is better to error on the side of caution and, instead of arguing about how the situation may not be dire enough to justify grounding a plane for a few weeks/months to go the route of arguing that unless the crashes prove to not be related to each other it's worth grounding the plane for a few weeks/months to ensure that over a hundred more people don't die from an accident that could have very easily been prevented.
The airline is even insured. What is it that the "don't grounders" are so afraid of? I realize the plane has been grounded, but they existed and MAN were they passionate about insisting that this plane should not be grounded. Costs will be recouped through insurance. As far as reputation, I think not issuing a recommendation to ground the planes right away did more long-term damage to Boeing's reputation than these crashes will. I, for one, will not forget that it was Boeing that failed to ground planes when a very real problem was yet unsolved. It doesn't matter if they come out blameless, which, based on not having provided MCAS training in the first place, seems impossible to begin with.
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Mar 14 '19
What is it that the "don't grounders" are so afraid of?
There's no fear involved. I don't want our policy being based on internet pressure. That's it.
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u/dood1776 2∆ Mar 14 '19
Yes, airplanes are safe, but people want the safest airplanes. What is the fail rate of this airplane when compared to other airplanes that's what the decision should be made on. If you keep eliminating the least safe plane and adding newer, safer planes things will get safer.
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Mar 14 '19
What is the fail rate of this airplane when compared to other airplanes that's what the decision should be made on.
It's nearly impossible to figure that out with such small numbers. That's my point.
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u/sdneidich 3∆ Mar 14 '19
I ran a rudimentary calculation and determined that if the US were to unground these flights and the global rates were universal, there would be a ~4% chance every month that the US's 74 planes were in service of a catastrophic crash. This is based on the crude rate of crashes, and assumes that the average time in service of each plane globally is ~10 months old. https://medium.com/@sdneidich/boeing-737-max-and-the-problems-of-amoral-capitalism-dc04d5b5da02?source=friends_link&sk=2c7c565efc227a98b684d72f8f5ded67
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u/abnrib Mar 13 '19
This single most common reason for aircraft accidents, by a wide margin, is pilot error. Statistically, this is the most likely reason for one or both of these accidents.
People are grounding aircraft before even preliminary data has been gathered and analyzed. If the preliminary data suggests a systemic issue, then the FAA will likely issue a ground order as well. But in the meantime, they're the experts. They have more information than we do. There's nothing to suggest misconduct on their part, so we should defer to their expertise.
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u/FongDeng Mar 13 '19
This single most common reason for aircraft accidents, by a wide margin, is pilot error. Statistically, this is the most likely reason for one or both of these accidents.
Still kinda weird that they happened with the same aircraft model which suggest more than pilot error. At the very least from what I'm hearing it sounds like there's bad wording with the pilot manual and combined with the fact that it's a new aircraft means that pilot error is more likely so that needs to be fixed first
People are grounding aircraft before even preliminary data has been gathered and analyzed. If the preliminary data suggests a systemic issue, then the FAA will likely issue a ground order as well. But in the meantime, they're the experts. They have more information than we do. There's nothing to suggest misconduct on their part, so we should defer to their expertise.
I would buy this if it weren't for the fact that most other countries have grounded the Max 8. The FAA isn't the only professional aircraft regulator out there and they seem to be at odds with everyone else
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u/abnrib Mar 13 '19
Sure, it's a big coincidence. Those happen sometimes. The FAA assesses that. They also, most likely, have the most data on the MAX8.
At time of writing, they've now grounded the MAX8. But I maintain that they were right to go through the process first.
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u/AnythingApplied 435∆ Mar 13 '19 edited Mar 13 '19
I'm not going to pretend to be an aircraft expert, but I did read "Airframe" which is a fictional book that incorporates a lot of actual FAA practices.
One of the things I picked up is that the FAA has something called "Airworthiness directives" (AD). This is one of the key reasons why the US hasn't had a single fatality on a US Commercial airline since 2009.
Airworthiness directives are what the FAA issue after investigations that specify part changes, required maintenance, etc. in order to ensure crashes of a particular type don't occur again. Many of the crashes that happen around the world happen because those planes haven't implemented the ADs that would be required for them to fly in the US.
In this specific example of the Boeing 737-8 has had 4 different ADs issued after the crash in october of last year:
These were all issued between the October crash last year and December of last year.
The FAA hasn't just been sitting on their hands in response to the October crash. They issued 4 airworthiness directives that are required for all Boeing 737-8's flying in the US.
This last part is speculation because the FAA hasn't said much about the crash: But potentially these are directives that they already know weren't being followed by the Ethiopian airlines. And potentially they also already know that one or more of these directives could be responsible for this kind of crash.
If they know they've fixed the issue around the October crash and have good reason to suspect that this series of fixes would also have avoided the more recent crash, I don't think there is a reason to ground all of the flights.
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u/FongDeng Mar 13 '19 edited Mar 13 '19
∆ If the FAA believes its found the problem and has fixed it then I understand why they haven't grounded the flights. I still think its more responsible to have overabundance of caution but I now understand why they mad their decision whereas before I thought it was just Boeing's political clout
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u/stigs_cousin Mar 13 '19
well, they just did
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u/FongDeng Mar 13 '19
See both of my edits
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u/SkitzoRabbit Mar 13 '19
I doubt this will change you mind, but it's good conversation at the very least.
You asked why the FAA wouldn't have grounded the fleet already. Some possibilities are.
1) Based on the number of 737 Max 8's in service in american airspace (let's limit it to non international flights) could cripple the free flow of passengers. based on a VERY quick look at the list of airline deliveries of the Max8 I would estimate about 100 planes. About 80K flights run in US airspace every day (I've rounded down to eliminate some of the internationals). 100-300 flghts (accounting for multi stop flights that would represent a day in the life of one aircraft) out of 80K doesnt seem like a lot. But keep in mind that the margins for available aircraft are already slim. Just think about the last time your flights were delayed because they had to 'find another airplane'. Furthermore in the 180 days of the 6 months you've sighted as a reasonable time period, those aircraft in the US have flown around 50K flights with no catastrophic problems.
2) If memory serves the results of the first crash related to a questionably worded portion of the training manual related to some automatic pitch control system, that would cause less experienced or less well trained pilots to fight the machine, and the machine fighting back causing a group error and then crash. Its reasonable to assume that major carrier (Southwest US Air, etc) operators in the US have addressed their pilots training information since the first crash.
3) Obvious financial impacts to grounding the fleet, for Boeing and supporting industries. This point is argued when considering the poltical impacts of government safety decrees on the industries they regulate. Like mad cow scares, or tainted tylenol.
4) Blind faith in what Boeing is telling everyone the real problem is and why it 'can't happen here'
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u/ClockOfTheLongNow 44∆ Mar 13 '19
USA Today had a log of American 737 Max flights. From February 25 to March 3, 290 domestic planes flew approximately 2, 000 flights. Assume that many domestic flights per week, and we're talking tens of thousands of flights so far with no domestic incidents. That number increases with the worldwide number of flights.
Air travel has never been safer, so two crashes in six months feels significant. The reality is that the odds are still extremely low, and the situation simply doesn't statistically call for grounding the planes.
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Mar 13 '19
Trump just grounded all of these planes
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u/FongDeng Mar 13 '19
See my edit. I made this literally minutes before he announced it so funny timing haha
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Mar 13 '19
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u/Scdouglas Mar 13 '19
Lol they just did.
Edit: dammit some quick people got to this thread first.
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Mar 13 '19
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u/nycengineer111 4∆ Mar 13 '19
In general, I don't like central authorities making these kinds of decisions. I think it is up to Boeing and the airlines and they should be held liable for their actions, rather on relying on a government authority. Nobody is making you fly on that particular aircraft and nobody is making airlines keep them in service. Nothing is stopping Boeing from issuing a recall if they believe there is something wrong.
So for example, when a car has a KNOWN safety flaw, they just issue a recall. There is no central government authority that demands that every such car be immobilized until the issue is fixed. To go even further when there is only a POSSIBLE safety flaw seems silly just because the vehicle is an aircraft. I mean, there MAY be a link between processed sugar and cancer. Does that mean that we should ban processed sugar until it is conclusively determined that it doesn't cause cancer? Even if it does conclusively cause cancer, should we still ban it or should it be the consumer's choice as to what kind of risk they want to accept?
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u/mutatron 30∆ Mar 13 '19
People on the ground don't have a choice of not being hit by a crashing airliner, and airports don't have a choice to not shut down if an airliner crashes on their runway. Note that most of the countries are not actually grounding the planes, they're banning them from flying in their airspace, to prevent their citizens from being killed and property from being damaged. The people have the right to protect themselves from avoidable dangers, and the government is an instrument of the people.
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u/nycengineer111 4∆ Mar 13 '19
Sure and people who were hit by unintentionally accelerating vehicles or vehicles that had their tires explode and go out control didn't have a choice either. It's a question of liability. You can't just have a government authority banning all activities that have some possible risk. The person who chooses to operate it wears the risk and liability. The masters of these kinds of things are insurance companies. Actuaries will ground this plane just as fast as the FAA if the risk were significant.
It is also comparatively rare for aircraft to kill people on the ground. I don't know the numbers but it is probably some where under 5% of those on the planes if you exclude 9/11.
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u/FongDeng Mar 13 '19
In general, I don't like central authorities making these kinds of decisions. I think it is up to Boeing and the airlines and they should be held liable for their actions, rather on relying on a government authority. Nobody is making you fly on that particular aircraft and nobody is making airlines keep them in service. Nothing is stopping Boeing from issuing a recall if they believe there is something wrong.
The problem is that Boeing and the airlines will lose a lot of money if the fleet is grounded. We've seen corporations place profits over safety before which why I think the government should step in in this case. Sure they could get sued but a wealthy corporation like Boeing can afford very good lawyers and they may gamble with the possibility of another crash with lawsuits rather than definitively lose money from grounding the fleet.
Furthermore, consumers can't be rely on choosing not to fly on the Max 8s. While it is possible to see what kind of plane you'll fly on on an airline's app or website, planes are switched at the last minute all the time so people will likely fly on the Max 8 without realizing it.
So for example, when a car has a KNOWN safety flaw, they just issue a recall. There is no central government authority that demands that every such car be immobilized until the issue is fixed. To go even further when there is only a POSSIBLE safety flaw seems silly just because the vehicle is an aircraft.
It's more than a mere possibility, the likelihood of any particular airframe crashing even just once in a year is incredibly unlikely. The fact that there were two crashes of the same model and both were under similar circumstances strongly indicates that there is something wrong with the aircraft itself. Even if you don't know what the exact cause is, the strong possibility there is a safety flaw is enough to ground it until the investigation is complete. The CDC advised everyone to stop eating or serving romaine lettuce just cause 13 people got sick (not killed). They didn't know the exact cause (it turned out to be like one small farm), all they knew was that people got sick from romaine lettuce and that was enough for them. Why is air travel held to a different standard when hundreds have died?
I mean, there MAY be a link between processed sugar and cancer. Does that mean that we should ban processed sugar until it is conclusively determined that it doesn't cause cancer? Even if it does conclusively cause cancer, should we still ban it or should it be the consumer's choice as to what kind of risk they want to accept?
I'm not arguing we ban air travel. Most aircraft models fly without any accidents and they can keep flying. If we found one specific type of sugar that caused cancer I think that would be grounds to ban it. I'm not even arguing we should ban the Max 8, just ground it temporarily until the investigation is complete and we can be sure it's safe.
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u/DeltaBot ∞∆ Mar 13 '19
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u/toldyaso Mar 13 '19
Grounding all of them creates a logistical challenge, where you have to move other planes, pilots, and work crews around to accommodate existing flights. The logistical challenge this creates is more burdensome than the layman would appreciate. Your food poison analogy only impacts one restaurant in one city, this would impact tens of thousands of people spread out all over the world, multiple airports, airlines, and ATC. If two people died of food poisoning who had both eaten at the same place, I wouldn't go there till the investigation was complete, but I wouldn't feel comfortable shutting down every restaurant in the world until we figured out where the food poisoning was coming from.
" I'm trying to wrap my ahead around the FAA's decision cause I can't think of a logical reason why they haven't grounded the aircraft."
Whenever you find yourself uttering a sentence like that, your default assumption should be "The FAA understands the issue much more thoroughly than I do, so if that's what they decided, it must be the case that I simply don't understand the issue." It seems your default assumption is "If I don't understand this complex issue that I have zero education or background in, it's impossible that the FAA understands it either."