How to quadruple your productivity with an army of student interns - <AUTHOR> http://blog.ksplice.com/2010/03/quadruple-productivity-with-an-intern-army/ <comment><USER2> I think the key to this really is "Design your intern projects in advance".

I interned last summer at Siemens Energy, working on internal software. Well, sort of working on internal software. My manager didn't have a project ready for me on my first day, then it took him a few weeks to pull something together. When he did, I was done within two weeks.

I was useful, effective, and efficient on the project I was given. Yet because my project was not designed in advance, I was stuck sitting around in the office for much of the summer and felt like a waste of Siemens' money.

<comment><USER3> That seems to be the typical experience of most contractors.

</comment></comment><comment><USER4> The photo showing everyone at work looks like it would difficult to concentrate and rife with distraction. Why do companies feel the need to treat their developers like this? I understand that they wanted to get their projects done quickly, but it seems like that would be a tough place to work.

Hopefully the interns were paid well (this is relative) and learned a lot.

-JP

<comment><USER5> When I first saw the photograph of the interns' office, I thought that the article was a joke. I really don't understand how anybody could program productively under those conditions.

<comment><USER6> Crowded offices can be good for climbing a learning curve. The biggest problem most of the interns would face would be setting up their systems, getting the build to work, and figuring out how to integrate stuff into the system.

Lots of communication is good for that.

If they needed to do any deep thinking, I hoped they would have been allowed to work from home for a day.

<comment><USER7> _Crowded offices can be good for climbing a learning curve._

Exactly my experience for my first internship, though it was far from _that_ crowded. We picked up C# and a large framework (and some, a second language) well enough to be productive in a week and a half. (my top-level comment has more details)

</comment></comment></comment></comment><comment><USER8> Last year, I was approached by two Dutch trainees (20 and 22 yo) who wanted to do their trainee placement abroad. I agreed without having done more than trade a handful of emails with them.

They came to Australia and worked for me for five months. They brought their own laptops so I only had to provide a couple of desks, second monitor for each and a chair. I paid them in accordance with a typical traineeship for them back home (about AUD150/week, which would be around USD135/week). Their rent (at the place of a friend of mine) was AUD100/week and they supplemented their living costs with savings and help from their parents.

They were pretty raw as web designers and HTML/CSS guys but got a lot of opportunities to learn new skills and fill gaps with simpler work. Generally, they had paid for themselves each week by the end of each Monday. They loved the experience (we do drink beer and play a lot of table tennis here at the office!) and it worked really well for me also.

I am a general web studio first and foremost but was able to use them on various side projects as well - cutting PSDs to HTML, doing logo and page concepts, general maintenance, etc.

Their supervisor is looking to send more over later this year - they have intakes (outtakes?) in February and September. Will definitely be doing it again.

Worth echoing caryme's comment about designing intern projects in advance. With a sudden boost in manpower to a small business (I'm a sole director with two employees normally) you can quickly burn through work and have time to kill. In those times, it's good to have a few side projects you've been meaning to start. As a sole founder, try not to leave yourself as the chokepoint if you can avoid it.

Happy to answer any questions about it if people are interested.

</comment><comment><USER9> "Nothing is impossible for the man who doesn't have to do it himself!"

I heard this intern intensive approach is quite popular with large tech companies in China, where up to half of the workforce could be interns.

</comment><comment><USER7> My first internship had 6 of us sitting around a table, churning out code, just after my freshman year. Best thing I've done for my programming, easily. The supervisor did a good job bringing us all up to speed, and we ended up picking up C# and their framework in about a week and a half (they had a huge codebase already), and some of us learned Progress in the same time period (old english-like query & character-UI language).

The important parts for us to being up and running quickly, and being productive? Nearly full-time access to one of their main developers for the first two weeks, they knew precisely what was needed (lots of similar code, but not similar enough to DRY up), and _we were in the same room_. For at least half the summer, we were throwing questions back and forth every couple minutes when we couldn't remember something, and the vast majority of the time one of us would remember. Immediate question & response was absolutely invaluable, and I think was the single most important tool to speed-learning what we needed to know. As time went on our tasks diverged and we knew more, so we didn't need questions answered as often, but it was massively useful at the beginning.

Of course, it didn't hurt that they paid quite well. Motivation is always useful.

</comment><comment><USER10> when you say 'student', you mean low-paid, right? Last I looked, it was illegal to have unpaid interns working on anything your company might actually use to generate income.

<comment><USER11> Really? I didn't know that. Reference? Not an issue for me, but seems odd to me somehow....

<comment><USER12> This was a real surprise to me too. Here's some discussion I found:

[http://www.onedayoneinternship.com/blog/are-unpaid- internshi...](http://www.onedayoneinternship.com/blog/are-unpaid-internships- illegal/)

I figured that if you were getting paid _nothing_ while working on something profitable for a company, it was assumed you were being compensated with experience. But apparently, all the company can do is train you while deriving zero benefit from your training. This seems like a stupid law.

<comment><USER13> I believe that the law is there to prevent companies from calling ordinary employees "interns" for the sake of getting around minimum wage laws.

<comment><USER14> Turning the perspective around, minimum-wage laws can be seen as having the purpose of preventing low skilled people from learning on the job. One of the best ways to learn is take a job is the field you want to learn in. You get paid to learn. This is better than having to pay to learn. Unfortunately minimum-wage laws make this option available only to people who already have enough skills that they can produce at least minimum-wage value while learning. So an MBA-level person can take a manager's job in a restaurant for low pay to learn restaurant-managing skills, but a high-schooler may not be able to take a cook's job to learn basic job skills like showing up on time, being diligent, following directions, etc. because the high-schooler may not be producing enough net value to justify even minimum wage.

</comment></comment></comment></comment></comment><comment><USER15> Awesome headline; I bit, thinking this would be a spoof on 37Signals or Tim Ferriss.</comment>


Settle a dispute: Is the Google CR-48 a good looking device? - <AUTHOR>

A few friends of mine and I got into an argument about whether or not the CR-48 was a good looking device or not. So have your say, Is it sexy? is it disgusting? is it a Macbook ripoff?<p>If you haven't seen it yet heres a link with loads of pics. http://www.thechromesource.com/a-collection-of-cr-48-photos-by-users/ <comment><USER2> I love the looks and feel of mine.

</comment><comment><USER3> I think it does look good; nice clean sleek black finish.</comment>


U.S. to ground Boeing 737 Max 8 - <AUTHOR> https://www.businessinsider.com/us-bans-boeing-737-max-8-after-ethiopian-airline-lion-air-crashes-2019-3 <comment><USER3> This is the correct move. Airline crashes are so rare that two crashes of a new model within 6 months of each other must be cause for grounding flights.

The fact that Boeing cut as many corners as they did to bypass mandatory training just adds more smoke to the fire. When the dust settles on this episode I won't be surprised to learn that Boeing (and FAA regulators) is found completely at fault for engineering shortcuts to save costs on re- training.

<comment><USER4> I think we should be careful to look wholistically at this. Will grounding the plane cause more people to drive? Driving is so much more dangerous than flying even if there's a MAX crash every 6 months (doubtful). How many more people will take connecting flights — the danger is in the take off and landing after all. I don't have the answers, I'm suggesting this isn't a straightforward decision. Humans have an amazing ability to overweight incredibly unlikely outcomes with severe consequences.

Some napkin math. 150,000 flights, each with 172 seats (based on the American Airlines 7M8 configuration, which is admittedly tight). That's 25.8 million journeys. Two accidents, let's that's ~350 deaths. Your chance of dying on any given journey is therefore 0.00135% (four nines to live).

You've got a 0.0167% chance of dying [1] for every 10,000 miles driven. Let's assume that each 7M8 journey averages 2500mi (generous, a transcontinental average). A linear projection tells me that's a 0.004175% of dying in an equivalent car ride.

You're still 3X safer on a 7M8 than you are in your car.

Now, by no means should this be taken to say the planes shouldn't be fixed or that Boeing should "get away with it." However, grounding all these planes and pushing people into a less safe form of transit may actually end up causing more harm than allowing the planes to fly with a fixed, short schedule to resolving the problem.

[1] [https://www.seeker.com/how-common-are-skydiving- accidents-17...](https://www.seeker.com/how-common-are-skydiving- accidents-1765419215.html)

<comment><USER5> > _" Driving is so much more dangerous than flying even if there's a MAX crash > every 6 months (doubtful)."_

I'm not sure that's correct. Let say there's 350 MAX aircraft in service, flying 5 flights per day on average. In 6 months, thats about 320,000 flights. So a 1 in 320,000 chance of a fatal crash. Let's say the average route length is 1000 miles. That's 1 crash per 320 million miles flown, or 3.125 crashes per billion miles flown.

If we assume an average of 150 passengers per flight, then it's _468 deaths per billion miles_ for the MAX, compared to only 0.02 deaths per billion miles across all aircraft. [1]

In the US, there are 12.5 deaths per billion miles driven, including pedestrian and cyclist deaths from motor vehicle collisions.[1]

If it crashed once every 6 months, the MAX would be around _37X_ more dangerous than driving, and _2340X_ more dangerous than an average commercial flight in the United States.

[1] [https://en.wikipedia.org/wiki/Transportation_safety_in_the_U...](https://en.wikipedia.org/wiki/Transportation_safety_in_the_United_States)

<comment><USER4> 150,000 flights, 172 seats per is 25.8 million passenger seat-journeys. Given the type, I think it's fair to say they're at least 1200mi long (why fly a 7M8 on a sub-2 hour flight, when you can just throw a regional jet at it). The whole point of the MAX family is that it can fly further than a normal variant. This is 30.96 billion passenger seat-miles. There were ~350 deaths. This is 0.000000011 deaths per passenger seat-mile, or 11 per billion. This is in line with but still less than driving (12.5 per your data source).

I imagine 1200 miles is short for an average 7M8 flight though, which could make it substantially safer. With 2500 mile averages you get back to that 3X number I cited. It's still no more a death trap than your average Honda Civic (10% safer by your metrics, more by mine).

To your point, it is of course riskier than a different aircraft.

My whole thesis was to ask what effect this will have across the entire population and how will humans react, irrationally, to this news.

<comment><USER6> There are arguments against measuring crash rates by "number per vehicle miles traveled" and instead by "number per vehicle hours traveled." VMT is a product of speed and time, and thus a fatalities-per-VMT metric will nearly always show the faster routes to be safer.

But compare spending 20 minutes traveling 10 miles on a local street, vs 10 minutes traveling 10 miles on a freeway. Both are considered equally safe using a fatalities-per-VMT model. But in the former, you've stayed safe for a longer portion of your life. (See [http://pedshed.net/?p=1050](http://pedshed.net/?p=1050))

Using that metric would make that Boeing far less safe compared with driving.

<comment><USER7> But you travel to get somewhere not to be in a vehicle for X amount of time. So why would any metrics besides per-distance be more relevant.

<comment><USER8> As a traveler, I care about the trip, not the time nor the distance. If I take this trip, what's my probability of dying if I fly it versus drive it.

Airplane travel have fixed segments (takeoff and landing, ascent, descent) and variable segments (the coasting phase that varies by distance traveled). Car travel is only the variable segment. Hard to compare apples to oranges.

</comment></comment></comment></comment></comment></comment></comment><comment><USER9> They had no choice. When no other major regulator would stand with their position, and the public didn't wish to fly on the Max 8, the position became untenable.

After the flight data recorders are recovered from the Ethiopian Airlines accident they could reevaluate if it turned out to be something else. But this seems like a rational safety first position given what we know today.

Hopefully Boeing's April patch and mandatory additional training mitigates the issue well enough to resume normal flight operations.

<comment><USER10> The fix may be as simple as a patch, but the customer confidence in the plan is damaged, maybe beyond repair.

I know I will look twice next time going on a trip which plane I end up on, I'm not sure I will go with a 737 Max anytime soon.

<comment><USER11> Remember all the early A320 crashes? Do you worry about stepping onto an A320 now? Unless the problem turns out to be far deeper, I suspect that this, too, shall pass.

<comment><USER12> It doesn't look like anything like the 737MAX crashes though: [https://en.wikipedia.org/wiki/List_of_accidents_and_incident...](https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_the_Airbus_A320_family)

"an a320 crashes every two years" sounds quite different than "a brand new 737MAX crashes during take off every 6 months because of the faulty sensor thingy".

Also a320 family of 8605 aircraft took the life of 1393 passengers in 30 years, 737MAX is at %30 of that in two years and 350 aircraft.

737MAX accidents look very brutal and specific. It doesn't look like "ironing out imperfections" but more like "this plane is broken, it falls off on take off" \- regardless if that's the case, people see a pattern here.

<comment><USER13> Worth noting: 150 of the A320 count may be Germanwings Flight 9525 (unless you already accounted for this) - which was suicide by pilot.

Not really fair to blame the plane in that case.

<comment><USER14> It's not fair to blame the plane at all unless you're sure the crash was the plane's fault, but that isn't stopping most of the people in this thread from doing it.

<comment><USER15> Airplanes don't have the right to a trial of their peers with presumption of innocence.

Two crashes within six months is very abnormal. Abnormalities are evidence of problems. Airline regulators are tasked with keeping people from dying, not with protecting manufacturers' feelings.

<comment><USER14> The Boeing 767 experienced _three_ crashes between the months of September 2001 and April 2002. I think you can guess what caused the first two.

You need more information than just a calendar and a model number to make determinations of flight safety.

<comment><USER16> > I think you can guess what caused the first two.

You do realize they redesigned the plane after 9/11 to prevent that from happening again, right?

<comment><USER14> Yes but my point is that people don't avoid the 767. Look upthread please, this whole sub thread is about whether these incidents will cause consumers to avoid 737 Max planes in the future.

My (apparently very controversial) opinion is that we don't know enough to predict that now, because we don't know what caused the Ethiopian Air crash yet.

<comment><USER17> People never avoided the 767 because it was clear all along that the crashes had noting to do with the plane.

People are avoiding the 737 MAX because given the current information it definitely _could_ be a problem with the plane, in fact the information we already have from the first crash makes it look like it's _very likely_ to be a problem with the plane.

You option is not controversial, it's just wrong.

<comment><USER14> > People are avoiding the 737 MAX because given the current information

Again: the topic here is predicting long-term damage to consumer confidence. I understand what is happening right now.

The entire 787 fleet was grounded not more than a few years ago due to battery issue. How many people actively avoid 787s today? Long-term consumer trust depends not just the root cause of an accident, but also the perception of how it was addressed. As the GP correctly points out, the 767 (and all other planes, and security screening procedures) were redesigned to protect against the type of attack that succeeded on September 11.

</comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER18> Good lord, this has been such a disaster for the FAA's image. Slower than everyone else to ground the plane _and_ they project the appearance of being susceptible to political winds. Not a good look.

<comment><USER19> Isn't it more that the rest of the world is susceptible to political winds (US plane) and the FAA is just holding the course?

<comment><USER20> A plane crashes and kills over 300 people, in two separate incidents, in an industry where even minor crashes are rare, and you think the grounding of the planes is "political"?

<comment><USER21> FAA is not in the business of operating based on unsupported assumptions. The investigation for the second crash is not complete and a root cause is not known.

<comment><USER22> If a third 737 Max 8 were to crash before a root cause of this crash can be determined, would you then say it's a prudent move to ground them all? What about a fourth? Fifth?

Is your position that _any_ grounding of the planes is unjustified until the full root cause is determined, or that _" only"_ two crashes isn't enough to justify this action?

While I would always rather understand root cause -- and it's absolutely essential to get there eventually -- the world is full of imperfect information and assumptions are sometimes all you have.

<comment><USER23> One inexplicable crash is not a case for grounding, no; otherwise the (incredibly safe) 777 would still be grounded because of MH 370.

Regarding the 737 MAX now, the prior Lion Air crash is reasonably well understood. It has exposed some fundamental weakness and questionable design choices, but the plane was still deemed safe to fly.

Thus, what we have is one unexplained crash. Why should it be grounded?

(Having said that, I'm avoiding the MAX as far as I can. But that's based already on the Lion Air crash. So, I argue that it should've been grounded after Lion Air became understood, or not at all.)

<comment><USER24> We have one unexplained crash where early reports about what happened /strongly/ match the circumstances that brought down the LionAir flight. We also have hundreds of public complaints from pilots across the United States of similar unexpected nose down behavior from 737 MAX airplanes.

<comment><USER23> Oh, I hadn't heard of those reports. It must be terrifying when your plane is actively trying to kill you.

I don't understand how they could build MCAS on the basis of one (!) AoA sensor.

<comment><USER25> It's one sensor per flight computer, and the diagnostic indicator to warn a pilot of disagreeing AoA sensors is a paywalled upgrade.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER26> An interesting point was made by an airline pilot in one of the plane forums. It appears that Max 8 with full trim deflection down doesn't have enough controls authority to recover (at least in the syms). Thus, the trim issues followed by disabling the trim can lead into a situation when pilots can not recover the plan from steep descend. Of course, this is not necessarily what have happened in real life and we need to see the data.

<comment><USER27> Pilot here. Correct, in most aircraft that incorporate a trimmable horizontal stabilizer, elevator authority will be insufficient to counteract the aerodynamic effects of a the entire tailplane having deflected through a certain point. Thus it is important to quickly recognize and correct a runaway trim situation.

Of even more significance is that is currently unclear if it is even possible for a pilot, once it has disengaged the trim motors (following faulty commands from MCAS) to manually correct the trim as per Boeing procedure [1].

The problem lies in the fact that it makes a lot of sense to haul back on the yoke as hard as you can if the nose starts dropping. Elevator upwards deflection loads the tailplane aerodynamically in such a way that it becomes harder to trim the tailplane in the required direction. Called colloquially a yo-yo maneuver, you are then require to "offload" the tailplane (think - <USER2> yoke forward..) in order to be able to manually correct the runaway trim.

Plane going nose down, push yoke forward at 500ft? I do not envy the crews at the pointy end of those flights. My heart breaks just thinking about it.

The Lion Air pilots must have been pulling back on the sticks until their tendons break, to no effect. I hope there is a special place in hell for Boeing execs.

[1] 737 Flight Crew Training Manual, chapter Non-Normal Operations/Flight Controls, sub heading Manual Stabilizer trim:

"Excessive air loads on the stabilizer may require effort by both pilots to correct mis-trim. In extreme cases it may be necessary to aerodynamically relieve the air loads to allow manual trimming. Accelerate or decelerate towards the in-trim speed while attempting to trim manually."

This was recently brought to the attention of members of a certain pilots forum that does not welcome lurkers, hence not adding a link.

<comment><USER28> Would it be inappropriate to ask for an explain-like-i'm-5 version of this?

<comment><USER29> Maybe not quite 5-year-old, but here's my attempt:

The elevator is the little wing at the back of an aircraft that tilts up and down to make the nose go up and down. When the pilot is flying, this up-down is what moving the yoke forward/back does.

The elevator also has a tab (the trim tab) part of the wing that can move independently from the main part. This trimming movement allows for adjustments to the plane's up/down movement that don't require the yoke forward/back (this is useful to "lock in" the current desired climb/descent/level flight so that pilots don't have to be constantly pushing/pulling on the yoke to get the plane to be climbing/descending/level the way they want it).

The 737-MAX has a system that automatically uses this trim tab to pitch the nose of the plane down when it senses certain conditions, without notifying the pilots. In this case (plane inexplicably pitching down), the natural response from a pilot is going to be to pull back on the yoke to counteract.

This can cause issues because the act of pulling back on the yoke increases the pressure on the elevator (because physics - the more the elevator deflects in an attempt to change the plane's attitude, the more force the airstream flowing over it exerts. This "catching the airflow" is why it can change the plane's attitude at all). Apparently on this plane if the trim tab is way out of line even if disconnect the erroneous system that was automatically adjusting the trim tab and try to reset the trim to a safe position by hand, the airflow over the "loaded" elevator (which is trying to counteract the position of the trim tab and keep the plane from crashing) is too strong to physically allow the manual control to move the tab. So the "correct" procedure is to push the yoke in (allowing the nose to go down/lose altitude) to reduce the airflow that's hitting the elevator, while frantically spinning the manual trip wheel to get it back to neutral. Then, once you've reset the trim manually, you presumably pull back on the yoke to get the nose up and pull the plane out of the dive.

The issue with that is that the ground can get in the way in between when you've let off the yoke and you've spun the wheel enough to get the trim tab back to neutral.

<comment><USER27> Incorrect, this describes a typical General Aviation aircraft with trim tabs. Most (all?) airliners use a trimmable tailplane, meaning the entire tailplane tilts up and down to trim for a specific speed.

<comment><USER30> _Incorrect, this describes a typical General Aviation aircraft with trim tabs. Most (all?) airliners use a trimmable tailplane, meaning the entire tailplane tilts up and down to trim for a specific speed._

The only airliner I can think of that uses trim tabs is the DC-9 and its derivatives (MD-80/MD-90/Boeing 717). Some, like the L-1011, went in the completely opposite direction and use an "all moving tailplane" where the functions of the elevator and stabilizer were integrated into one piece.

</comment></comment></comment></comment></comment></comment><comment><USER27> The current "industry standard" is 1 accident per 10 million flights. I think the MAX 8 has racked up something around 150K flights with 2 accidents. So yes, the statistics represent an anomaly.

<comment><USER31> Naive null hypothesis: ~0.8% that MAX 8 is as safe as other planes and the shared accidents are a coincidence.

<comment><USER32> I assume you meant: If an airplane is as safe as average then it has PUT_NUMBER chance of having 2 incidents after 150k flights. 0.01% is actually the number I'm getting, assuming parent estimates are correct and making naive assumptions. In other words only 1 every 10 000 airplane models will have 2 incidents that early on if they are of average safety.

That is different then stating the probability of it being as safe as the average airplane, which you can't do as easily without additional modelling/priors and bayesian statistics.

<comment><USER31> <addressing all comments>

Lies, damn lies, and statistics. The NH is that a plane has 1/10 [M * flights] failure rate. The odds of 2 failures in 20M flights falling in same (random) stride of 150K flights are 150K/20M = 0.75%.

[E: fixed numbers] [EE: yes, I admit this calculation is incorrect]

</comment></comment></comment></comment><comment><USER33> [https://twitter.com/ByMikeBaker/status/1105909327255080960](https://twitter.com/ByMikeBaker/status/1105909327255080960)

This is more revealing than they'd like, I think.

<comment><USER34> > In a statement, Boeing said it recommended to the Federal Aviation > Administration that the 737 Max be grounded "out of an abundance of caution > and in order to reassure the flying public of the aircraft's safety."

A company is recommending _to their regulator_ that the regulator take action _against_ them. That is a pretty solid indicator that the lawyers have a rough idea of potential liability and are now trying to mitigate damages.

<comment><USER35> A day after personally calling the president to ask him to prevent the regulator from taking action. This is just a bad attempt at saving face.

<comment><USER36> Since the grounding has affected search queries, could you help me with a citation?

<comment><USER37> [https://www.nytimes.com/2019/03/12/business/boeing-737-groun...](https://www.nytimes.com/2019/03/12/business/boeing-737-grounding- faa.html)

> Early Tuesday, Dennis A. Muilenburg, the chief executive of Boeing, spoke to > President Trump on the phone and made the case that the 737 Max planes > should not be grounded in the United States, according to two people briefed > on the conversation.

</comment></comment></comment></comment></comment><comment><USER38> What's the current status regarding analysis of the black box data recorder? The only source I've seen [0] states that Germany lacks the software to analyze it. "This is a new type of aircraft with a new black box, with new software. We can't do it," BFU spokesman Germout Freitag said.

[0] [https://www.dailysabah.com/africa/2019/03/13/ethiopia- cannot...](https://www.dailysabah.com/africa/2019/03/13/ethiopia-cannot-read- black-box-from-boeing-jet-crash-to-send-it-abroad)

</comment><comment><USER39> This shouldn't be Trump announcing the ban. Either FAA or Secretary of Transportation should be announcing the grounding of flights. Its just odd to me that Trump would be involved...

<comment><USER40> The President is analogous to the Chairman/CEO of [most of] the executive branch. That role can tell them what to do and what do focus on, but mostly doesn't. He told them what to do, now the FAA has to do it. The Secretary of Transportation could likely have unilaterally issued an order without needing it to tell the FAA what to do, or waiting for the President.

But either way, this is symbolic and shows the stance of the government to the world and internally. The highest office in the US is grounding the planes like the rest of the world is, the administrative nuances are irrelevant. Boeing and the airlines would be the ones to challenge it, way to go for PR.

<comment><USER39> Of course the President can just tell the FAA what to do. I understand that.

The question is how the public should have been informed by the event. Dan Elwell, the acting director of the FAA, is both a military and commercial pilot. If he made the announcement, it would have carried far more weight than Trump (who likely doesn't know much about airplanes).

<comment> Const-me > Trump (who likely doesn't know much about airplanes)

Trump owned an airline with a fleet of 17 Boeings. He also used 2 large Boeings as private jets.

Very likely he knows a thing or 2 about airplanes.

<comment><USER41> I own quite a nice spider plant.

Surprisingly, I am not a botanist.

<comment> Const-me You likely know about spider plants much more than average person who doesn't have any of them.

</comment></comment></comment></comment></comment></comment><comment><USER42> Does anyone have any idea WHY the US was the holdout here? I'm not well- versed, but my understanding is that aviation safety is generally very good, and that the US is not an outlier on the bad side. While grounding a plane at this point is premature from the stance of conclusion, it seems reasonable from the standpoint of excessive caution that seems to be the norm for the industry.

I can conjecture about Boeing being a big US manufacturer, etc, but is there any evidence at all for why the US held out on this one? My initial reaction was that there must be a good reason for the holdout, given our safety record, but on reading more about it, I've not seen one. (Again, relative to the stance of excessive caution).

<comment><USER43> Boeing and the FAA have a deal to let Boeing self regulate. In exchange they are supposed to tell the FAA of any internal issues. [1]

This of course is insane when you are talking about a for profit business.

[1] [https://youtu.be/vWxxtzBTxGU](https://youtu.be/vWxxtzBTxGU) 20min in.

<comment><USER14> It's a shame this is getting upvoted because it's an incomplete picture.

FAA Delegated Organizations

Page: [https://www.faa.gov/other_visit/aviation_industry/designees_...](https://www.faa.gov/other_visit/aviation_industry/designees_delegations/delegated_organizations/)

"Regular FAA oversight of an ODA is accomplished by a team of FAA engineers and inspectors to ensure the ODA holder functions properly and that any approvals or certificates issued meet FAA safety standards."

List of delegated organizations: [https://www.faa.gov/other_visit/aviation_industry/designees_...](https://www.faa.gov/other_visit/aviation_industry/designees_delegations/designee_types/media/ODADirectory.pdf)

Spoiler: there's a lot more than Boeing on there.

I don't know about the specific concerns in that video, just replying to the insinuation that Boeing has some strange deal that exempts their planes from oversight by the FAA. They don't.

</comment></comment></comment><comment><USER44> Maybe the F.A.A is a bit too cosy with Boeing?

<comment><USER45> Probably, but I'm guessing the problem lies elsewhere in this case.

[https://www.vox.com/policy-and- politics/2019/3/13/18263719/b...](https://www.vox.com/policy-and- politics/2019/3/13/18263719/boeing-ceo-dennis-muilenburg-trump-tweet-call)

[https://www.militarytimes.com/news/your- military/2019/03/13/...](https://www.militarytimes.com/news/your- military/2019/03/13/shanahan-faces-ig-complaint-over-boeing-ties/)

</comment></comment><comment><USER46> Also see @salawat above on nacelle lift-induced pitch instability. We now have airliners that begin to resemble the F-117 in their dependence on computers for controllability in flight.

<comment><USER47> There's nothing wrong with unstable airframes. Military craft have required computer assisted flight for decades.

What's problematic with 737 MAX is that the stability assist was obviously installed as an after thought, and even worse, it's dependent on instrumentation that does not have several layers of fault tolerance as would be the case if it was actually built with the care that planes actually require to be as dependable as they are.

So the instability is not a problem. That boeing tried to get around it with a cheap patch of jury rigged software that is depending on input from non-fault- safe instrumentation, is.

<comment><USER48> Inherent instability in a commercial aircraft seems like a very bad idea. Safety has to the top priority. The military has very different priorities.

<comment><USER49> And would that affect its capacity to glide?

<comment><USER50> Not in this case, since the instability is caused by the lift generated by the engines.

<comment><USER51> IIRC, the instability is caused by the engine nacelles (the metal shroud around the turbofan), and therefore is present whether the engines are active or not.

</comment></comment></comment></comment></comment></comment><comment><USER52> It was inevitable at this point. Sad that it had to happen due to the external pressure of _every other country in the world_ banning it first.

<comment><USER19> IT wasn't inevitable. There's nothing that's found to be unsafe about the aircraft. If anything it shows that airlines in other countries don't train their pilots properly. MCAS can be disabled by an easily visible switch directly in the cockpit and you can override it with manual trim control as well. The Lion aircraft that crashed before was having MCAS problems _FOUR_ flights repeatedly before the one that crashed. Third world aircraft maintenance combined with poor pilot training and non-idiot proof software made these disasters happen. It's not something that would happen in the US or any other first world country.

<comment><USER53> I'm sure you're willing to hop on a flight with one of these planes, but I'm not and I doubt the majority of people who've heard about it are. Canada saw the same sort of flight pattern dip in the new crash that happened to the old one. It's only that the FAA administrator is a lobbyist of the air manufacturing industry that they didn't follow suit.

<comment><USER54> Still, the flight might be a way safer than taking a ride in a car.

</comment></comment></comment></comment><comment><USER55> "Based on new information..."

What new information??? Or maybe "the taste of egg on our face?"

<comment><USER56> See this PDF: [https://www.faa.gov/news/updates/media/Emergency_Order.pdf](https://www.faa.gov/news/updates/media/Emergency_Order.pdf):

"On March 13, 2019, the investigation of ET302 crash developed new information from the wreckage concerning the aircraft's configuration just after takeoff that, taken together with new ly refined data from satellite-based tracking of the aircraft's flight path, indicates some similarities between the ET302 and JT610 accidents that warrant further investigation of the possibility of a shared cause for the two incidents that needs to be better understood and addressed"

</comment></comment><comment><USER57> All of this news has prompted me to see where Boeing stock is at. Beyond the expected decline in price, I was more interested to find out how parabolic BA's price rise has been in the last 5 years.

Side note: I tried finding a site that would let me link out to a chart showing the full price history of BA. It's surprisingly difficult to find.

<comment><USER58> Basically they bet right on where the future of commercial aviation is going: more direct flights rather than hub-and-spoke connections, smaller jets that the airlines can fill completely, fuel efficiency is critical, and the air travel industry as a whole would recover after a pretty miserable first decade of the millenia. Their main competitor, Airbus, bet wrong, investing heavily in the A380 which hasn't found much of a market. That's been reflected in their profits lately: 787 and 777 sales have been quite robust, while A330/A350/A380 orders have been anemic.

<comment><USER57> Good insight, thank you!

</comment></comment></comment><comment><USER59> In this list of 737 accidents, correct me if I'm wrong, seems that the crashes for similar reasons (shortly after takeoff) are 3 , not 2. There is other one (May 18, 2018 ) involving a 737-100/200 that seems strictly related to the other two by time and dynamic: [https://en.wikipedia.org/wiki/List_of_accidents_and_incident...](https://en.wikipedia.org/wiki/List_of_accidents_and_incidents_involving_the_Boeing_737)

<comment><USER60> The 737-200 that crashed was a 40-year-old airframe, and the crash characteristics are only similar in that they all occurred shortly after takeoff.

The 737-MAX-8 crashes occurred within 6 months of each other, both on a brand new airframe on a new aircraft with a new control and sensor system that produced VERY similar profiles in rapid climbs and descents that point to an issue with said new autopilot.

The MAX-8 and the 200 are VERY different aircraft, even if they're fundamentally built around an original ancestor.

</comment></comment><comment><USER61> Is this a buying opportunity for Boeing stock?

NYSE: BA $373.96

Seems to be 'discounted'.

<comment><USER62> Never catch a falling knife.

Source: Career spent as a Wall Street Trader

<comment><USER37> You can pick one up off the floor, though.

There's every reason to believe a) Boeing will take a hit for this and b) Boeing will _not_ go out of business because of this.

<comment><USER63> Yeah, but whether the hit is permanent or long lasting is still up in the air (unlike the 737 Max 8). On the one hand this could just turn out to be a coincidence or an easily fixed issue and Boeing's stock will rebound quickly. Or it could mean a massive recall of this model which will hurt Boeing for years to come. The current price is a reflection of this uncertainty and it could go either way.

<comment><USER64> It wouldn't surpise me if this were the final nail that shifted global orders toward the A320 Neo. Boeing has been putting lipstick on a pig with the 737 for 20 years now and people know it. They've only held out so long on their reputation at this point, and now that's in the gutter. The A320 Neo is an all around better, more modern aircraft built with computerized systems in mind from the ground up.

<comment><USER65> > The A320 Neo is an all around better, more modern aircraft built with > computerized systems in mind from the ground up.

Isn't the A320neo _also_ new engine lipstick on a 30 year old airframe?

<comment><USER66> The 737 was a 30 year old airframe 20 years ago. Boeing was really trying to sneak past regulators on this one - reading pilot forums, people are also complaining about avionics updates that they didn't get any re-training for either.

</comment></comment></comment></comment></comment></comment></comment><comment><USER67> It sounds like what you really need are flawless automated systems because humans will not always be able to compensate if the system errors are serious enough. And in this case they tacked on a kludgey flight control subsystem without adequate testing to see how it impacted the overall flight control, and did not bother telling the pilots. The executives probably did this to save money even though engineering told them it was unethical.

</comment><comment><USER68> I'm curious to know how much civil disobedience there's been at airports once passengers realized they'd be flying a 737 MAX. With well over 100 people on a typical flight, and it only taking one dissenter to cause a disturbance that can ripple out to many more passengers, it may have been untenable to continue flying these anyway.

<comment><USER69> > civil disobedience

What do you mean civil disobedience? It's not like there is a law forcing you to board the plane if you don't want to.

<comment><USER70> Sure, but you won't get a refund for your ticket or your time. And some people might feel compelled to alert their fellow passengers if they felt the airline was planning to put them on a plane they felt was unsafe. These things could lead to anger, hence civil disobedience.

<comment><USER28> My experience has been airlines will rebook you if you have legitimate safety fears.

</comment></comment></comment></comment><comment><USER71> Honestly, this is tantamount to negligence by the FAA. This plane should've been grounded immediately and all of them checked for maximum safety. But the US, as dumb as always, just goes "nothing to see here", "we're waiting for data despite the data being 2 crashes where everyone died in 5 months".

<comment><USER72> What "checks?" They've already been checked for maximum safety and US and Canadian pilots aren't crashing in them.

<comment><USER71> So if over 200 people die on your watch in a statistically unlikely event, you're not going to re-check the planes? What makes US and Canadian pilots anymore worse than Indonesian and Ethiopian pilots? In the Indonesian case, it was a known software fault.

</comment></comment></comment><comment><USER73> I asked yesterday on Aviation stackexchange [https://aviation.stackexchange.com/q/61069/11524](https://aviation.stackexchange.com/q/61069/11524) whether the EASA and the FAA has disagreed on the airworthiness of a plane before. I doubt they did.

<comment><USER74> At least there is a new statement from FAA, different from the one you link to in there:

[https://pbs.twimg.com/media/D1j5YuBXQAATWlk.jpg](https://pbs.twimg.com/media/D1j5YuBXQAATWlk.jpg)

"March 13, 2019 | 3:00 p.m. ET

STATEMENT FROM THE FAA ON ETHIOPIAN AIRLINES

The FAA is ordering the temporary grounding of Boeing 737 MAX aircraft operated by U.S. airlines or in U.S. territory. _The agency made this decision as a result of the data gathering process and new evidence collected at the site and analyzed today. This evidence, together with newly refined satellite data available to FAA this morning, led to this decision._ The grounding will remain in effect pending further investigation, including examination of information from the aircraft's flight data recorders and cockpit voice recorders. An FAA team is in Ethiopia assisting the NTSB as parties to the investigation of the Flight 302 accident. The agency will continue to investigate"

Their previous one, less than 24 hours ago, had: "Thus far, our review shows no systemic performance issues and provides no basis to order grounding the aircraft. Nor have other civil aviation authorities provided data to us that would warrant action."

</comment></comment><comment><USER75> And Boeing recommended it, which was (finally) the smart move on their part. It's the only way to regain the public's confidence. If one more 737 Max had fallen out of the sky, it would have meant the end of the company. At least this way, Boeing is getting out in front of the problem. Better late than never.

</comment><comment><USER76> Right move finally. Like I said in the post about Canada, at this point it's even better for Boeing. No one in the US wants to fly in this plane so it's better for Boeing if it's grounded.

</comment><comment><USER77> I studied aircraft UX as my dissertation work. I'll admit it is a few years out of date, but unlike JavaScript libraries, aircraft don't change that fast.

Here's my understanding/analysis of the situation: 1\. Boeing was under pressure to create a more fuel-efficient version of the 737NG to compete with Airbus's A320neo. The 737MAX was the result. 2\. In order to be lower investment for airlines, it was critical that the 737MAX share a type rating with the 737NG. This meant that a pilot certified ("checked out") on an NG would be able to fly on the MAX without further certification. 3\. To gain fuel efficiency, the MAX has larger engines. To first order, larger engines result in more efficiency: by accelerating _more_ air by a smaller amount you leave less energy in the air that's exiting the aircraft. The larger and more efficient engines results in 14% less fuel burn. That's a major improvement! 4\. The larger engines and their placement resulted in a "pitch-up moment" during certain flight regimes. What this means is that when you add a lot of power to climb, and/or during steep turns. 5\. To compensate and – this is critical – to maintain the same type certification, Boeing added something called MCAS (Maneuvering Characteristics Augmentation) which nudged the nose down by trimming the stabilizer (the horizontal bit of the tail) down (which pushes the tail down and therefore the nose up). It appears to be activated without pilot input. 6\. There are other mechanisms which also "trim the stab down" and there has always been a mechanism which disconnects them: pulling back hard on the yoke. This is a natural motion for pilots because in all flight regimes pulling back on the yoke pulls the nose up, which is what you want to if the nose is going down. There is a backup mechanism as well which involves flipping a pair of cutout switches and manually taking over. 7\. My speculation is that because MCAS was considered critical to making the MAX fly "like" the NG, the first disconnect mechanism was removed on the MAX. This is critical bit #2: the obvious/intuitive mechanism to disable something pushing the nose down was removed. 8\. Because MCAS was so important, two (?) Angle of Attack sensors were added to the MAX. These sensors appear to fail more often than they should. In aviation terms that might mean they work 99.99% of the time, not 99.999%. 9\. So now you have a situation where an aircraft has a required mechanism to fly/feel like another aircraft in order to maintain a consistent type rating but which is reliant on a shaky sensor. And when the sensor fails, the mechanism has – purposefully – been made more difficult to disconnect. From what I can tell, this entire set of decisions was driven by this type certificate/rating decision. That's the key mistake. I understand why this was done from a business standpoint, but if you're going to rely on manipulating flight characteristics it had better be bulletproof. Note that I'm not against the philosophy: Airbus has been doing it successfully for 25 years starting with the A320. But this isn't bulletproof. As it stands today, I wouldn't fly on the aircraft. Pilots are following this stuff pretty closely and are incredibly well-trained, but in a high pressure, low altitude, high wingload, high AoA situation, having them fiddle around looking for switches is a huge mistake. I have never said this about an aircraft before. I expect Boeing to re-enable the yoke disconnect and for the FAA to require recertification and a new type certificate for pilots to fly the MAX. Unfortunately, for Boeing, this will make them far, far less enticing to buy.

<comment><USER25> >To compensate and – this is critical – to maintain the same type certification, Boeing added something called MCAS (Maneuvering Characteristics Augmentation) which nudged the nose down by trimming the stabilizer (the horizontal bit of the tail) down (which pushes the tail down and therefore the nose up).

You reversed that.

MCAS is designed to force the nose down (that part is right) to counteract an upward pitching moment. That requires the leading edge of the horizontal plane to trim upwards, increasing lift at the tail, which pitches the craft's nose downward.

I think.

</comment></comment><comment><USER78> I'm guessing that Southwest didn't have these. They seem to get everything important right.

Edit: I was dead wrong. They had more 737 Max 8's than any other airline in the US.

<comment><USER79> Southwest has more 737max than anyone else. However they have outfitted it with an optional avionics package that includes a HUD, an additional AoA sensor and indicator in the HUD and PFD, and an "AoA disagree" indicator light. ([https://theaircurrent.com/aviation-safety/southwest- airlines...](https://theaircurrent.com/aviation-safety/southwest-airlines-is- adding-new-angle-of-attack-indicators-to-its-737-max-fleet/))

They also train their pilots using a 737max specific curriculum.

<comment><USER80> Why was a safety critical system (which was really only needed to place a bandied on retrofitting bigger motors on an older frame design) being sold as an "optional package". You need at least 3 redundant sensors in any safety critical system. This is just basic rocket science. Boeing and the FAA are negligent and should not be trusted.

<comment><USER81> « You need at least 3 redundant sensors in any safety critical system «

Huh? Says who?

<comment><USER82> You need at least three in any system that can deliver conflicting data so that if one faults then the other two can 'out vote' the faulty one.

That allows the system to have at least one failure and still operate.

With just two sensors any fault is an unidentifiable failure - how does the system know which is correct when there are just two votes?

It may be there's a third input from some other sensort, but then technically we're back to at least 3 sensors voting on the issue.

<comment><USER75> It's an AoA sensor. Planes flew without AoA sensors for 100 years; it's a _useful_ sensor but not a _critical_ sensor. Pilots and autopilots are perfectly capable of flying planes without it. If two AoA sensors disagree, you just stop making decisions based on the AoA sensor and fly the plane without it.

<comment><USER30> The crux of the problem is that the NG/MAX isn't certified to fly with malfunctioning alpha vanes. On the NG and MAX the effort required to move the control column varies based on the angle-of-attack (a.k.a. elevator feel system). On the MAX the airspeed calculation is influenced by the AoA and MCAS is triggered by data from a single alpha vane with no sanity checking.

Functioning alpha vanes are critical on the MAX and NG.

<comment><USER75> That's the huge design flaw. They should have made the AoA sensors either critical and triply redundant, or not critical at all (as is typical).

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER83> Maybe FAA should be grounded too, it's obvious to have the plane grounded based on the public data and patterns. Why does it take longer than that to make a decision.

</comment><comment><USER84> It feels like there is an online service business idea in here somewhere. Some sort of way to verify the items that impact your life every day are safe and updated.

</comment><comment><USER85> Does Boeing have the ability to disable the subsystem in the 737 Maxes that is the issue? (I'm not saying that this would be an alternative just curious .)

<comment><USER86> Probably, but from everything I've read to date on the issue, the feature is a safety requirement due to the increased possibility of nose lift during takeoff, which might create a stall.

So, 'just disable the trim' that has been throw around really sounds like they're disabling a critical feature, safety-wise, and while it's possible to fly the plane successfully without it, someone somewhere determined it was less-safe to do so.

</comment></comment><comment><USER87> Is this somehow related to the recent articles on historic problems with rudder design in the 737?

</comment><comment><USER88> Its a shame that the airplane safety streak we were one has been so firmly and decisively ended.

</comment><comment><AUTHOR> I wonder if this will create a "land rush" situation in the aircraft leasing market.

Maybe not given that only 130 737-Max aircraft have been delivered to airlines.

Does anyone here know how aircraft leasing works in scenario like this? e.g. grounding of an aircraft model for an unknown duration, do airlines have the option so "switch out" currently leased aircraft?

<comment><USER89> 350+ 737MAX have been delivered

</comment></comment><comment><USER90> I have to fly soon. Do yu suppose prices will go up, or are there enough planes to go around?

</comment><comment><USER91> I thought that was up to the FAA, but maybe it is an executive order.

<comment><USER92> Perhaps this will be the point at which the current state of the FAA comes under scrutiny and review.

In the UK the equivalent CAA is half-jokingly called "Campaign Against Aviation" for its merciless regulation.

The FAA seems to have veered in the opposite direction, inviting manufacturer staff to lead certification processes etc

</comment></comment><comment><USER93> Good move but wish they did it sooner compared to other countries.

</comment><comment><USER94> Boeing 737 Max 8 has a different software system. That software is now a focus of investigators. The Max 8 is outfitted with bigger, more fuel-efficient engines than earlier 737s, and the weight and positioning of those engines shifted the plane's center of gravity forward, increased the potential for the nose to pitch up after take-off. To counteract this risk, Boeing developed software known as the Maneuvering Characteristics Augmentation System, or MCAS.

Max 8s come equipped with a sensor that reads the plane's angle relative to the wind flow, prompting MCAS to automatically trigger the plane's nose to angle downward if it gets a specific reading.

However, problems could arise if the MCAS system gets erroneous sensor readings. The system automatically pushes the plane's nose down, potentially surprising pilots who are unfamiliar with the system and overriding their commands.This is what investigators believe happened to Lion Air Flight 610 before it crashed in October

more details [https://www.cbsnews.com/news/boeing-737-max-8-boeing-737-800...](https://www.cbsnews.com/news/boeing-737-max-8-boeing-737-800-how- are-the-planes-different/)

<comment><USER95> >The Max 8 is outfitted with bigger, more fuel-efficient engines than earlier 737s, and the weight and positioning of those engines shifted the plane's center of gravity forward, increased the potential for the nose to pitch up after take-off.

Umm, a little confused here, if the center of gravity shifted forward, why will the pitch up tendency increase?

<comment><USER64> >Umm, a little confused here, if the center of gravity shifted forward, why will the pitch up tendency increase?

Because the center of thrust is also moved forward, and its effect is much greater than that offset by the center of mass. The 737 airframe was never designed to handle such powerful engines.

<comment><USER96> The center of thrust moving forward would not have any effect on the pitching moment.

<comment><USER64> >The center of thrust moving forward would not have any effect on the pitching moment.

Sure it would. Here's a better explanation than I care to make: [https://www.quora.com/Where-should-the-center-of-mass- lift-a...](https://www.quora.com/Where-should-the-center-of-mass-lift-and- thrust-be-on-a-jet)

"If the Center of Thrust does not act through the Center of Gravity there will be a moment causing the aircraft to pitch, yaw or roll about the axes of the aircraft and the moment(s) must be counter balanced by design (including provision for trimming when the thrust is varied)."

Boeing chose to counteract that newly induced pitch moment with software, so that they could sell the MAX 8 to airlines as not requiring any new training or type ratings. And now nearly 400 people are dead because of a marketing decision.

<comment><USER96> If you move an engine forwards (or backwards) you are moving it along its thrust vector. Therefore the moment resulting from the distance between the thrust vector and the center of mass is unchanged.

Source: Physics 101

<comment><USER97> Right, but if you increase the _power_ , you increase the moment.

</comment></comment></comment></comment></comment></comment></comment><comment><USER98> Reading one of the pictographs in the article, it's noting that the heavier engines changed the aerodynamics of the plane in a negative way. Boeing engineers added what they call MCAS to counter these negative effects.

Now, I'm not an aerospace engineer, but common sense tells me that if you add something to a system that introduces a negative effect, you remove that something - not add something else to counter it.

But, that's me.

<comment><USER99> That's kind of a simplistic view, isn't it? By that logic you should remove the pilots, crew and passengers since they add a negative effect (weight) to the plane.

<comment><USER97> In medical instruments, we preferred to _eliminate_ a failure mode rather than _mitigate_ it (when possible). That's not the same as saying "just don't build the device".

<comment><USER99> Preferred how strongly? Eliminating the failure mode in this case means designing a whole new wing from scratch, which is nearly the same amount of work as designing a whole new plane from scratch. So Boeing's alternatives (while maintaining the same efficiency) were to completely replace the 737, or fix the issue in software. The latter option is obviously vastly less expensive. If you're confidence in the software fix is high, it's probably a reasonably choice. _In hindsight_ Boeing's confidence may have been misplaced.

</comment></comment></comment></comment><comment><USER100> Let's be clear about what is happening here. This is simply a 'not on my watch' and 'CYA' philosophy that is what society has become today with so many news hungry sources and social media. Anyone in a position of power is so worried about getting blamed by irrational people for a bad outcome that they will simply make a choice to prevent that from happening at any cost. This doesn't mean that it's the wrong choice. But the fact is all anyone has to think is 'wow if this happens a third time I will get blamed'. [1] The old 'abundance of caution'.

The fact is at what point do you do this? What about an extreme. Like every time there is any crash just ground every single plane until the extensive investigation is done?

[1] And it should be irrelevant what has happened in other countries as far as grounding as well. Assumes they have concluded something and have more facts which of course they don't.

Edit: I love when people who comment on HN based on what they read feel that they know more about the actual risk than the people (per my reply to a comment) at Boeing.

<comment><USER101> I don't feel this way at all. The more we learn, the more it seems like Boeing misrepresented the extent of the changes they made inbetween the 737 and 737MAX8/9 models in order to avoid recertification, then undereducated the pilots about those changes.

As a consumer who has flown on these plans many times, I'm glad they have been grounded until a fix can be deployed.

<comment><USER100> > The more we learn, the more it seems like Boeing misrepresented the extent > of the changes

Based on what? News stories that have come out? Is that the highly accurate source?

<comment><USER102> Based on the physical fact that the engines are different, mounted in a different place, and generate different thrust vectors.

<comment><USER103> Engines are also very different between 737 Original and Classic, so having different thrust vectors between generations is not happening for the first time.

<comment><USER100> And exactly my point. The parent comment stated a fact that could be true or not be true. And it's almost certainly something they read and therefore interpreted as significant an important fact. And that was what I was saying. All the info you read regardless of whether it is quoting an expert or not [1] comes 2nd hand and with nominal validity vs. people at Boeing being in a position (by the fact they employ and have access to actual experts) much better able to assess the danger. Of course I don't know if what you are saying is correct but that doesn't matter for the point I am making but thanks for making it just the same!

[1] Which assumes the expert is even being quoted correctly which as anyone knows is not always the case.

</comment></comment></comment></comment></comment></comment><comment><USER91> Assuring to see that Trump has more sense than the FAA and Boeing, although he is a bit late to the party.

</comment><comment><USER104> I find it scary that Trump had to issue an Executive Order to get this to happen. It tells me that the FAA no longer cares about safety, but is more interested in corporate interests over the lives of 180+ people at any given time.

</comment><comment> shaki-dora Welcome to the end of the thought process.

<comment><USER105> Could you please stop posting unsubstantive comments to Hacker News?

</comment></comment><comment><USER106> Since this was Trump who issued the grounding order, can we finally dismiss all the previous HN comments of people saying the FAA and Trump are in cahoots to keep 737 Max 8's flying in the US to prop up Boeing.

\-- Edit -- Apparently not. Now all the comments are blaming the FAA and saying it is fishy it took an executive order.

<comment><USER107> I think it's the lack of information that's scaring people. We don't know why the Ethiopian flight went down, it's just really suspicious that 2 brand new airplanes crashed catastrophically so soon after delivery.

I think it's a good move until we know the full picture though. Better to err on the side of caution when lives could be at stake.

<comment><USER108> Everyone seems to be zeroed in on MCAS. Completely unknown at this time whether that system was related to the Ethopian crash. What the two crashes do have in common other than the aircraft model is a third world carrier, dubious pilot qualifications, and heavy reliance on automation. But it's somehow not OK to talk about that.

<comment><USER25> Ethiopian Captain had over 8000 hours, and the airline is a Category(right word?) 1 Airline, able to fly into and out of the U.S. directly. They actually have a stellar safety record.

Just because it's Africa doesn't mean the operators were lacking.

</comment></comment></comment></comment><comment><USER109> (Guessing upon all available information) It seems that something is wrong when the auto-pilot is turned on... And this seems to happen a few minutes after the take off...

<comment><USER110> Official rulings aren't in yet, so this is all wild speculation, but the dominant hypothesis appears to be that these new planes are equipped with MCAS ("Maneuvering Characteristics Augmentation System") software that is supposed to account for inherent aerodynamic instability in the design by making it much harder for the pilot to accidentally crash the plane.

Without going into too much detail: there are many tradeoffs in airframe design, but one of them is fuel efficiency vs. inherent stability. Some airframe designs eke out a bit more miles-per-gallon at the cost of having ranges of motion where if the pilot gets the plane into that state, the feedback loops on motion become positive and the plane is likely to tip over, stall out, spin, etc. Boeing's Max-8 design makes this tradeoff, and the MCAS system is supposed to help compensate for this design by forcing the pilot to nose the plane down (to improve airflow over the wings and generate more lift) if the plane is pitched too high.

Problem might be that MCAS can malfunction and think the plane is pitching up when it's not, and if the pilot can't figure out how to disable it, they get very confusing signals--- _they 're_ pulling back on the stick to get the plane to climb, but MCAS is pushing the stick _forward_ to avoid an expected stall that a malfunctioning sensor is telling it will happen. End result: pilot and the computer fight each other while the very important business of "keeping the plane in the air" isn't done and the plane crashes.

<comment><USER111> It sounds to me not just a software issue but a systems issue where software, hardware and architecture play a role. What used to be a sensor to measure the angle of attack became suddenly key input, single source in a short term control loop for the most vital axis. What could go wrong...

Taking into account the other sensor data is an obvious choice. A better understanding the quality of the sensor data in real field operation may also be required. Clearer stabilization problem indication, quicker manual disengage of auto pilot (several reports of nose down events) and MCAS are others. Decreasing the allowed tail trim for MCAS is another.

Then that leaves: Another one or two sensors. Independent review of the engine control laws (report of unexpected low thrust when climbing).

There is a lot to be done. The plane was rolled out too early and fixing the cut corners for real could take a while.

</comment></comment></comment><comment><USER112> It wasn't _inevitable_ ; if it happened solely because Trump made them do it (edit: the article now seems to contradict this, but did not when I wrote the comment) it's truly a red-letter day for rationality and evidence-based reasoning.

The conversation around this subject has degraded to irrational hysteria, but really: do you think Trump knows anything about airline safety? Is this really how we want the system to work?

Today it's an airplane model, but tomorrow it's banning travel from Africa because of an emerging disease, or capitulating to anti-vaxxers because of a news story.

<comment><USER113> I mean.. the guy did own and operate an airline at one point. So it's a little silly to say he knows _nothing_ about it, no matter how much you don't like the guy.

<comment><USER114> I mean, he also claimed that newer airplanes are less safe than older airplanes. Which seems pretty absurd given that crashes have been trending down for sometime.

[https://theweek.com/speedreads/828609/trump-claims-old- simpl...](https://theweek.com/speedreads/828609/trump-claims-old-simpler- airplanes-safer-such-planes-actually-crashed-more-often)

</comment></comment></comment><comment><USER53> That it took the president to do this is a pretty awful condemnation of the FAA. Maybe he shouldn't have appointed an industry lobbyist to the position in the first place.

</comment><comment><USER115> The whole software is made in India and now is said having major software flaws. This is not the first time.

The rest engineers in Boeing, many are not longer first class, they got their jobs because of race and gender.

Your future heart doctor might be from the best medical school, but they might get in either by bribery or worse, by AA(affirmative action), they're not really up to the job, and they may kill you with good intentions without you knowing it.

Let the merited-based engineers do the most critical designs in this country please, people actually are different. For those who thinks everything should be absolutely equal, while that thought make you high whenever you think about it, you and many others may get killed by that ideology.

</comment><comment> tuna-piano The reactions of Boeing (and potentially the FAA) deserve much more criticism than the actual mistakes which led to the crashes. Accidental mistakes/oversights are expected and can be forgiven. Thoughtful responses which seem to have attempted to put profit above moral standards cannot be forgiven.

Many other thoughts...

-People, including executives, seem to have a very hard time thinking big picture. Q4 2018 financial results seem so important only in the time period around Q4 2018. History doesn't care about Q4 2018. History will care about the crashes (especially the second, more preventable one which happened while Boeing was working on software fixes "to make a safe plane safer")

-Overall, it is bizarre living through and watching these two crashes and the reactions to them in real time. I've often watched episodes of air crash investigation shows, the most interesting being series of crashes of the same aircraft models from decades ago (before I was in adulthood).

-No doubt that Boeing will be viewed negatively in historical light. Their culpability was sealed with their reaction to Lion Air, and only further worsened with their reaction to Ethiopian.

-I think the worst possible outcome for Boeing will be if it is determined that the MCAS issue is nonrecoverable even with the instructions that Boeing has repeated.

Still curious... what made the FAA and Boeing switch sides on this issue?

1\. Was there new information? (Satellite data, etc)? -or-

2\. In the inevitability of a ban, is it just a better look to seem "proactive" than to go down kicking and screaming?

<comment><USER116> It sounds a lot like Trump overrode the FAA, more than the FAA changing its mind.

<comment> tuna-piano Boeing did definitely switch sides though: [https://twitter.com/ByMikeBaker/status/1105909327255080960](https://twitter.com/ByMikeBaker/status/1105909327255080960)

</comment></comment></comment><comment><USER86> I think we should also lay some blame on the airlines as well. Why should they have accepted such planes in the first place? Don't they have their own engineers and safety inspectors to counter-balance a plane company's marketing department?

More so, I hope there are subpoenas of Boeing's internal communications regarding this matter. Rumors I have read elsewhere indicate some real skullduggery if true.

Lastly, it really calls for the need of independent software auditing and compliance. There should be no proprietary software operating in regulated airspace.

<comment><USER117> > There should be no proprietary software operating in regulated airspace.

Lmao seriously??

<comment><USER118> Yes, the entire flight control system could just be an Electron app running open source javascript. Or typescript if you're a (type) safety nut.

# npm install boeing-aileron boeing-throttle boeing-flight-controls

<comment><USER119> Trust me, somebody somewhere have said that unironically...</comment></comment></comment></comment>


Web Sockets specification (IETF Internet Draft) - <AUTHOR> http://tools.ietf.org/html/draft-hixie-thewebsocketprotocol-54

<comment><USER2> The C for RFC in short - What's the point ?

I really don't understand what problem this draft solves, and the draft doesn't seem to explain it coherently.

It effectively describes just another layer on top of TCP that implements its own addressing, loosely follows HTTP syntax and utilizes TLS for security. The application still needs to implement yet another layer to deal with the data carried by this protocol. So instead of using (TLS + application protocol) combo, the app needs to use (TLS + WS + application protocol).

So what's the point in making this protocol a standard ?

\-- PS --

 _Historically, creating an instant messenger chat client as a Web application has required an abuse of HTTP to poll the server for updates while sending upstream notifications as distinct HTTP calls._

Perhaps that's how they do it at Google, but _historically_ applications like httptunnel simply opened exactly two persistent HTTP connections - one with a very long POST and the other one with a very long GET - and used them to send data up and down respectively.

<comment><USER3> The point is, roughly, making a protocol for browsers to communicate bi- directionally with servers (that is, either side can send data to the other at any time; this spec tries to provide semantics of a TCP socket), which (a) gets through proxies and firewalls, (b) has as little overhead as possible, and (c) has no potential security vulnerabilities not already present in other types of browser connections (XHR, etc.).

Currently, the set of techniques collectively called "Comet" are inconsistent across browsers, fragile to new browser version changes, and extremely hacky.

> _The application still needs to implement yet another layer to deal with the > data_

Well sure, the application needs to implement the semantics of whatever the particular network app is that will communicate with a method like this. But that's always been true for any application. Something like this just tries to give web applications some of the same flexibility that applications with more access to the OS, and which could therefore just open TCP sockets, always had.</comment></comment>


What People Like About the Plan 9 OS - <AUTHOR> http://www.plan9.bell-labs.com/wiki/plan9/what_do_people_like_about_plan_9/index.html

<comment><USER2> I was fascinated with Plan 9. It just has really cool ideas in its design.

It has been said before and I agree. The problem with Plan 9 adoption isn't Plan 9. Plan 9 is beautiful. The problem is that Linux is quite alright as well.

Also, Linux has drivers for more hardware when Plan 9 was ready to be played with. Plan 9 doesn't. It is a chicken and egg problem. I remember trying Plan 9 and it just didn't have drivers for some of my hardware. It was like Linux in back in the days.

<comment><USER3> I'm amazed that "drivers" are still a consideration in OS design anywhere other than embedded systems. Why aren't we writing our operating systems to target hardware-abstracting hypervisors yet? Isn't that an obvious separation of concerns?

<comment><USER4> Isn't the BIOS supposed to be the hardware abstracting layer we run our programs directly on? That doesn't work any more (because BIOS is a legacy mess), so now we have kernels that act as the hardware abstraction, and write operating systems on top of those. Of course, now you need to target you operating system to a kernel.

<comment><USER3> Yes, the BIOS is exactly what's supposed to be doing the hardware abstraction, such that jobs like "read a block from a block device" are done via _hardware interrupts_ , not system calls. I think hypercalls are a good compromise, these days; what is a hypervisor but a BIOS running on the CPU?

There are already specialty OSes that take this tack--things like Openmirage ([http://www.openmirage.org/](http://www.openmirage.org/)) and Erlang on Xen ([http://erlangonxen.org/](http://erlangonxen.org/)). It could be done with a general-purpose OS just as easily.

<comment><USER5> The BIOS provides the programmer with basic I/O routines, but let's say performance wise it's far from being very efficient... And access from protected mode is quite tricky (but possible if you don't care about performance, security and reliability, but FreeBSD does it routinely to guess supported video modes from the graphic card).

When I read you, you seem to believe that writing to a disk (for example), is just a matter of having a "driver". That might be possible in a world where caching doesn't exist and where you don't have to support shitload of devices that claim to be a disk but really aren't or other drivers trying to pretend that they are a disk or other drivers trying to catch your writes to the disk, but really, you don't need an os I guess, just something minimal with hypercalls?

Tell me then, just as a thought experiment, if you get a kernel panic, what do you tell to the disk controller? Not today?

A snarky comment, I know, but I happen to be a kernel programmer and reading your comment was really annoying.

<comment><USER3> I'm assuming a full hypervisor, like Xen, which is basically a full-blown kernel that does its own resource pooling and abstraction. A "disk" for Xen is just like a "disk" for Linux--something that presents a disk-like interface in its driver and nothing more.

Let me rephrase my previous idea. You have _two_ kernels. One is an exokernel/library kernel, responsible only for managing the hardware[1]. It only does things when it's called into. The other is a "userspace" kernel, that does the virtual memory, process/thread management, etc. It's the one that registers interrupt vectors.

You could do this to Linux, today. Rip all the stuff that starts the machine and initializes the devices and abstracts them out, away from all the stuff that touches userspace, and put an known ABI between them. Then, take advantage of modern processors' specific support for hypervisors to make this ABI more performant.

The important idea is not that "somebody else" deals with the "drivers and stuff", leaving you free to write "just" an OS. Both the driver part and the process part can be considered part of one OS, and you can't have just one or the other, and likely the same vendor will be worrying about both. No, the important part is that each is a _layer_ , which should be able to treat the other layer as a black box with a known interface. In exactly the same way that TCP doesn't care whether it's being carried by IP or NetBEUI, while IP doesn't care whether it's carrying TCP or UDP, moving the driver part of a kernel out into a hypervisor means that the process-management part doesn't have to care what hardware-management part it's talking to, and vice versa. An "OS stack", to match your "network stack."

Really, we already _have_ "OS stacks" in a sense -- that's when we run a full- blown Linux kernel, running an (optionally paravirtualized) IA32/64 emulator, running another full-blown Linux kernel, running your software. This just eliminates everything redundant about that configuration, while keeping all the advantages.

\---

[1] Notably, this also means that the outer kernel is responsible for _permissions_ to the hardware. This means that each "inner kernel" running on this hardware only gets a single effective permission-set; if the one process on the inner kernel has access to a resource (a disk, say), then _every_ process on the inner kernel has access to that resource, because the inner kernel doesn't deal with the hypercall--it goes directly to the hypervisor.

This would have been a terribly big deal 10 years ago. Now? Who runs things as more than one mutually-untrustworthy user within the same virtual machine any more? Today, if you want separate security contexts, you use containerization. Which is to say, you get the hypervisor, not the OS, to enforce resource permissions.

<comment><USER5> Windows has got a Hardware Abstraction Layer: [http://en.wikipedia.org/wiki/Hardware_abstraction#Microsoft_...](http://en.wikipedia.org/wiki/Hardware_abstraction#Microsoft_Windows)

Until Windows 4, even the graphic part wasn't in the kernel, eventually they had to compromise for performance reasons.

I don't know Linux well enough to answer your question about Linux, but I'm pretty sure that concerns are well separated, however they are so fundamental to what the OS does that you can't just rely on some "external library".

An Hypervisor doesn't touch any hardware stuff. Basically if you consider kernel mode to run in ring 0 and user mode to run in ring 3, the Hypervisor runs in ring -1 and just deals with privileges to sum up. At to no instance does the hypervisor deal with the hardware such as disks or network cards. That code lies in the ring 0 kernel. All the Hypervisor says is ... "yeah ok, ring -1 kernel, you can play in that sandbox".

For example when you run a VM, the VM emulates hardware but the OS running in the VM stills need drivers...

Now it's not that easy to separate the OS from the drivers, because each OS has got some ideas about how the cache should work and how disks should be managed and what is actually a NIC.

When you write an OS you make your best so that writing a driver can be done to someone else and the code can be reused (e.g. for writing to multiple OS) but you CAN'T expect to use a common framework because well, at some point you will want to do DMA and you don't want to tell your user that their Intel SSD will run at 10 MiB/s.

<comment><USER6> Windows 4 != NT4

</comment></comment></comment></comment></comment></comment></comment></comment><comment><AUTHOR> There are Amazon AMI's for plan 9, called plan9-fossil. You don't use ssh to get in though. You need to use the plan 9 "cpu" command, using the "ec2" user and a random password printed on the instance console/system log. I have a plan 9 host running under VirtualBox that I used to access my Amazon Plan 9 host. It worked just great. Another little item is you have to allow TCP access to ports 17010 and 17013 on the instance.

<comment><USER7> Are there any ports of the `cpu` command for other operating systems?

<comment><AUTHOR> Use drawterm. It is a X11 application that allows you to connect to a remote Plan 9 server.

<comment><AUTHOR> Here's the command line I used:

drawterm -c 188.8.131.52 -u ec2 &

Note that I put it in the background. You will want to adjust your server address as appropriate.

I should add that drawterm just opens a blank Plan 9 desktop after you authenticate. You have to open a new command session on your own. A right click brings up a menu, you want to choose "new". This will turn the pointer to a "+" shape. You then right click and hold, stretching out the command window until it's the right size. When you release the right click, you will have a rc shell to type commands into.

<comment><USER7> Neat! Thanks for the instructions - that's definitely the easiest way to play around with Plan9 that I've come across (but I guess I haven't been looking too hard...)

</comment></comment></comment></comment></comment><comment><USER8> [http://www.plan9.bell- labs.com/wiki/plan9/what_do_people_lik...](http://www.plan9.bell- labs.com/wiki/plan9/what_do_people_like_about_plan_9/index.html)

[http://plan9.bell-labs.com/wiki/plan9/faq](http://plan9.bell- labs.com/wiki/plan9/faq)

[http://plan9.bell-labs.com/wiki/plan9/](http://plan9.bell- labs.com/wiki/plan9/)

        Connection refused: plan9.bell-labs.com:80

I can't access any of the above... :(

<comment><AUTHOR> I guess news.ycombinator.com sent them more traffic than they are accustomed to. Oops... Sorry guys.

<comment><USER9> Solution: stop webserver? :P

<comment><AUTHOR> What do you bet their web server fell over? It smells like some kind of a process failure.

<comment><USER8> It's still inaccessible for me.

I tried different browsers, proxies, Tor, and tried accessing from a remote shell running lynx. No go...

It's too bad, as I am a distro-hopper, and would like to be able to access Plan9 related online compendia if I'm going to be using Plan9.

        Edit:

Thanks for the link @ nanofortnight

<comment><USER10> I think that server is pretty skunkworks, and when it goes down on a weekend it doesn't get restarted until somebody comes in on Monday.

</comment></comment></comment></comment></comment></comment><comment><USER11> Woah: I didn't realize there was still active work on plan 9. They've participated in Gsoc the past four years even!

</comment><comment><USER12> One of my favorite features of Plan 9 is the extremely powerful filesystem abstraction through the 9p file protocol. It is incredible how clean becomes the design of the applications and the communication between the modules with a simple file interface. Currently I'm working on potential extension of this idea - an ontology-based virtual filesystem, where the files are replaced by objects and the organization is defined by relations, instead of the hierarchical structures.

<comment><USER13> 9p is really cool. I've seen a lot of papers about it, and some experiments done at university.

[https://code.google.com/p/diod/wiki/protocol#Sample_Session](https://code.google.com/p/diod/wiki/protocol#Sample_Session)

[http://graverobbers.blogspot.com/2007/08/v9fs-performance- ve...](http://graverobbers.blogspot.com/2007/08/v9fs-performance-versus- nfs.html)

[http://9p.cat-v.org/implementations](http://9p.cat-v.org/implementations)

</comment></comment><comment><USER14> Interesting. Serendipitously, I just came across some GSOC posts regarding getting Java on it:

[https://groups.google.com/forum/m/#!forum/plan9-gsoc](https://groups.google.com/forum/m/#!forum/plan9-gsoc)

If that turns out OK and someone manages to port a browser over, it might be a good environment to do run Clojure.

</comment><comment><USER15> I think to really understand what makes Plan 9 great requires a deep understanding of Unix, but once you have a deep understanding of Unix...

<comment><USER16> Plan 9 was basically the successor of Unix by the same research group, more modern, taking the ideas of Unix further, a distributed operating system with full network transparency, better shell (actually, rc already replaced the Bourne shell in version 10 Unix) and lots of other goodies such as the plumber. And it served as the "reference implementation" for UTF-8.

<comment><USER15> I understand all that. My point was that if you know enough to appreciate Plan 9 then you know enough to take advantage of the *nix ecosystem as it exists today, which is far too mature for Plan 9 to catch up to. We can always dream though...

<comment><USER8>
        lull them into thinking that Plan 9 is Just Another Unix.

From what I read, Plan9 has its own concepts which are not Unix analogues, thereby discounting Unix knowledge due to divergence.

</comment></comment></comment></comment><comment><USER17> Considering plan9 is so great for distributed computing, those with Big Data experience, do you think it is only a matter of time before plan9 replaces other operating systems being used in map-reduce, clustered environments?

</comment><comment><USER18> A bit sad that the page is down.

However, people interested into (vanilla) Plan 9 might also be interested in this:

[http://code.google.com/p/plan9front/](http://code.google.com/p/plan9front/)

</comment><comment><USER19> Plan 9 was also slow and didn't support a normal version of GCC.

Developers! Developers! Developers!

<comment><USER20> That's partly due to historical reasons I think. Some of the platforms they intended to run Plan 9 on had very buggy GCC ports. It's also worth noting that that the "native" Plan 9 compilers had some quirks of their own (see [http://doc.cat-v.org/plan_9/4th_edition/papers/compiler](http://doc.cat-v.org/plan_9/4th_edition/papers/compiler) ). It was never really intended to be a very familiar Unix environment, and they tried to straighten up a couple of things even in the way software is written. There is a POSIX environment available (the APE) but I don't know much about it, I never really tried it.

To be fair, between the "good enough" phenomenon and the licensing problems, it never really took off, which is rather sad.

</comment></comment><comment><USER21> It's a revolutionary OS hampered by licensing.

Open source the goddamn thing to save its ideas at this point before they are lost to nerd-history and let's see what happens.

<comment><USER22> Plan9 been free and open source for over a decade (2003). At first it was released with some very unusual constraints(Lucent Public License v1.0). But those were quickly lifted(Lucent Public License v1.02).

GNU's stance on the revised license seems mostly favorable with some mild reservations: [http://gplv3.fsf.org/wiki/index.php/Lucent_Public_License_ve...](http://gplv3.fsf.org/wiki/index.php/Lucent_Public_License_version_1.02)</comment></comment>


GIFwrapped – Share GIFs right from your iPhone - <AUTHOR> http://gifwrapped.co/

<comment><USER2> Downloaded, started browsing. I noticed about 50-50 sucess rate of it actually playing the GIF's I had saved to my phone.

I'm wondering if this has to do with the size limit IOS allows for saved images or the app itself. I'm not an app developer so I have no clue.

<comment><USER3> Eeek! Only 50-50? I'd love to see if I can improve that for you.

Could you either send an email to email@example.com or create a support request (link below) so I can get to the bottom of this? If you could attach a couple of the non-working gifs, that'd be helpful too! :)

[http://support.jellystyle.com/discussions/gifwrapped](http://support.jellystyle.com/discussions/gifwrapped)</comment></comment>


What being featured on the Google Play Store looks like (graph on right-side) - <AUTHOR> https://play.google.com/store/apps/details?id=com.platinumapps.platinumtasks

<comment><USER2> Anyone else think actual statistics and analysis would be more interesting than just another link to download the app that HAPPENS to have an extremely vague graph?

</comment><comment><USER3> It is very interesting, I would love to see the ratings on the same time line, to see if ratings are going up or down.</comment>


Interesting On-Boarding Hypotheses from Patreon - <AUTHOR> https://brianbalfour.com/essays/patreononboarding-growth <comment><USER2> correct link is [https://brianbalfour.com/essays/patreon-onboarding- growth](https://brianbalfour.com/essays/patreon-onboarding-growth)

<comment><AUTHOR> _Facepalm_ what a miserable failure. Reposted: [https://news.ycombinator.com/item?id=19728461](https://news.ycombinator.com/item?id=19728461)

</comment></comment><comment><USER3> Anyone else find the Patreon experience very slow and janky? The entire experience feels like a bootcamp final project and not a company with top engineering talent 5+ years in the making.

</comment><comment><USER4> it's a horrible plattform to upload content to. Maybe I haven'T found it yet, but deviantart has an ftp upload interface</comment>