Monday, November 18, 2019

No Do-Over for New Orleans Hard Rock Hotel


There is a saying I've heard more than once from fellow engineers involved in a rush job:  "There's not enough time to do it right, but there's always enough time to do it over."  In other words, sometimes the only way managers will give engineers enough time to do a thing right is if it fails the first time.  Unfortunately for three construction workers who died and numerous other people injured and otherwise harmed by the collapse on Oct. 12 of the Hard Rock Hotel under construction in New Orleans, there will not be any do-overs.  On Nov. 13, New Orleans officials announced that the severely damaged hotel structure will be imploded and razed to the ground.  This will bring to a sad end the physical aspects of the tragedy that began last October, but won't by itself answer the questions of why the collapse happened. 

In the weeks since the collapse, a video emerged that was made by a construction worker on site just two days before the accident.  It shows severely bowing supports between the just-poured top floor and the floor below it.  A reporter for WWL-TV posted a story in which another construction worker said that temporary supports between the top two floors were removed only three days after the concrete was poured.  The same report cites industry standards that say the minimum time between pouring and removing temporary supports should be two weeks.  Reportedly, workers were under heavy pressure by supervisers to complete the building before the busy Mardi Gras tourist season in February. 

Another WWL report says that a large swimming pool was apparently lifted by crane to the top of the building just hours before the collapse.  Even if empty, a swimming pool shell must weigh several thousand pounds, adding additional stress to concrete that was possibly already weakened by the premature removal of supports. 

While these facts raise suspicions, no definite conclusions can be drawn until the official investigations now underway are completed.  Nevertheless, the accident and what is known about it so far serve as reminders of some age-old truths about engineering that are always helpful to remember.

First, practical engineering is always a business of compromises.  Any engineering project is an attempt to stay within multiple limits:  limits of cost, limits of time, limits of physical capabilities of materials, limits of hazards, and so on.  A project is deemed to be successful when it achieves something desirable without exceeding any of the important limits that applied to it.  Sometimes one or two limits are exceeded, but if the consequences of exceeding these limits are minor, they can be neglected.  For example, if a project slightly exceeds budget or is completed only a few days late, usually those involved just absorb the cost and keep going.

It begins to look like the Hard Rock project put speed above a lot of other priorities, including safety.  Now, construction projects can be completed faster than the average time that is usually allotted to them.  To some extent, money can be traded for time.  I recall a passage from the autobiography of Albert Speer, Hitler's architect who later became Germany's Minister of Armaments and War Production during World War II.  Right after Hitler hired him in the 1930s, Speer was handed the job of redecorating the official residence of the Minister of Nutrition for Hitler's associate Joseph Goebbels, and Speer promised to do the job in the exceptionally short time of only two weeks.  In order to impress his new boss, Speer spent extra money on three shifts of additional workers and rented big fans to blow drying air through the building to dry the paint faster, and reported completion to his boss right on schedule.

Not that Nazis are moral exemplars by any means.  This is just a historical anecdote showing how construction projects can be safely sped up at additional cost.  But concrete is not as forgiving as paint.  There are special fast-setting concrete mixtures, but even those require the specified minimum time to set, and tests are required to verify that the concrete is firm enough to hold its own weight without extra supports that are installed during the pouring process. 

It's easy to watch a construction site with workers swarming around it like bees, and think that everything just goes smoothly by default or instinct.  What is not visible to the eye is the complex management structure that has to be in place in order for the dozens or hundreds of lowest-level workers to know what they are supposed to do, and when and how they are supposed to do it.  Having engaged in management myself just enough to know I don't like it, I can only imagine what it takes to run a large-scale building project such as the hotel that collapsed in New Orleans.

In the coming months and years, lawyers as well as official investigators will dissect the management structure, the physical structure, and the complex sequence of events that led to the tragedy of Oct. 12.  Major disasters rarely have a single cause without which everything would have been just fine.  A combination of factors is usually at fault, so we may find that schedule corner-cutting, weather conditions, and an unfortunate sequencing of events such as raising the swimming pool to the top of the building were all partly responsible for the collapse.  But until this information is made public, we can only speculate.

In the meantime, the loved ones and friends of two workers whose bodies remain in the rubble will have to wait until after the intentional implosion of the building to find if there is anything recoverable.  The structure is still unstable and too dangerous to search in, even after an attempt to implode the damaged construction cranes on the site.  And the construction and engineering communities await the post-mortem on this major tragedy to learn whatever lessons can be learned from it. 

Sources:  I referred to an article carried on www.nola.com on Nov. 1 at https://www.nola.com/news/article_64e1c72a-fcf3-11e9-b3a6-a723e997693e.html, an article republished by USA Today from the Lafayette Daily Advertiser on Nov. 13 at https://www.usatoday.com/story/travel/news/2019/11/13/hard-rock-hotel-new-orleans-to-be-demolished/4180871002/, and an article on the WWL-TV website describing the swimming-pool lift at https://www.wwltv.com/article/news/investigations/pool-lifted-to-rooftop-of-hard-rock-hotel-just-hours-before-collapse/289-6d12ee9e-0379-4837-a946-1d1b7b66ba94.  The anecdote about Goebbel's official residence is on p. 32 of Albert Speer, Inside the Third Reich (Macmillan, 1970).  I thank David Jenkins for bringing my attention to some of this additional information.

Monday, November 11, 2019

Is Vitamin E Acetate Killing Vapers?


Officials at the U. S. Centers for Disease Control announced Friday that they may have found a cause for the lung injuries and deaths in people who use e-cigarettes.  Since the problem arose last March, a total of 39 people have died from what is now being called "e-cigarette, or vaping, product use associated lung injury," (EVALI for short) and over 2,000 more have become ill or hospitalized.  A report by National Public Radio says that a compound called vitamin E acetate (tocopheryl acetate) has been found in lung-fluid samples from 29 individuals who were hospitalized as a result of vaping.  While the CDC has not reached any definite conclusions that vitamin E acetate is the sole cause of EVALI, the fact that it has been found in all 29 samples is significant.  The compound is known to be used by off-label manufacturers who sell vaping products containing THC—the active ingredient in marijuana.  Most but not all EVALI victims admit using vaping mixtures containing THC.

Vitamin E acetate is a more stable form of pure vitamin E (tocopherol), and the acetate is used in a wide variety of consumer products meant to be applied to the skin or swallowed.  It is an oil-like substance that is innocuous in these applications, but inhaling vaporized oily materials can lead to serious lung problems.  The syndrome called "lipoid pneumonia" can strike people whose job involves breathing vaporized oils.  For example, a performer who "eat sfire" by sticking flaming objects in his mouth will often prepare for his stunt by coating his mouth with a petroleum-jelly-like substance called kerdan.  If the hot object happens to vaporize some of the kerdan and the unfortunate performer breathes the vapor, the oil can coat the inside of his lungs and cause lipoid pneumonia.  A less exotic way of getting the disease is to take a mineral-oil laxative and have it go down your trachea instead of your esophagus (the wrong way.)  So it's entirely reasonable to believe that lipoid pneumonia is what the sick vapers are getting, and that vitamin E acetate may be the cause.

This situation is beginning to resemble another famous incident in which manufacturers involved in making a psychoactive substance turned to what they thought was a harmless chemical in order to cut corners, only to find that it poisoned their customers. 

During Prohibition in the U. S. (1919-1933), it was illegal to sell intoxicating beverages containing more than a few percent of ethyl alcohol.  One of the few exceptions was made for extracts of essential oils such as vanilla and ginger, which were typically 70% alcohol.  When sales of such products boomed and it became clear that people weren't just making lots of vanilla ice cream and gingerbread cookies with the extracts, the Food and Drug Administration required makers of these extracts to adjust their formulas so that they were undrinkable in concentrated form, a process called denaturing.  In particular, makers of Jamaica ginger had to add bitter-tasting substances like castor oil that would not interfere with the intended use for ginger flavoring, but would discourage would-be alcohol consumers from drinking the stuff just to get a buzz.  In order to enforce these rules, the FDA would audit samples of Jamaica ginger to make sure that when the alcohol boiled off, the remaining solids were heavy enough to satisfy the auditors that the makers were still denaturing their product properly.

Thus the matter stood until the price of castor oil went up in the late 1920s.  One Jamaica-ginger maker named Harry Gross looked around for a substitute chemical and found one called tri-ortho cresyl phosphate (TOCP for short).  He asked the manufacturer, Celluloid Corporation, if the chemical was toxic, and they told him they didn't think so.  But this was simply based on the fact that no one involved in the making of the chemical had become seriously ill, not that any tests on animals or humans had been made.  TOCP had a suitable specific gravity to be substituted for castor oil, so Gross made up a large batch of several barrels and sold it to retailers, who in turn sold it to their mostly poor customers who couldn't afford good bootleg liquor.

In a few months, doctors in the poorer areas of cities, especially in the South, began seeing patients whose legs were not working right.  It turned out that TOCP was a slow-acting neurotoxin that selectively attacked the nerves going to the leg muscles.  Over the next year or so, thousands of victims of what came to be called "jake-leg syndrome" turned up.  Many were permanently paralyzed and spent the rest of their lives in wheelchairs, if they could afford one. 

Gross eventually served a two-year jail sentence for adulterating his product, but there were no other major legal consequences for the manufacturers, or compensation benefits for the thousands of mostly poor victims of the syndrome. 

The parallels to the current vaping crisis may not be as obvious as they seem.  But in both cases, there is a chemical being sold under dubious circumstances by shady operators.  In both cases, the chemical involved was not previously suspected of being harmful.  And in both cases, serious injuries occurred to thousands of people before anything substantial was done to get to the source of the problem.

In contrast to the jake-leg episode, the CDC has been issuing warnings about vaping products almost since the first victims of EVALI were identified.  But the drive that some people feel to get high can overpower caution and common sense, and there will always be those around who are willing to cater to such desires with a potentially dangerous product.

It looks like the CDC may be getting to the bottom of the problem, and if they do, we can expect quick action against anyone selling vaping products that can harm users.  While the free market has its uses, regulations to protect the public typically arise only after serious widespread harm has been done due to lack of regulation, and that may be what happens in this case. 

Sources:  The NPR article "CDC Finds Possible Culprit In Outbreak Of Vaping-Related Lung Injuries" appeared on Nov. 8, 2019 at https://www.npr.org/sections/health-shots/2019/11/08/777646890/cdc-finds-possible-culprit-in-outbreak-of-vaping-related-lung-injuries.  I also used material from the health website Healthline at https://www.healthline.com/health/lipoid-pneumonia#causes.  I blogged on this matter on September 9, 2019 at https://engineeringethicsblog.blogspot.com/2019/09/vaping-turns-deadly.html.  And an excellent longer article detailing the saga of jake-leg syndrome ("Jake Leg" by Dan Baum) appeared in The New Yorker magazine's Sept. 15, 2003 issue beginning on p. 50, to which I referred for some of the information above, as well as Wikipedia articles on Jamaica ginger and vitamin E. 

Monday, November 04, 2019

Moral Exemplars Still Wanted: "The Current War: Director's Cut"


One way of teaching engineering ethics that is less grim than picking through wreckages of failed projects is to portray moral exemplars:  engineers who did the right thing in a critical situation and benefited people thereby.  For example, William LeMessurier, a structural consulting engineer, played a prominent role in determining that the 60-story Boston skyscraper formerly known as the John Hancock Tower was unstable in certain types of wind loading.  The analysis he and his colleagues produced convinced the owners to install millions of dollars' worth of cross-bracing, and the building is still standing today. 

For many generations both in the U. S. and abroad, Thomas Edison was a heroic inventor whose ideas benefited millions.  In 1940, at the height of the inventor-as-hero period in U. S. history, MGM brought out a pair of panegyrics based on his life: "Young Tom Edison" starring Mickey Rooney, and "Edison the Man" with Spencer Tracy.  I must confess that seeing the the former film on TV played a disproportionately large role in my decision to become an electrical engineer, around the age of eight.

However, cinematic heroes today tend to be mainly of the comic-book variety, so when "The Current War:  Director's Cut" was finally released after a two-year delay connected with the fall of Harvey Weinstein, whose production company financed the film, I could hardly wait to see what a present-day director and actors would do with the raw material.

And some of it is pretty raw.  There was no hint in the MGM flicks that Edison was ever anything less than selfless as he enthusiastically searched for innovations that would be boons for humanity.  In particular, there was nothing about the admittedly sordid tricks he pulled to make George Westinghouse's rival AC system look like a threat to public safety, up to and including killing horses and pigs (but not an elephant, as was falsely attributed to him by some confused reports of an elephant's electrocution he filmed at Coney Island in 1903).  But in "The Current War," Benedict Cumberbatch's Edison is no one's idea of a moral exemplar, though he would qualify as perhaps an object of pity.

Just the kind of historic rabbit-trail I took you on about the elephant is one of the problems with the film.  Despite the director's thoughtful inclusion of little side-titles when new characters are introduced (I particularly liked "Nikola Tesla, futurist"), the people I saw the film with all complained that it was very hard to follow.  Although I have made somewhat of an amateur study of Edison, Westinghouse, and that era of the history of technology, I myself had trouble figuring out who was who unless the side-titles were there to help.  In particular, there was an older bewhiskered gent who seemed to be Westinghouse's technical Svengali, but who was only addressed as "Frank."  At the time I guessed it was Frank Sprague, who played a prominent role in early electric tramways.  But later in the film it turned out he was Franklin Pope, an "electrician" (which was what electrical specialists sometimes called themselves back then) who died, not trying to get Westinghouse's electric fan motor to work as the film implied, but in trying to fix a motor-generator installed in the home of his own basement.

As most historical films have to do, this one takes dramatic license with the facts, but stays reasonably close to the main narrative, which is the battle between Edison's first-to-the-market but ultimately unsuccessful DC system, and Westinghouse's cheaper and better alternative of AC, which is still with us today.  The climax of the MGM Spencer Tracy flick, which was Edison's invention of the light bulb, is relegated to a long speech by Cumberbatch at the 1893 World's Columbian Exposition in Chicago.  Westinghouse won the bid to light up the fair, and that triumph symbolized the end of the current war.  Westinghouse and Edison run into each other at the Japanese exhibit, and Westinghouse asks Edison what it felt like to invent the light bulb.  What ensues is perhaps the best piece of classical acting I've seen Cumberbatch do—no special effects, no superhero action, just a man painting a picture of a scene with words that answers the question better than any number of adjectives. 

Cumberbatch seems to be making a career of portraying emotionally peculiar geniuses:  first as the legendary Sherlock Holmes, then as the eccentric mathematician and code expert Alan Turing, and now as Edison.  Critics of the film say he does a good job of portraying our era's idea of the corporate genius:  the Steve-Jobs-type disrupter of the status quo who nevertheless betrays his usually-suppressed emotional life by playing back the voice of his dead wife on his new invention, the phonograph.  Edison's first wife Mary did die in the midst of the current war, which only added to his distress and frustration.  But he didn't let her death slow him down in pursuing his goals by whatever means he thought necessary, including secretly cooperating with a man who thought electrocution would be better than hanging condemned criminals.

I suppose I should have put a spoiler alert on that last paragraph.  But it's unlikely that too many people will see the movie just for the suspense.  To techno-nerds such as myself, who are familiar with many of Edison's lesser-known inventions, the film was a feast of seeing cinematic reproductions of things like the first kinetograph projector (an early form of motion-picture machine) and his electric pen for writing on paper for mimeograph reproduction.  And the film gets some humor out of the Edison family's alleged habit of secretly communicating with each other via Morse-code taps. 

But for the average viewer who has little or no prior knowledge of the era, I'm afraid the film will be a rather confused mish-mosh of mysterious devices, obscure motives, and hard-to-identify characters. A strength of the film is that everything takes place against a lovingly-reproduced CGI background of 1890s America, including a panoramic view of the Columbian Exposition, complete with the original Ferris wheel, that ought to be issued as a two-by-three-foot poster on its own.  I'm not sure what effect the movie will have on eight-year-olds, but don't look for there to be a flurry of young people flocking to be electrical engineers in about ten years.  Actors, maybe, but not engineers.

Sources:  "The Current War:  Director's Cut" was released on October 24, 2019, and stars Benedict Cumberbatch as Thomas Edison.  I referred to a review of the film posted at https://www.thewrap.com/the-current-war-directors-cut-film-review-benedict-cumberbatch-tom-holland/ for details of the delayed release, and also Wikipedia information concerning the 1903 elephant electrocution of Topsy.

Monday, October 28, 2019

A Pilot and Software Engineer's Take on the Boeing 737 Max


As of this writing, the ill-fated Boeing 737 Max series of jetliners is still grounded after two fatal crashes in which the pilots lost a battle with the plane's Maneuvering Characteristics Augmentation system (MCAS).  The U. S. Federal Aviation Administration (FAA) grounded the planes last March, and current estimates are that the planes will not be flying again before at least  2020.  This is a huge blow to Boeing and its customers who bought the planes, as billions of dollars of assets are sitting idly on the runway instead of making money. 

Only a month after the planes were grounded, a software engineer named Gregory Travis, who is also a pilot, wrote his thoughts on what happened with the Max 8 and why he thinks the problem may be intractable.  A version of his article appeared on the website of IEEE Spectrum recently, and to my mind it is the most comprehensive and damning examination yet of a situation that put thousands of lives at risk and ended up killing 346 people.

Travis points out that the 737 series was introduced all the way back in 1967.  Designing an airframe from the bottom up is a costly enterprise, so Boeing understandably would like to make incremental changes to an existing design rather than coming up with a whole new airplane every few years.  As fuel economy became more important for airlines, Boeing decided to go with more efficient engines, which for fundamental physical reasons have to be larger.  But eventually, the newer engines got so big that the ground clearance in their original positions was too small—the front fans were going to hit the ground if they didn't move the engines.  So they did move them upward and back.  But that caused another problem.

Travis drew on his experience as a pilot to note that you start playing with the fundamental handling characteristics of an aircraft when you move the engines around.  Stable flight is a complex interplay between the engine thrust vector and the center of gravity, the drag on the wings and other surfaces, and many other factors.  When the engines were moved, it made the plane tend to pitch upward with increased power, and this is not a good thing.  Upward pitch is to an airplane what tilting your head up is to your head. 

If an aircraft's pitch exceeds a certain angle, depending on the angle of attack (the angle between the plane's fuselage and the air moving past it), it can stall, which basically makes it fall out of the air.  The modified 737 was edging dangerously close to a dynamically unstable condition, which is not something a commercial airliner should do.  Travis said that the right thing to do at this point would have been to redesign the whole airframe to deal with the changed position of the engines.  In his words, "The airframe, the hardware, should get it right the first time and not need a lot of added bells and whistles to fly predictably. This has been an aviation canon from the day the Wright brothers first flew at Kitty Hawk." 

But instead of doing that, Boeing chose to develop a software patch that included the MCAS—a complicated system of interacting compensation fixes, pilot warnings, and poorly considered feedback loops that were vulnerable to faulty inputs from angle-of-attack sensors, which can easily be fooled by surface winds or other transient phenomena. 

Most modern airliners are "fly-by-wire" systems in which there is no direct mechanical connection between the pilot's stick and pedals, and the airplane's control surfaces.  Instead, a computer both takes in the pilot's commands and feeds back to the pilot something approximating the "feel" of manually operated controls, so that the pilot senses he or she is flying a plane and not a video game.  But the MCAS was apparently designed so that when it sensed a situation in which the nose needed to be pointed down, it would in effect grab the controls away from the pilot and do what it knew was right—even if it was wrong.  And the feedback motors that would do this were simply too powerful for the pilots to overcome.  In a reference to the famous HAL 9000 computer in the film 2001: A Space Odyssey, in which the computer tries to kill everyone on board for its own rather obscure purposes, Travis writes "MCAS gaslights the pilots. And it turns out badly for everyone. 'Raise the nose, HAL.' 'I’m sorry, Dave, I’m afraid I can’t do that.'"

We are well down the road that leads to 100% control of airplanes by robotic systems.  Nevertheless, we are far from arriving, and in the meantime there has to be effective and safe cooperation, not competition, between the human pilots and the software that runs the plane.  But in trying to cut corners by fixing an airframe problem with software, and poorly designed software at that, Boeing may have painted itself, and all its customers who bought 737 Max 8s, into a corner that it can't get out of.  Every month that goes by without an FAA-approved plan to fix or retrofit Max 8s so they can fly safely again is an indication that the problem revealed by the MCAS-related crashes may be deeper and more far-reaching than most people thought at first.  The fact that an engineer with deep expertise in both software and flying saw what was evidently going on within a month of the groundings tells me that he's probably on to something.

The historian of technology Henry Petroski says that engineers often learn more from failures than from successes.  We should learn a lot from the 737 saga, but it may prove to be an expensive lesson.  The 737 Max began commercial flights only in 2017, and I'm sure Boeing and its customers were counting on many years of revenue from their purchases.  If the design ends up being scrapped, it will amount to the largest recall in aviation history.  But if even just most of what Travis says is true, that is well within the realm of possibility.  Regardless of what patches Boeing may come up with, I'm never going to feel entirely comfortable flying in a 737 Max again. 

Sources:  Readers are urged to see Travis's complete article, which goes into greater depth than I have been able to here.  It is on the website of IEEE Spectrum at https://spectrum.ieee.org/aerospace/aviation/how-the-boeing-737-max-disaster-looks-to-a-software-developer.

Monday, October 21, 2019

Hard Rock Hotel Collapse: Why?


On Saturday morning, Oct. 12, a hotel under construction at the corner of Rampart and Canal streets in New Orleans, Louisiana underwent a partial collapse, killing three workers and injuring 30.  The Hard Rock Hotel, originally planned as a mixed retail/residential project, had reached a height of 13 stories when something happened to cause a collapse at the top completed level.  A chain of floor collapses ensued, leading to a partial collapse of all the floors above about the seventh level.  The collapse also damaged the two tower cranes that were being used on the project, leading to concerns that they might fall and damage some of the surrounding structures in the densely populated downtown area.  At this writing (Wednesday, Oct. 16), the body of one worker has yet to be recovered.

Any time a construction accident occurs, the entire complex process of planning, management, and actual construction activity gets called into question.  The construction of a large high-rise such as the Hard Rock Hotel is an exercise in meticulous coordination and integration of technologies ranging from computer-aided design to the kind of pumps that can send many tons of concrete all the way up to the roof of a 13-story building.  With so much heavy stuff being supported in temporary ways, it's understandable that something could go wrong. 

For example, the concrete floors that are poured at each level have to set before they are put into compression by tensioning cables.  Try to tighten those cables too early, and you're liable to squash the still-weak concrete.  But wait too long by a day or so, and you've added costly time to the construction schedule.  A huge number of time-critical matters have to be coordinated within a small margin of error for things to go smoothly, and weather, supplier problems, and other external factors can throw a monkey wrench into the works. 

Still, most buildings go up without having multiple floors collapse on each other.  Viewed from the front, the structure looks like a giant finger just scraped all the floors above the seventh and bent them downward. 

A structural engineer named Walter Zehner once worked on the project in its early stages.  When contacted by a reporter from the Lafayette Daily Advertiser, he said that it was much too early even to speculate on the cause of the collapse.  After retreival of the remaining fatality, engineers will have to stabilize the structure so that it won't present an ongoing hazard to surrounding buildings.  Only then will the investigation begin, and it might take months.

Construction was in progress at the time of the collapse, and Zehner says that the remaining eyewitnesses will be asked what exactly was being done at the time.  It's possible that someone accidentally knocked over a support column, for example.  If a heavy just-poured layer of concrete falls twelve or fifteen feet onto the floor below it, the impact could well cause the next floor to collapse, leading to just the kind of destruction that took place.  But all such notions are speculation at this point, and the investigation will reveal a sequence of events that may be traced backwards to a possible cause.

In the recent past there have been some indictments of city inspectors for taking bribes.  A lack of proper municipal oversight might lead to hazardous conditions that could cause such a collapse, but again, this is speculation. 

The most recent collapse of a structure under construction that was covered in this blog was the Florida International University pedestrian bridge collapse in Miami in 2018.  Six people were killed when a concrete-beam bridge collapsed just after being set in place.  The investigation of that accident is still ongoing, but late last year it was revealed that the National Transportation Safety Board (NTSB) had determined design errors were at least partly to blame. 

Accidents like the Hard Rock Hotel collapse can happen even if the plans are flawless.  The 1981 collapse of a pedestrian walkway inside the atrium of the Hyatt Regency Hotel in Kansas City was due not to any flaws in design, but to a compromise that the builder made in the support structure during construction.  Investigations may reveal that while the New Orleans hotel plans were correct, the builders may have overlooked something.  Or it could turn out that a single mistake made by one construction worker led to the tragedy. 

Not much is known about the extent of training that typical construction workers receive.  Construction is one of the few remaining fields in which a person without a high-school degree can earn at least in the range of $13 an hour, which is the average construction-worker wage in Louisiana according to a statistic cited by the website indeed.com.  This is scarcely anything to write home about, unless home is Guatemala, in which case it looks good compared to trying to be a subsistence farmer.  Nevertheless, it's attractive enough to draw workers who are willing to face the dangers and difficulties that construction work involves, up to and including the chance of dying in a tragic accident.

We will have to wait to find out what exactly happened in New Orleans to transform a nearly completed building into a pile of dangerous rubble.  And when we do, I hope that any lessons learned will be applied to future construction sites so that tragedies like this happen less and less frequently. 

Sources:  I referred to reports from the ABC News website at https://abcnews.go.com/US/search-underway-unaccounted-person-hard-rock-hotel-partially/story?id=66261708, the Lafayette Daily Advertiser website at https://www.theadvertiser.com/story/news/2019/10/14/hard-rock-hotel-collapse-new-orleans/3979427002/, and the Wikipedia website "List of structural failures and collapses."  The hourly construction wage statistic came from https://www.indeed.com/salaries/Construction-Worker-Salaries,-Louisiana.  I discussed the FIU bridge collapse at https://engineeringethicsblog.blogspot.com/2018/12/design-flaw-identified-in-fiu-bridge.html.

Monday, October 14, 2019

PG&E Pulls the Fire Plug


If you were one of an estimated two million customers of Pacific Gas & Electric in northern California this week, your power went off for a day or more.  There was no malfunction of the power grid.  Instead, the utility deliberately shut off power in large regions where high winds were predicted, in order to avoid sparking forest wildfires of the kind that have killed over a hundred people in recent years.  During the outage, the utility's website crashed, making it difficult or impossible for people to find out if they lived in an area targeted for an outage.  According to an article about the blackouts in the Wall Street Journal, California Governor Gavin Newsome reacted with "outrage," blaming the precautionary outages on PG&E's "greed and mismanagement over the course of decades."  PG&E CEO Bill Johnson said he might have some disagreements with Gov. Newsome, but that he was not ruling out similar outages in the future.

Reliable electric power is one of the mainstays of modern civilization.  Because most utilities outside large cities rely on above-ground transmission and distribution lines, their power grids are subject to what the lawyers call acts of God:  windstorms and ice storms that down power lines, lightning and floods that damage and destroy equipment, and other natural occurrences that disrupt the smooth delivery of power.  As long as these interruptions are rare and end promptly, no one blames the utility for them.  But the deliberate large-scale blackouts PG&E imposed simply as a precautionary measure are something new.

The Journal article points out that California now has a law making utilities liable for any damage caused by fires that are ignited by their lines, even if the utility was not negligent.  This law contributed to over $30 billion in potential liability costs associated with power-line-sparked wildfires and was a big reason why PG&E went into bankruptcy proceedings at the beginning of this year.  I don't know the history of that particular law, but it's consistent with a blame-the-powerful attitude that also seemed to inspire Gov. Newsome's comments.

Blaming the powerful is one thing, especially if they're guilty, but crippling a vital utility through excessively punitive laws is another thing.  The parties to this conflict include PG&E's management, workers, and investors, who mainly just want to do their job and/or get paid for it; PG&E's customers, who want reliable electric power without having their houses burn down; and the rest of California, which includes its government, along with the accompanying laws and regulatory environment.  Each group has interests that potentially conflict with the others, and these blackouts highlight the areas of conflict.

I lived in California for the four years of my undergraduate degree outside of Los Angeles in the 1970s, and I vividly recall waking up one day to see a dark cloud of smoke covering the entire northern half of the sky as a wildfire burned out of control in the San Gabriel Mountains.  Even back then, I thought people built houses in crazy places in California, on the edges of cliffs and so on, and it's only gotten worse since then.  Fires that used to damage nothing but wildlife (which is bad enough) now threaten whole communities, and so the need to control them by whatever means necessary has grown in recent years.

Part of that control is making sure that no tree can come anywhere close to a high-voltage transmission line.  PG&E has a tree-trimming program, but they admit they are behind in their scheduled trimming operations, and they also lack the ability to monitor winds at many specific locations so as to restrict the power outages to where they are really needed.  And even if they had such monitoring abilities, their older equipment doesn't allow them to be very selective in the power lines they de-energize—hence the massive blackouts covering a wide area. 

From here, the outages look like a desperate move by a utility company that is hamstrung by regulations and unfavorable laws.  If PG&E was a human being and not a large corporation, it would strike me as unfair to make him liable for damage even if negligence could not be proved.  If a driver is in a situation where he is obeying all the traffic laws, and a child suddenly runs out from a hidden place and gets hit, the driver generally does not get penalized if there was nothing he could have done to avoid the accident. 

But if you have an attitude that large private corporations are infinite money pots from which lawyers and their clients can extract indefinite amounts of money, sooner or later you run up against reality.  If PG&E doesn't have enough money or staff or freedom from regulations to cut away all their trees from their lines, and they risk the corporate equivalent of death if their lines cause a fire, then the precautionary blackouts look like the least bad alternative. 

Civilization is a huge mesh of cooperation:  buyers cooperating with sellers, consumers cooperating with producers, and government, one hopes, encouraging the virtuous kind of cooperation that leads to prosperous and flourishing societies.  But when groups begin to view other groups mainly as enemies and attribute malign motives to them, you can end up with a kind of self-fulfilling prophecy.  The maligned group or entity may think, "Well, these folks believe I'm a bad hombre no matter what I do, so I might as well act like it." 

The precautionary wind blackouts are a sign that maybe PG&E has been pushed too far.  We can hope that a spirit of conciliation can prevail so that more trees can be trimmed, more customers served more reliably, and fewer fires lead to tragedy in the future.  But right now, the prospects for that don't look too bright.  Especially if you're power's out.

Sources:  The Wall Street Journal article "PG&E's Big Blackout is Only the Beginning" appeared on Oct. 12, 2019 at https://www.wsj.com/articles/pg-es-big-blackout-is-only-the-beginning-11570909816.  I also referred to a New York Times article at https://www.nytimes.com/2019/10/09/us/pge-shut-off-power-outage.html.

Monday, October 07, 2019

Pilot Overload and the Boeing 737 Max Accidents


In the last couple of months, new information about the factors leading to crashes of two Boeing 737 Max aircraft and the loss of 346 lives has emerged.  All such aircraft were grounded indefinitely last March after investigators found that a software glitch combined with faulty data from airspeed indicators to start a chain of events that led to the crashes.  Airline companies around the world have lost millions as their 737 Max fleets sit idle, and Boeing has been under tremendous pressure from both international regulatory bodies and the market to come up with a comprehensive fix for the problem.  But as long as both humans and computers have to work together to fly planes, the humans will need training to deal with unusual situations that the computers come up with.  And in the case of the Lion Air and Ethiopian Air crashes, it looks like whatever training the pilots received left them inadequately prepared to deal with at least one situation that led to tragedies.

Modern fly-by-wire aircraft are certainly among the most complex mobile systems in existence today.  It is literally impossible for engineers to think of every conceivable combination of failures that pilots would have to handle in an emergency, simply because there are so many subsystems that can interact in almost countless ways.  But so far, airliner manufacturers have done a pretty good job of identifying the major failure conditions that would be life-threatening, and instructing pilots about how to deal with those.  The fact that Capt. Chesley Sullenberger was able to land a fly-by-wire Airbus A320 plane in the Hudson in 2009 after experiencing failure of all engines shows that humans and computers can work together cooperatively to deal with unusual failures.

But the ending was not so happy with the 737 Max flights, and recent news from regulators indicates that a wild combination of alarms, stick-shakings, and other distractions may well have paralyzed the pilots of the two planes that crashed after faulty readings from angle-of-attack sensors set off the alarms. 

Flying a modern jetliner is a little bit like what I am told it was like being in the army during World War II.  For many soldiers, the experience was a combination of long stretches of incredible tedium interrupted by short but terrifying bursts of combat.  It's psychologically hard for a person to remain alert and ready for any eventuality when the norm is that pretty much nothing out of the routine ever happens the vast majority of the time.  So when the unusual failure of both angle-of-attack sensors led to a burst of alarms and the flight computer's attempt to push the nose down, the pilots on the ill-fated flights apparently failed to cope with the confusion and could not sort through the distractions in order to do the correct thing.

A month after the Lion Air crash in 2018, the FAA issued an emergency order telling pilots what to do in this particular situation.  Read in retrospect, it resembles instructions on how to thread a needle in the middle of a tornado: 

            ". . . An analysis by Boeing found that the flight control computer, should it receive faulty readings from one of the angle-of-attack sensors, can cause 'repeated nose-down trim commands of the horizontal stabiliser'.  The aircraft might pitch down 'in increments lasting up to 10sec', says the order.  When that happens, the cockpit might erupt with warnings.  Those could include continuous control column shaking and low airspeed warnings – but only on one side of the aircraft, says the order.  The pilots might also receive alerts warning that the computer has detected conflicting airspeed, altitude and angle-of-attack readings. Also, the autopilot might disengage, the FAA says.  Meanwhile, pilots facing such circumstances might need to apply increasing force on the control column to overcome the nose-down trim. . . . They should disengage the autopilot and start controlling the aircraft's pitch using the control column and the 'main electric trim', the FAA say. Pilots should also flip the aircraft's stabiliser trim switches to 'cutout'. Failing that, pilots should attempt to arrest downward pitch by physically holding the stabilizer trim wheel, the FAA adds."

If I counted correctly, there are six separate actions a pilot is being told to take in the midst of a chaos of bells and whistles going off and his plane repeatedly trying to fly itself into the ground.  The very fact that the FAA issued such a warning with a straight face, so to speak, should have set off alarms of its own.  And after the second crash under similar circumstances, reason prevailed, but first with regulatory agencies outside the U. S.  Finally, the FAA complied with the growing global consensus and grounded the 737 Max planes until the problem could be cleared up.

When software is rigidly dependent on data from sensors that convey only a narrowly defined piece of information, and those sensors go bad, the computer behaves like the broomstick in the Disney version of Goethe's 1797 poem, "The Sorcerer's Apprentice."  It goes into an out-of-control panic, and apparently the pilots found it was humanly impossible to ignore the panicking computer's equivalent of "YAAAAH!" and do the six or however many right things that were required to remedy the situation. 

It is here that an important difference between even the most advanced artificial-intelligence (AI) system and human beings comes to the fore.  It is the ability of a human being to maintain a global awareness of a situation, flexibly enlarging or narrowing the scope of attention as required.  Clearly, the software designers felt that once they had delivered an emergency message to the pilot, the situation was no longer their responsibility.  But insufficient attention was paid to the fact that in the bedlam of alarms that the unusual simultaneous sensor failure caused, some pilots—even though they were well trained by the prevailing standards—simply could not remember the complicated sequence of fixes required to keep their planes in the air.

Early indications are that the 737 Max "fix," whatever software changes it involves, will also involve extensive pilot retraining.  We can only hope that the lessons learned from the fatal crashes have been applied, and that whenever such unusual sensor failures happen in the future, pilots will not have to perform superhuman feats of concentration to keep the plane from crashing itself.

Sources:  A news item about how Canadian regulators are looking at the pilot-overload problem appeared on the Global News Canada website on Oct. 5, 2019 at https://globalnews.ca/news/5995217/boeing-737-max-startle-factor/.  The November 2018 FAA directive to 737 Max pilots is summarized at https://www.flightglobal.com/news/articles/faa-order-tells-how-737-pilots-should-arrest-runawa-453443/.  I also referred to Wikipedia's articles on the Boeing 737 Max groundings, Chesley Sullenberger, and The Sorcerer's Apprentice.