The Economics That Made Boeing Build the 737 Max

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This video was made possible by Wix. Build your website easily at wix.com/go/wendover. This is a 737 MAX—a brand new airplane… almost. It has a few aspects that makes it unique. Most modern airplane have electronic pre-flight checklists. The 737 MAX uses paper checklists. Most modern airplanes can be turned on by flipping a switch. The 737 MAX uses a seven step process. Most modern airplanes have electronic on-screen warnings describing exactly what a problem is. The 737 MAX only has a warning light. Most modern airplanes are fully fly-by-wire meaning their ailerons and elevators and other flight control surfaces move by electronic signals triggering servo motors. The 737 MAX has, running from the cockpit, physical cables themselves pulling most of the flight control surfaces to move. Not all of these design elements are necessarily bad things—many pilots, in fact, prefer the fly-by-cable system, for example—but there is one other big difference between most modern airplanes and the 737 MAX. Most modern airplanes are flying up above right now, the 737 MAX is not. These design elements are all indicators of a truth about the 737 MAX—it’s a 50 year old airplane retooled, re-engined, and redesigned three times to make it what it is today. It is the oldest major commercial plane-type still being made today and it shows. Much of of the design of the 737 MAX was done by people not even alive today. The reason Boeing revamped and revamped and revamped this airplane over and over and over again has to do with the economics of the aviation industry as a whole and of one of the world’s fiercest rivalries—Boeing versus Airbus. Back in 2011, rumblings were emerging that Boeing would design an all-new single-aisle airplane to replace the rather old 737. It seemed like the logical choice that would allow the manufacturer to design a far more efficient aircraft unconstrained by the 737’s old, metallic airframe and technologies. The reason Boeing might not have chosen to scrap the 737 earlier, though, is because, to airlines, fuel efficiency matters less for their short-haul planes. That’s partially just because smaller planes fly fewer hours per day. Among American airlines, for example, the average small narrow-body plane spends 8.2 hours airborne per day while the average wide-body plane spends 11.5 hours airborne. Meanwhile, though, the average small, narrow-body plane flies 4.5 flights per day whereas the average wide-body flies just 1.5 per day. Considering small planes fly shorter routes, they spend more time on the ground unloading and loading between flights. So, with fewer hours per day in the air, the proportion of cost devoted to fuel is lower to operate small planes than big planes. Traditionally, airlines would rather have a cheap, small plane rather than an expensive, super efficient small plane. The 737 is just that—it’s a cheap, small plane. The 737-700’s list price is only $89 million and, once airlines actually negotiate an order, the real price is far less. With over 50 years of experience, Boeing has perfected the 737 manufacturing process and is therefore able to offer the plane at a relatively cheap price. At their peak, Boeing was making one 737 every 14 hours. So, in summary, when prioritizing which planes to buy, airlines are going to be more focused on upgrading their long-haul, wide-body fleets to the newest, most fuel-efficient airplanes than their small planes. In the past decade or so, though, airlines have been changing how they’ve been using narrow-body planes. Planes like the 737, a320, and 757 have long been the core of almost any airlines’ short-haul fleet, but they’ve started to be used for longer and longer flights. These smaller planes are cheaper to operate and have been getting redesigned with longer and longer range which allow airlines to operate longer routes with less demand that couldn’t fill a larger, wide-body plane. The fleet age of United’s planes, for example, indicates just this. You can see that the average age of most of their narrow-body fleet is from the late 1990’s and early 2000’s while much of their wide-body fleet was put into service in the current decade. But going back to what’s changed, you can see that with small, narrow-body planes, over the past twenty years, these planes are flying fewer and fewer flights per day while being airborne for more and more hours per day meaning they’re flying longer and longer routes. In addition, in 2011, when Boeing was deciding what to do next with the 737 program, jet fuel prices had reached close to an all-time high so airlines were more concerned than ever about fuel efficiency, even for their smaller planes. Therefore, the fuel efficiency of these small, narrow-body planes was and is becoming more and more important. That, in addition to a general need to improve efficiency over time, was why Boeing was looking to create an all new narrow-body airplane. But then reality hit. On December 1, 2010, Airbus announced that it would release a re-engined, more efficient version of their A320 family aircraft—the A320neo. Unfortunately for Boeing, the A320neo sold quite well in its first few months. It was clear that airlines wanted a more efficient small plane, and fast. Soon after, something worse happened. American airlines, which was, at the time, one of the world’s largest airlines, had no Airbus planes in 2011. All of their long haul fleet and most of their short-haul fleet was built by Boeing. On July 20, 2011, though, American announced a massive order for 460 narrow-body planes—130 Airbus a320’s, 130 Airbus a320neo’s, 100 737’s, and 100 re-engined 737’s. The press release said, American, “intends to order 100 of Boeing's expected new evolution of the 737NG, with a new engine that would offer even more significant fuel-efficiency gains over today's models.” At this point, this re-engined 737 had not been announced. American announced an order for a non-existent plane. They strong-armed Boeing into re-engining their 737 rather than building a new airplane by dangling an order of this hypothetical revamped airplane over them. It’s likely that Boeing had already agreed internally to re-engine the plane but nonetheless, why would American do that? Why would they want a less efficient, less modern re-engined 737 over a more modern, more efficient brand new narrow-body plane? Well, in short, it’s because fuel cost is far from all the cost. Pilots are generally trained to operate just one type of aircraft. Some fly the a380, some fly the 777, some fly the a320, and some fly the 737, but they don’t fly the 737-700 or 737-800 or 737-900, they fly the 737 airplane as a whole. Pilots are trained to the aircraft, not the specific aircraft variant. In general, pilots can and do switch between variants of aircraft even in any given day and are not required to do any substantial training to be certified on different aircraft variants. Crucially, the FAA has never required that 737 pilots complete any simulator training before flying new 737 variants. That’s because a 50 year-old 737 more or less flies like a 1 year-old 737. American wanted a refreshed 737 over a new plane since they already had thousands of trained and certified 737 pilots. They had no pilots for a hypothetical new narrow-body Boeing and the cost of training their pilots to a new plane would be massive. Even ignoring the training costs, though, it’s far cheaper for airlines to just have one large fleet of one type of aircraft rather than a few smaller fleets of different aircraft. That’s why budget airlines like Ryanair, EasyJet, and Southwest each operate only one aircraft type. It costs less to just have one group of pilots and mechanics that can work on all the planes and that’s why most airlines try to have as few different aircraft types as possible. So, soon after American’s order announcement, Boeing officially announced the 737 MAX. This aircraft would be 15% more fuel efficient than the previous 737 model and would therefore have a maximum range of 4,400 miles or 7,100 kilometers compared to the old 737’s 3,400 mile or 5,400 kilometer range. This would make it easily possible to operate transatlantic flights on this small, narrow-body plane. Airlines did end up taking advantage of this range to operate long, yet low-demand routes. For example, Air Canada operated transatlantic flights from Halifax and St. John’s to London Heathrow using the 737 MAX. Norwegian Airlines flew them as far as Newburgh, New York to Bergen, Norway. Gol Airlines, meanwhile, broke records with their daily 737 MAX flight all the way from Brasilia, Brazil to Miami, Florida—an up to eight hour flight. To achieve the fuel efficiency and range improvement that made these flights possible, though, Boeing had to make a crucial change to the aircraft. They had to fit bigger engines. Without getting too much into the engineering, the newest, most efficient engines are all physically larger than those of the past due to designs that have more air bypass and flow past the engine core. The problem, though, was that the 737 design was quite low to the ground. Back 50 years ago, when the aircraft was designed, this was a conscious choice. It was a feature that made it easy to load bags without a conveyor belt and maintain engines without a lift. This simplified operating to many of the less developed airports of that time. This proximity to ground was no problem for the first generation of 737 that had long and thin engines that looked like this. For the second generation, though, the 737 Classic, Boeing moved the engine further forward and up and designed its intake as non-circular to achieve more ground clearance. The next generation also kept this design, but then for the 737 MAX, they just had to fit an even larger engine. So, they put it even further forward and up in addition to adding 8 inches or 20 centimeters to the nose-gear. These changes, though, changed the aerodynamics of the plane and therefore how it handled. It would cause the plane to pitch up more than the last generation which would put it at a greater risk of stalling. So, they installed a system called MCAS—the Maneuvering Characteristics Augmentation System. This system would activate when it sensed the aircraft’s angle of attack was too high and would automatically rotate the horizontal stabilizer to cause the aircraft’s nose to pitch down. The aircraft figures out its angle of attack, though, through a sensor and if this sensor is broken, it can cause the aircraft to think it is flying at too high of an angle and self-correct. Unless the system is deactivated, it can keep pitching the aircraft down until the ground. It is this that is believed to have been the cause of the crash of Lion Air Flight 610 in October, 2018 and the crash of Ethiopian Airlines Flight 302 in March, 2019 and it is these that led to the grounding of every single 737 MAX in the world. Boeing found itself, back in 2011, in a position where it had to choose between the easy wrong or the difficult right. It had to choose between short-term and long-term gain and it chose to win now. It chose to push the limits of an old design to a point where it required correction upon correction to even make it the same plane. Given the storm of economic pressures surrounding the company in 2011, though, Boeing’s investors would not have been happy if the company had embarked on a long, expensive new aircraft design process while Airbus engulfed market share with their A320neo. Nobody would have guessed at the time, with the company and aircraft’s phenomenal safety record, that that decision would lead to a potentially faulty plane. Nobody would have guessed that the decision would potentially cost hundreds of lives. It was a hasty decision made by hasty human brains and for that, Boeing and its 737 program will suffer long-term, possibly permanent consequences. I’ve just re-done the Wendover Productions website with Wix which was a great, simple, and quick process. One of the things I like about Wix is that they have a few different ways you can make your site depending on your experience level and how much time you want to take. You can have them make it for you using their artificial design intelligence, you can make it yourself using the Wix editor, or for the experienced, you can code your website easily with a bunch of extra features using their Corvid system. Personally, I used the Wix editor and was able to quickly make a site that I think looks quite good. Their designer templates and drag-and-drop website builder made it quite easy. Wix’s paid plans are all quite reasonably priced and even include a custom domain name but, you can start building your website today for free at wix.com/go/wendover.
Info
Channel: Wendover Productions
Views: 1,711,809
Rating: 4.8870201 out of 5
Keywords: 737 max, 737 max 8, 737 max 9, 737 max 10, boeing, airbus, airplane, aviation, airports, aircraft, faulty, problem, what made the 737 max crash, 737 max grounding, wendover productions, animated, explainer, documentary, video essay, economics, explained, interesting
Id: BfNEOfEGe3I
Channel Id: undefined
Length: 12min 37sec (757 seconds)
Published: Tue Apr 30 2019
Reddit Comments

The thing is.... Adding larger engines isn't inherrently a problem. And neither is MCAS, if it was designed right.

But Boeing completely bodged it. They bodged, the bodge even.. And that's why it's as dangerous as it is.

Redundant angle of attack sensors, and then maybe some other form of sensor which can measure the tilt of the plane would have likely made the chance of a failure of the MCAS system near zero.

Or at least have the MCAS system automatically cut off if two sensors read vastly different readings.

So many things could have been done, but weren't.

It's mad.

👍︎︎ 31 👤︎︎ u/PepperUrAngus 📅︎︎ May 01 2019 🗫︎ replies

I for one am shocked that corporations would place profit over relative safety and technological advancement.

Paper checklists and dummy lights, nice.

👍︎︎ 197 👤︎︎ u/Mmedical 📅︎︎ May 01 2019 🗫︎ replies

Here's a reconstruction of the cockpit situation in the accidents, based on reports available to the public at this time:

  • AoA sensor on ET302 had a physical malfunction.
  • Wrong AoA reading on JT610 might be caused by physical or electronic issue.
  • The Mcas software has no safety and redundancy checks. This is a basic design principle, every flight control software is designed with such measures. Ignoring this principle resulted in the Mcas giving commands to the stabilizer that brought the ET302 to a nose-dive from level flight in 10 seconds. On JT610 level flight to nose-dive happened in 30 seconds.
  • The Mcas operates the stabilizer in 2.5 degrees / 10 second bursts, 4 times faster than the Speed Trim System known to the pilots from the 737 NG.
  • Mcas can't be disabled on its own. Two "Stab Trim Cutout" switches between the pilots disable the trim motor (both of them), also disabling the pilot's ability to electrically trim. In comparison the 737 NG has separate switches for the pilot's trim and the automatic trim (AP/STS).
  • Pulling back on the yoke (the instinctual reaction) stops a Runaway Trim in case of the 737 NG, but the Mcas overrides this safety switch. This safety protects from an out-of-trim situation where the elevator and the stabilizer works against each other, causing the trim jackscrew to jam, as happened on ET302.
  • The accident planes had flight control issues, stick-shaker, airspeed and altitude disagree warnings right after takeoff, minute(s) before Mcas activated. A very intense environment.
  • On JT610 the pilot continuously corrected the Mcas actions by long 5-10 second trim inputs. In the last 80 seconds the inputs are shorter, only 2-4 seconds. Just 30 seconds before the crash the plane was flying level.
  • ET302 was at take-off thrust (94%) through-out the whole flight, gradually getting faster. There was no reaction to the over-speed warnings, but the Master Caution warning was called out.
  • ET302 was flying erratically with oscillations in all 3 axes after auto-pilot was turned on. The plane was going up and down in 3 second periods. After Mcas activation the trim went from 4.6 to 0.4 units. While it was being corrected the motor has been disabled (40 seconds after Mcas activation), the trim stopped at 2.1 units, halfway to the original climb setting. The CVR recorded the copilot saying "trim cutout", the pilot agreeing and the copilot confirming. The following Mcas command was ineffective, confirming the cutout took place.
  • After trim cut-out moving the trim wheels by hand (hand-cranking) failed as the aerodynamic forces jammed the elevator jack-screw. The jamming issue was know and a recovery procedure published in the classic 737-200's manual called the "Roller-Coaster". This procedure is missing from current manuals, and dangerous at low altitudes.
  • The Boeing published Runaway Trim procedure and the Emergency Airworthiness Directive published after Lion Air crash. Expects the trim wheels to move freely. A trim lockup failure mode is not mentioned, there is no instruction for a situation when trimming is not possible.
  • The state of the trim cutout is not recorded in the FDR and the pilots did not say or agree to re-enable the trim, thus it is an unconfirmed, but likely scenario that the trim was re-enabled at the end of the flight. Only two momentary trim inputs are recorded by the FDR, inconsistent with earlier 5-10 second inputs and completely irrational. 5 seconds later Mcas activates, 10 seconds later the airplane is in a nose-dive.

Don't believe everything written on reddit, do your own research:

Reconstruction of events: Even Without Answers, The Data Tells a Story - analysis

Videos about the accident:

The 737 Max is a 50 years old plane: The Economics That Made Boeing Build the 737 Max - 12 min video
Accident summary: Vox video - The real reason Boeing's new plane crashed twice - 6 min

Some technical articles and videos by professionals:

Illustration of the trim issue - 13 min read with images
Simulator demonstration of the difficulty to trim the 737 by hand when severely out-of-trim
AoA Sensor disassembly (different type) - AvE - 20 min video

In-depth analysis of the preliminary report - article, diagrams
How the Boeing 737 Max Disaster Looks to a Software Developer - long article
737: The MAX Mess - very long read for the curious kind, with all the nasty details, whispers and reading along the lines
Pilot's explanation of the Preliminary Accident Report - 24 min video
Whistle-blower documentary - The Boeing 787: Broken Dreams - 1h video

Technical details:

What happened on ET302? - Aviation engineer's analysis, multiple articles.
Trim Cutout with Severe Out-of-Trim Stabilizer can be difficult to recover
Differences between the 737 MAX and the NG - the MCAS

Official reports:

Ethiopian Airlines ET302 preliminary report (pdf)
Lion Air JT610 preliminary report (pdf)

Investigation updates:

Avherald: Ethiopian B38M (ET302)
Avherald: Lion B38M (JT610)

👍︎︎ 43 👤︎︎ u/Mongusius 📅︎︎ May 01 2019 🗫︎ replies

They will pay dearly for it.

They might be winning the public perception but anyone that is in aviation (the people buying planes) know what a shit show it is and won’t be buying Boeing anytime soon.

👍︎︎ 20 👤︎︎ u/Jesta23 📅︎︎ May 01 2019 🗫︎ replies

Edit: merged with duplicate comment above

👍︎︎ 8 👤︎︎ u/Mongusius 📅︎︎ May 01 2019 🗫︎ replies

My understanding is Boeing had to make this a "type" aircraft so no additional simulator time was required otherwise it would not compete with the A320 NEO. When they moved the engines forward and up they changed the flight characteristics of the aircraft which required more training as did dual AOA sensors. It's a huge mess. I'm a pilot with an airframe inspection rating and I don't think I'd fly in this 50 yo plane

👍︎︎ 2 👤︎︎ u/john0412 📅︎︎ May 08 2019 🗫︎ replies

seems unfair to chastise boeing's decision to go the rout of revamping the old model, when the actual problem was the MCAS or not having enough redundancy in the sensor.

👍︎︎ 20 👤︎︎ u/oomio10 📅︎︎ May 01 2019 🗫︎ replies

Well, Seattle wouldn't be quite as fucked as they might have been 20 years ago thanks to the tech boom, but if this sinks Boeing, a LOT of engineers and people in the Everett/Tacoma/Seattle area are going to be out of work. Boeing is such an important part of Seattle and Washington's economy that I wouldn't be surprised if they end up with some sort of bailout like the car industry got. Boeing going under could sink Seattle's economy for a decade. BUT, real-estate might get a littler cheaper (HAHAHA, no) and I guarantee some of those unemployed engineers would think about making a new company and we could potentially see a brand new player in the aircraft world.

👍︎︎ 3 👤︎︎ u/GreasyPeter 📅︎︎ May 02 2019 🗫︎ replies

It's based on earlier 737 designs but it was introduced in 2011. It's not the same as a 737 as it has different engines, as well as numerous other design changes including structural. You can't just take a regular 737 and turn it into a 737 max. There's a lot of work that needs to be done which is why it's built entirely new, not by taking old planes and retrofitting them.

👍︎︎ 3 👤︎︎ u/SC2sam 📅︎︎ May 01 2019 🗫︎ replies
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