
A 50-year-old design came back to haunt Boeing with its troubled 737 Max jet - eplanit
https://www.latimes.com/local/california/la-fi-boeing-max-design-20190315-story.html
======
nabla9
Boeing want's to keep the type rating and rest of the infrastructure, but the
airframe is getting old. They made a small tweak, moved engines forward, and
gained significant fuel savings. The tweak caused instability. The fixed it
with automation that introduced complication.

Type ratings, airport dimensions, etc. create legacy that puts limit to what
kind of aircraft designs are economically viable. If you could start from the
scratch and design new aircraft and airports in tandem , would probably have
much wider wingspans and lifting bodies. Airports would need different design
to move passengers and arrange aircraft.

~~~
lstodd
The airframe isn't getting old. In fact there's nothing left of the old
airframe but the general shape of the windshields.

It's the type rating approval process that got old and caused all this.

~~~
the_mitsuhiko
How exactly is the approval process at fault here? Nobody forced Boeing to
make a plane that has the same type rating.

~~~
BurningFrog
It would cost some number of $B and years to get different type rating.

If you want to call that "forcing" is a matter of taste, but it's certainly a
very strong and involuntary incentive.

~~~
ctvo
Boeing made the decision to maximize profits by retrofitting an older model.
There’s nothing involuntary about it.

They’ve released newer model planes that have gone through the review process
fine, correct?

~~~
js2
FWIW, according to Wikipedia Boeing had intended to design a new plane but
were forced into re-engineing the 737 by market forces:

> In 2006, Boeing started considering the replacement of the 737 with a
> "clean-sheet" design that could follow the Boeing 787 Dreamliner.[12] In
> June 2010, a decision on this replacement was postponed into 2011.[13]

> On December 1, 2010, Boeing's competitor, Airbus, launched the Airbus
> A320neo family to improve fuel burn and operating efficiency with new
> engines: the CFM International LEAP and Pratt & Whitney PW1000G.[14] In
> February 2011, Boeing's CEO Jim McNerney maintained "We're going to do a new
> airplane."[15] At the March 2011 ISTAT conference, BCA President James
> Albaugh was not sure about a 737 re-engine, like Boeing CFO James A. Bell
> stated at the JP Morgan Aviation, Transportation and Defense conference the
> same month.[16] The A320neo gathered 667 commitments at the June 2011 Paris
> Air Show for a backlog of 1,029 units since its launch, setting an order
> record for a new commercial airliner.[17]

> On July 20, 2011, American Airlines announced an order for 460 narrowbody
> jets including 130 A320ceos and 130 A320neos, and intended to order 100 re-
> engined 737s with CFM LEAPs, pending Boeing confirmation.[18] The order
> broke Boeing's monopoly with the airline and forced Boeing into a re-engined
> 737.

[https://en.wikipedia.org/wiki/Boeing_737_MAX#Background](https://en.wikipedia.org/wiki/Boeing_737_MAX#Background)

------
InTheArena
Really it's worse then that. The 737Max is a good example of technical debt.
The plane more or less is the same fuselage as a Boeing 707 (with material
modernized). Boeing went back to the well one time too many instead of doing a
cleanroom design for it's narrow-body fleet.

Boeing has hinted several times that they want to look at a Blended Wing Body
(BWB) design for the next generation of planes. That time may be now.

~~~
CydeWeys
It's hard to think of many other legacy systems that have been around since at
least the 60s like the 737 MAX has. The NYC subway system is one that
immediately comes to mind.

~~~
Someone1234
The engines on many light single-engine aircraft (e.g. Lycoming O-360). While
variants and modest improvements have been made, it is still the same 1950s
engine at the core.

Safety requirements have evolved massively since then, but if you keep making
the same engine with modest changes it can grandfathered. Kind of makes you
wonder if grandfathering should have a limit (e.g. 50 years?).

~~~
a1369209993
> Kind of makes you wonder if grandfathering should have a limit (e.g. 50
> years?).

That's not grandfathering. Grandfathering is "This engine was built before we
made the law, so you can keep using it until it breaks."; what you're
describing is just blatant selective enforcement.

~~~
Scoundreller
What’s it called when the thing was designed before the law, and therefore
allowed to be manufactured for eternity?

~~~
a1369209993
"Criminally[0] negligent duty-derelictive non-enforcement of safely
regulations"?

0: or not-technically-criminally if they planned ahead well enough.

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mrpippy
For those who might be interested: the 737 type certificate data sheet.
Revised 64 times since 1967 and covering original, Classic, NG, and MAX.

[http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeMod...](http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/179cdacd213801658625832a006b2e37/$FILE/A16WE_Rev_64.pdf)

------
js2
I would be interested in an organizational investigation of Boeing, the FAA
and the airlines similar to the investigation of NASA after the Challenger
disaster.

I keep reading comments that it was just corporate greed or just regulatory
capture or Boeing should’ve just built a new plane. But I suspect it’s not
that simple, and that there are lessons to be learned beyond what the crash
investigations uncover.

For example, from reading the Wikipedia on the 737 Max it sounds like Boeing
was pressured by the airlines into producing the Max after Airbus was able to
ship a more fuel efficient 320.

Usually you expect competition to lead to better products so it would be
somewhat ironic if the competition from Airbus is what forced Boeing’s hand on
producing the Max. Without that pressure maybe Boeing could have told the
airlines to back off while it produced a new design.

~~~
pducks32
I’m no airplane expert but I find the trend lines of the industry interesting
and one trend has been how fuel prices and long lead times on fuel efficiency
has lead to formerly continental planes now flying intercontinental. AirBus
has really done this well and airlines love to be able to reuse resources.
With the MAX there is a sense that airline execs are spooked by a new plane
since it requires a ton of new training and maintenance outfitting. So Boeing,
possibly smartly, tried to create what these airlines would pay for (a fuel
efficient airplane) that would marketable be super similar to a very popular
plane. But this lead to rushing the process and making too many affordances
and hiding the differences from airlines and training material for fear of
spooking business execs worried about cost.

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PaulHoule
The 737 is not uncomfortable because it is narrow but because it is not tall
enough. The circular fuselage makes it so.

The much smaller Embraer 195 is vastly more comfortable than the 737 because
it is shaped according to the passengers.

A clean sheet design for the 737 would have a big positive impact for the
industry. Today it is another reason to take the bus.

------
gargalatas
"The change, however, affected the plane’s aerodynamics. Boeing discovered the
new position of the engines increased the lift of the aircraft, creating a
tendency for the nose to pitch up."

The problem wasn't just the ground clearance. the problem was that
aerodynamically had issues (not so well balanced probably). So when they were
trying to fix "this" something else was breaking and so on. That's why they
introduced this MCAS software in the first place. It wasn't some new fancy
tech but it was just a system to help with the bad 737's aerodynamics.

~~~
iguy
Right, but it sound like the aerodynamics have been deteriorating model-by-
model, as they move away from the original design.

This creeping change must be really hard to regulate right. A terrible new
design you could refuse to certify, but a terrible one which is only a few
percent worse than the one your predecessor certified a decade ago... it would
take a lot of confidence to say no.

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basicplus2
<Boeing added larger, more powerful engines, but that required it to
reposition them to maintain ground clearance. As a result, the 737 can pitch
up under certain circumstances.>

This has to be THE MOST Stupidest decision i have ever read about.. either
extend the landing gear or start from scratch.

Aeroplanes should be naturally neutral Longitudinally and also have
longitudinal static stability it should never require complex control systems
to achieve any of this.

It should never have passed certification.

[https://en.m.wikipedia.org/wiki/Longitudinal_static_stabilit...](https://en.m.wikipedia.org/wiki/Longitudinal_static_stability)

~~~
lutorm
"Under certain circumstances" is, as I understand it, close to stall. Many
planes have less-than-desired stall characteristics. The tendency of T-tail
planes to go into an unrecoverable deep stall comes to mind.

Or have you ever flown a Cessna 152 or 172? They have the same tendency to
pitch up strongly when power is advanced at low speeds. This is probably the
most common training aircraft in the world, and yet have a behavior that may
cause them to stall at exactly the most inopportune time. And they're flown by
students, not airline transport pilots!

The 737 MAX does not _require_ the MCAS. The pilots could be trained to expect
and handle this characteristic. (And they are, as it is apparently, to a
lesser degree, present on all 737 models.)

The big problem lies in the design of the MCAS system and the fact that it was
decided to rely on this and not train pilots on the new behavior.

~~~
basicplus2
putting and engine on the wing in an undesirable position because of the
height of the landing gear is stupid..

just because "a pilot should be able to handle it" is not acceptable.

Aeroplanes traditionally are designed with as much passive self correcting
features as possible for safety.

When a plane has a real emergency the less a pilot has to actively deal with
the more likely people are going to come out alive.

The evidence is clear that this was a huge mistake.. many people have already
died.

------
etep
It's not nice that so many writers parrot that the solution is "more pilot
training." Under the hypothesis that there needs to be a solution (one that I
think is correct), then the answer of more training amounts to mere hope. One
hopes that the pilot a) knows and b) remembers to turn off the autopilot when
the emergency starts.

~~~
SomeHacker44
Pilots can fly planes with unusual characteristics when properly trained. That
is the point of the type rating. I feel the 737 MAX needs its own type
certificate distinct from the rest of the 737s and that should solve the
problem, since the MAX has very different flight characteristics in certain
situations.

Either that or ground the plane permanently for being poorly designed and
unsafe with any amount of training.

If the FAA does anything else, it will harm my faith in the organization,
which is already at a recent low.

NB: Jet pilot, not 737 pilot.

~~~
lutorm
737 pilots have said that they are already trained in the tendency of a 737 to
pitch up when full power is applied at low speeds, which apparently is present
in all 737 models. (Stall recovery procedures for a 737 apparently
specifically detail that you must lower the nose _first_ , and then apply
power (and not too much power) as applying full or higher power near stall
speed will overwhelm the pitch authority.

What's not clear to me is how much worse the characteristics of the MAX are
compared to the NG or earlier 737s? Would it really be unsafe to fly without
the MCAS, or was this just the route Boeing took to avoid having to retrain
pilots?

~~~
WrtCdEvrydy
Money's on a last minute fix to the problem and engineering being told the
launch couldn't be delayed.

------
crimsonalucard
They should have a philosophy of building aerodynamically stable aircraft
rather than relying on software and sensors to produce an illusion of
stability.

~~~
WalterBright
Consider that before WW2, pilots had direct connection between the control and
moving the surface. After WW2, planes got too big and heavy for that, and
hydraulic boost was added. Starting with the 747, where it is not credible a
pilot could control it with muscle, the switch was made to fully powered
surfaces.

The trouble with that is the pilot's controls simply crack open a valve, and
hydraulics do the rest, meaning the pilot gets no feedback via forces on the
control column. He'll "overcontrol" the aircraft leading to a crash. The
solution is the addition of a "feel computer" which pushes back on the stick
making the airplane feel like direct control. Safe flying relies on the feel
computer working properly.

Also, the travel of the control surfaces is automatically reduced as speed
goes up, because full travel at high speeds will literally tear the airplane
apart.

So right there are two flight critical computer systems on jets, and modern
air travel would not be possible without them. Each produces an illusion to
the pilot.

~~~
crimsonalucard
Right, this makes sense. The system you describe magnifies or reduces the
signals going back and forth between the pilot and the control surfaces. It
can be modelled linearly and done with an analog system.

However I'm referring to a computer literally trying to hide a stall that
occurs when you pitch the nose up by producing an inverse signal out of thin
air that has no input from the pilot. Why wasn't this needed before the max
moniker was added to the plane?

Seriously, build the plane so that this doesn't happen. Don't create some MCAS
system to hide it.

~~~
WalterBright
MCAS was there to prevent a stall, not hide it. All airplanes will stall under
varying circumstances. Much of pilot training goes towards avoiding and
recovering from stalls, but they still result in crashes.

~~~
crimsonalucard
The stall didn't exist at that configuration previously. MCAS prevents the
pilot from even knowing about this stall by preventing the plane from even
going into that configuration. In other words it hides the stall by preventing
you from maneuvering the plane into it. It fits the definition of "Hide." But
that's besides the point, we're arguing about semantics here.

I'm saying similar to the older design make the aerodynamic shape good enough
so that it won't hit that stall when the plane is flying at that same
configuration. I'm also saying that the control system should only magnify or
reduce the signals the pilot sends to the control surfaces rather than
actually sending it's own override signals itself. That's it... pure and
simple.

~~~
speedplane
> MCAS prevents the pilot from even knowing about this stall by preventing the
> plane from even going into that configuration. In other words it hides the
> stall ...[.] [T]he control system should only magnify or reduce the signals
> the pilot sends to the control surfaces rather than actually sending it's
> own.

What about fly-by-wire? Many aerodynamic controls are assisted by avionics,
and have been for decades. The MCAS system is not fundamentally different. The
intent of the system was to put the plane where the pilot wanted intended it
to go, similar to how a fly-by-wire system will keep a plane flying straight
if a pilot doesn't touch the yoke.

The problem seems to be that the MCAS system breaks under certain conditions,
however the fundamental idea is sound. Planes have been doing similar control
adjustments for decades.

~~~
crimsonalucard
No its not. Fighter planes like the F-16 are designed to be aerodynamically
unstable for higher maneuverability. For this case an incredibly fast control
system is required to make minor adjustments to the plane to maintain
stability. This control system is in constant control of the plane and the
entire jet aircraft is designed to operate in such a way.

The 737 MAX was made more aerodynamically unstable then the original 737. A
partial control system was put in place to hide this instability should the
pilot maneuver the plane into the configuration that will trigger a stall.
It's an entirely different situation than the jet plane above.

Think of it like a bandaid to cover up a problem. I'm saying don't use
bandaids. Design the plane correctly from the ground up.

~~~
speedplane
> A partial control system was put in place to hide this instability should
> the pilot maneuver ... It's an entirely different situation than the jet
> plane above.

I wasn't talking about military craft, I was referring to commercial aircraft
that also have fly-by-wire capabilities, of which there are plenty of
examples.[1] The MCAS is not fundamentally different from these other existing
systems.

[1] [https://en.wikipedia.org/wiki/Fly-by-
wire#Airbus/Boeing](https://en.wikipedia.org/wiki/Fly-by-wire#Airbus/Boeing)

~~~
crimsonalucard
Right, except military aircraft is where FBW was developed and very very much
_required_ for performance. Such is not the case for passenger airliners. Only
two Boeing planes use FBW, the 777 and 787. Every other plane does not use it
including the 737.

The MCAS is fundamentally different in that it is a partial FBW system that
they tacked on on top of an existing control scheme that is not FBW.

It's a random partial FBW component grafted onto something that's completely
different. Sort of like a mod chip in a console. It's a hack. To drive home
the exact opposite of what you said: "MCAS is abnormal and fundamentally
different from many existing systems."

------
baybal2
And one more thing - trim tabs should be separate airfoils, not an
electronically set setting exactly for the purpose of reliability.

That way, an elevator should always have more authority than the trim tab, and
be able to overpower it if it fails.

On other hand, independent trim tabs can work as reserve control surfaces if
hydraulics fail.

The same design thinking is behind having engine reverse locks being physical
parts, separately powered, and operated independently of electronic engine
controls: a hard lock will always be able to overpower haywire electronics.

Same with emergency chassis deployment system on smaller planes, they are
often designed to be able to physically disconnect/overpower motors that pull
chassis, or chassis cowers if they jam or electronics bugs out.

~~~
CarVac
Trim would never be a separate airfoil because that would be horrendous for
efficiency. Instead they have an all-moving tailplane.

They could have prevented this issue by slightly increasing the tailplane size
to restore stability margin, but they didn't presumably for development cost
and fuel efficiency reasons.

~~~
baybal2
Are you really sure that it will be "horrendous?"

That thinking remind me of people who try to economise on few microns of
plastic we see in electronics OEM industry. Pro managers trying to shave
microns from casing, ending up with multimillion dollar recalls, and that for
savings not even amounting to few snickers bars.

~~~
CydeWeys
You're adding an entire new system. That's more wiring, more programming, more
hydraulics, more moving parts, etc. It's far from trivial.

~~~
baybal2
Far from trivial, but it was done in the past nevertheless. All things above
were going away one after another, and replaced with often ineffectual
electronic safeguards.

------
cmurf
Any design will have consequences, and is thus relevant. But changing it has
as much of a consequence as not changing it. Example: Airbus design has
"stick" type yokes that are not linked together, and are out of the field of
view. If one pilot is using improper inputs, the other pilot won't know.
Boeing planes have mechanically connected yokes, both pilots are aware of
flight control inputs. Is one a better design than the other? I suggest it's
the wrong question, the right question is, what are the consequences of the
design on cockpit communication, management, and training and can we meet the
ensuing requirements?

------
upofadown
The calls for more and better training make me wonder why we don't just train
for the relatively rare over pitch characteristic that the MCAS system is
intended to prevent. If we can't actually train for that then why are we
suggesting that the solution is just being quick to turn the system off? What
level of unreliability is required to make it better to just never turn it on?

------
danny8000
I wonder why Boeing didn’t they design new, longer landing gear instead of
moving the engines forward?

Then the engines could have remained in the same position. I am sure most
airports could handle a taller airplane.

~~~
Moto7451
Not a direct answer, but what you’re more or less asking is “why did they not
modernize the 757 instead?” The answer is type ratings. Pilots can fly certain
classes of planes based on common training. I.E. the 757 and 767 are common
enough you can be trained for both at the same time. The issue with changing
geometry of the 737 is you have to then retrain pilots against a new type
instead of letting them take an orientation course on the new plane.

Honestly if the accidents did not happen we’d be calling them geniuses. After
all, that’s why the 737 is the best selling plane ever.

~~~
ardy42
> Not a direct answer, but what you’re more or less asking is “why did they
> not modernize the 757 instead?” The answer is type ratings.

But if there's already an existing type out there that's a better fit, why not
just use that?

~~~
selectodude
Because the plane was basically designed for Southwest Airlines and American
Airlines, and they demanded a new 737, not a new plane.

~~~
FPGAhacker
“If I had asked people what they wanted, they would have said faster horses.”
-- Henry Ford (purportedly)

~~~
nradov
There is still a significant niche market for faster horses.

------
Invictus0
Does anyone know why Tunisia refused to work with the FAA?

------
woodandsteel
"First introduced in West Germany as a short-hop commuter jet in the early
Cold War"

The Cold War started in the second half of the 1940's, so I rather doubt that
is true.

------
burtonator
My family would have flown on a 737 Max this morning. Flight was cancelled.
The FAA was literally the last regulatory org to ground the 737 Max... I'm
livid that corruption and bias put my family at risk!

~~~
crimsonalucard
Yeah. It is strange that they were the last regulatory org to do so. . In
America basically every governmental body is in the pocket of big business.

~~~
ardy42
This is an interesting take on it:
[https://www.nytimes.com/2019/03/15/opinion/federal-
aviation-...](https://www.nytimes.com/2019/03/15/opinion/federal-aviation-
administration-boeing.html).

Basically, the US has taken the view that any regulation should be strongly
supported by facts and evidence, while many other countries are more willing
to regulate on a precautionary basis, before all the results are in.

~~~
crimsonalucard
A speculative opinion piece. Here is another one: [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)

Two planes of the same model crashing of is a statistical anomaly. Science is
the correlation of hypothesis with statistical evidence. If I made a
hypothesis saying that something is wrong with the 737 max then two 737 planes
crashing is valid supporting evidence. Therefore, the decision to regulate is
scientific.

The decision to not regulate and claim that there is no scientific evidence
when their clearly is... is more likely to be a cover story to protect big
businesses then an actual decision made to support your safety.

