
Prosecutors, Transportation Department Scrutinize Development of Boeing 737 Max - mehrdadn
https://www.wsj.com/articles/faas-737-max-approval-is-probed-11552868400
======
virgakwolfw
Why is MCAS needed? If the MAX is so similar to old 737’s and no additional
training is needed, then why the MCAS? The most relevant question is “is the
MAX aerodynamically stable?” If it is, why do we need the MCAS? That needs to
be investigated.

If plane at a low altitude at full power is stalling, just lower the nose.
That is pilot training 101. Why need a system like MCAS to help. The pilot
should be able to disengage the autopilot and take control of the airplane.
This should be simple.

My suspicion is that there is an inherent, more fundamental problem with the
MAX. Before Boeing rushes a software fix, idependendent entities “(remember we
can no longer assume the FAA is independent based on what transpired over the
last few days) need to investigate and makes sure the plane is safe.

I for one will not fly the MAX regardless of what the FAA and Boeing say.
Their reputation for prudence and safety is gone.

~~~
VBprogrammer
> Why is MCAS needed? If the MAX is so similar to old 737’s and no additional
> training is needed, then why the MCAS? The most relevant question is “is the
> MAX aerodynamically stable?” If it is, why do we need the MCAS? That needs
> to be investigated.

This isn't even a question. The 737 Max is completely aerodynamically stable.
It does however exhibit control behaviours which are undesirable.

A fair analogy for this is probably a car which oversteers, in general a
normal family car is designed to understeer, because for your average driver
that is safer. In the 737 Max the controls get lighter close to the stall
because of lift generated by the engine nacelle. The certification
requirements require that the controls don't get lighter. Boeing applied what
now appears to be a poorly thought out fix.

What might surprise you is that there are plenty of certified aircraft which
are actually aerodynamically unstable, at least along the longitudinal axis.
For example the 757 has dual yaw dampers and at least one of them needs to be
serviceable before flight. The consensus is that at cruise altitude it would
depart controlled flight without one of them working.

~~~
ajnin
> The certification requirements require

Eh, let's not spin it as "the requirements made them do it", they _chose_ to
make the new model stick with the existing 737 certification because building
a substantially different new plane would require pilots to be retrained, and
they didn't want that as Airbus was ahead of them in the development of the
A320neo and they needed that commercial advantage to remain competitive.

~~~
VBprogrammer
I'm not sure where you draw the line though? None of this is new, making
modifications to existing designs is the aviation equivalent of developing a
new feature. Hanging new engines from an existing fuselage, replacing the
avionics and lengthening a fuselage have all been done before with reasonable
results. Conversely, clean sheet designs have had terrible safety records
initially.

Asking a manufacturer to make a clean sheet design every time they make a
change is probably going to result in more accidents than it fixes (see the
bathtub curve).

------
x0x0
The article didn't seem to mention this crucial detail [1]: The original
approval was based on Boeing's claim the MCAS had a max control of 0.6 degrees
of the 5 degrees possible. This later became 2.5 degrees applied repeatedly,
so 5 degrees.

The 0.6 claim meant that the MCAS system qualified for a max risk of hazardous
(people injured), not not catastrophic (ie plane loss).

FAA officials claim that: (1) the mcas shouldn't even have qualified as a
hazardous risk, and (2) they were unaware that it could fully control tail
deflection.

There are at least three decision makers that are probably in trouble: whoever
let the MCAS have a max rating of hazardous, whoever allowed the MCAS more
control, and whoever didn't notify the FAA. Hopefully management rather than
line-level engineers though, because this seems like a company failure.

[1] [https://www.seattletimes.com/business/boeing-
aerospace/faile...](https://www.seattletimes.com/business/boeing-
aerospace/failed-certification-faa-missed-safety-issues-in-the-737-max-system-
implicated-in-the-lion-air-crash/)

~~~
zkms
> The 0.6 claim meant that the MCAS system qualified for a max risk of
> hazardous (people injured), not not catastrophic (ie plane loss).

My god. So that is why they only used one AOA sensor rather than comparing
both -- and offlining MCAS if they disagree -- they thought it was DAL C
(maybe because 0.6 degrees of stab trim likely can be countered with elevator
deflection) and not DAL A.

And since there was no annunciator on the flight deck to indicate that MCAS
was kicking in, the flight crew on the incident aircraft weren't able to
diagnose the problem (since it didn't act like a traditional trim runaway) and
do the appropriate actions to disable the electric trim control before it was
too late.

Horrific.

~~~
oakmad
Well there's an option for dual AOA but neither Lion or Ethiopian took it. In
the case of AOA disagreement a light illuminates. Source
[https://twitter.com/trevorsumner/status/1106934415610073091](https://twitter.com/trevorsumner/status/1106934415610073091)
and [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/)

~~~
cjbprime
That's not quite accurate. The plane has dual AoA in either case. The option
is for AoA indicators and disagreement light.

So, the US airlines who bought the option will have a disagree light, but it's
still the case that their MCAS is only being fed by one sensor, so they could
experience the same control problems.

~~~
oakmad
That is true, here's a source [https://qz.com/1574441/a-warning-signal-that-
could-have-prev...](https://qz.com/1574441/a-warning-signal-that-could-have-
prevented-the-lion-air-crash-was-optional/)

A pet peeve is people not sourcing corrections

------
gdubs
It already looked bad for the FAA that they dragged their feet to ground the
plane. That a criminal investigation was launched a full day before they
finally grounded the Max raises even more questions. You have the whole world
grounding the plane, two _highly_ unusual, strikingly similar tragedies within
a short span of time, and a _federal investigation into the plane 's
development_, and it still takes a whole day to ground the plane?

~~~
dirkg
IIRC FAA didnt ground the plane. Trump issued an order and FAA were forced to
do it.

------
DennisP
> Boeing was toying with a new plane to replace the 737, launched in 1967, and
> had engineers working on the new plane concept. While many airlines liked
> the idea, existing 737 customers didn’t want to retrain their pilots at huge
> cost and so lobbied for an updated, more-efficient 737

> Then in 2011 Boeing learned that American Airlines, one of its best
> customers, had struck a tentative deal with Airbus for potentially hundreds
> of A320neo planes to renew its short-haul fleet.

American has 304 737s not including the Max.[0] So Boeing considered building
a whole new plane, reconsidered when 737 customers wanted to avoid retraining,
then did the Max when one of them started moving to a whole new plane anyway.
Something somewhere seems not quite thought through.

[0]
[https://en.wikipedia.org/wiki/American_Airlines_fleet#Curren...](https://en.wikipedia.org/wiki/American_Airlines_fleet#Current_fleet)

~~~
erentz
> Something somewhere seems not quite thought through.

Maybe timing was also an issue, the A320 reengine was (supposed to be) a
fairly quick program. A whole new airplane for Boeing presumably would’ve
taken a lot longer. For a lot of customers looking to replace 737s in the near
future maybe too long to wait. So

* A320neo sooner beats $NewBoeing later

* 737MAX same time beats A320neo for existing 737 operators

* 737MAX and A320neo a toss up for other scenarios

Edit: and if you’re a 737 operator waiting for a new plane is a very risky
proposition with delays, etc. It would be less risky if you’re going to have
to retrain your pilots to buy the 320.

------
jostmey
“A grand jury in Washington, D.C., issued a broad subpoena dated March 11 to
at least one person involved in the 737 MAX’s development...”

Given how cozy Boeing is with the US government, I fear that it will be the
engineers and lower managers who are nailed to the wall, not Boeing’s
leadership

~~~
bilbo0s
It's not like software development.

In fields like aviation and medical software, when engineers say something is
done, there are usually documents to be signed.

Right now, I don't think I'd like to be the guys who signed off on anything at
all to do with MCAS or AoA indicators. I suspect very strongly that we won't
find the CEO's signature on those documents. I always implore engineers in FDA
regulated medical software and any engineers in aviation to please, please,
PLEASE think more like engineers who build bridges and skyscrapers. When
you're signing those documents, please understand that it's legally binding.
Never let a higher up pressure you into signing such a document if you have
any reservations at all.

~~~
KineticLensman
> In fields like aviation and medical software, when engineers say something
> is done, there are usually documents to be signed

Yes. In aviation, an engineer may have a formal role as a design authority or
as a signatory on a safety case. They will typically have to themselves sign a
letter, from an engineering director, that signals acceptance of this
delegated responsibility. Most companies will have some way of matching the
magnitude of the responsibility to the experience level of the engineer. And
enlightened companies will have a no-fault 'stop-work' mechanism that pushes
sign-off responsibility upward if engineers cannot in all conscience sign off
something that they consider to be poorly designed or high risk.

------
peteretep
If there’s any truth at all to the idea that Boeing applied inappropriate
pressure, at any point, via any means, I’d like to see the rest of the world
push back very heavily on Boeing imports

~~~
growlist
Indeed, this is the type of thing US regulators love to hammer non-US
companies with.

------
sschueller
Sadly even if foul play is found at Boeing I doubt anyone will be held
accountable. The Government is full of ex Boeing people even the Secretary of
Defense is a 30 year Boeing vet.

------
JustSomeNobody
> A Boeing spokesman didn’t respond to a request for comment about the
> inspector general’s probe. Earlier, a Boeing spokesman said: “The 737 MAX
> was certified in accordance with the identical FAA requirements and
> processes that have governed certification of all previous new airplanes and
> derivatives. The FAA considered the final configuration and operating
> parameters of MCAS during MAX certification, and concluded that it met all
> certification and regulatory requirements.”

But Bloomberg has an article[0] where the FAA basically handed over much of
the process to Boeing. So, of course it was certified in accordance with FAA
requirements!

[0] [https://www.bloomberg.com/news/articles/2019-03-18/boeing-
dr...](https://www.bloomberg.com/news/articles/2019-03-18/boeing-drops-as-
role-in-vetting-its-own-jets-comes-under-fire-jtecyagp?srnd=premium)

------
dirkg
The simple fact is that if either of these were true -

\- a US airline was involved in the accident, esp on US soil \- a non-US
company was the manufacturer

then the FAA would've grounded the plane almost immediately instead of
publicly declaring it was safe, which was obvious nonsense. In addition, US
media made fun of other countries for grounding the plane.

The whole thing just shows how biased FAA/US govt has been.

------
rangersanger
I’m trying to recall some of the more recent air accidents and the resultant
investigations. I don’t remember getting blow by blow updates to the ongoing
investigation. Is this new?

~~~
MS90
The scenarios are a bit different, but MH370 dominated the news cycle for what
seemed like an eternity...

------
exabrial
I think the FAA already has a healthy culture of failure analysis that makes
is _actually safe_, not just a feel good safe. I don't want to see a bunch of
malicious prosecutors and lawyers get involved.

~~~
bilbo0s
In fairness to the Administration here, that "healthy culture of failure
analysis" always included the threat of "malicious prosecutors and lawyers".
Places like the FAA and the FDA just never put the threat of prison out front
and center.

Unless they have to.

I'm not certain this is one of those times, we need more information. But
throwing people in prison is very much the appropriate thing to do in certain
circumstances.

