
Long Before Boeing 737 Max Crash, Ethiopian Air Pilot Warned of Dangers - pseudolus
https://www.bloomberg.com/news/articles/2019-05-29/long-before-crash-ethiopian-air-pilot-warned-bosses-of-dangers
======
tomglynch
Sorry for another comment, but in my research into the topic the saddest bit
of information I've seen is the image of the black box data for the flight
(the first crash):
[https://i.imgur.com/WJuhjlO.png](https://i.imgur.com/WJuhjlO.png)

You can see from the graph that in the final minutes and seconds, the pilot
put insane amounts of force on the control column (aka the yoke) to try to
pull the plane out of the dive - to save the 189 people on board. But no, MCAS
was overpowering and lacked the documentation for the pilot to try anything
else.

Also interesting to see is the amount of times the pilots bring the nose up,
only for MCAS to kick in and force the nose back down. 26 times.

All data from this Seattle Times article, which was written before the second
crash occurred: [1] [https://www.seattletimes.com/business/boeing-
aerospace/black...](https://www.seattletimes.com/business/boeing-
aerospace/black-box-data-reveals-lion-air-pilots-struggle-against-
boeings-737-max-flight-control-system/)

~~~
zubspace
There's one thing I don't understand while looking at the flight recorder
data:

After flaps are retracted for the final time, the altitude seems to stabilize.
So why the sudden drop before the crash? Why couldn't the pilots just keep on
flying on the same level?

There must be a sudden behavioural change of the plane or the pilots right
before it went down, but I never got it explained to me clearly why...

Second question: why did they retract the flaps? Wouldn't the wings generate
more lift with flaps extended?

~~~
tomglynch
IIRC, the pilot increased thrust to increase airspeed which made it harder to
pull back on the yoke to fight against MCAS. I will need to check references
again but I just got into bed.

Edit: here we go: Pilots have demonstrated in simulator that the trim wheels
cannot be moved in severe mis-trim conditions combined with a high
airspeed.[92][93] As the pilots on Flight 302 pulled on the yoke to raise the
nose, the aerodynamic forces on the tail’s elevator would create an opposing
force on the stabilizer trim jackscrew that would prevent the pilots from
moving the trim wheel by hand.[86][91][94]

The resolution for this jammed trim issue is not part of Boeing's current 737
manual according to The Air Current.[90] The Seattle Times reports pilots on
the 737-200 were trained for this failure, but latter models got so reliable,
this procedure was no longer necessary.[91][90]

Just stolen from Wikipedia before I sleep:
[https://en.m.wikipedia.org/wiki/Ethiopian_Airlines_Flight_30...](https://en.m.wikipedia.org/wiki/Ethiopian_Airlines_Flight_302#Expert_analysis)

~~~
dredmorbius
"Unable to trim":
[https://youtube.com/watch?v=aoNOVlxJmow](https://youtube.com/watch?v=aoNOVlxJmow)

------
dahart
> Von Hoesslin, who identified himself in the documents as a certified 737
> instructor, submitted his resignation to Ethiopian Airlines in April.

Not seeing much discussion of the guy who called it right and is losing his
job because of it. I'm not sure if there's a way to know if he's being forced
out or choosing to avoid some backlash, but it seems sad that the one person
in the story who made the right call pays a hefty price, as opposed to being
kept, protected, and/or promoted. Same thing has happened to many people
trying to do the right thing, Roger Boisjoly would be a super famous example,
one of the engineers who predicted the Challenger disaster.

Are there examples of people being rewarded for their efforts after a large
scale accident, rather than punished?

~~~
nexuist
I think this might be a case of selective bias, as people who are rewarded for
their efforts would likely prevent large scale accidents in the first place if
their management listened enough to promote them.

You likely don't hear about this, because for these cases the oversight works
and it's just people doing their jobs.

~~~
dahart
Oh, almost certainly! Failing to listen to warnings beforehand, and then after
an incident wanting to suppress the knowledge that there were warnings, are
very likely to be correlated. Not only that, there's usually a lot of money
involved, and admitting company fault could be legal liability, or I would
assume that's the fear anyway.

I'm just curious if there are any well-known cases of companies doing right by
the people who tried to avert the accident, of companies admitting it was a
management mistake as opposed to letting their fears / liability concerns /
embarrassment steamroll the only people who did the right thing.

------
salawat
>However, that report shows the pilots left the thrust too high and turned the
motor driving MCAS back on after initially switching it off.

I really wish the media wouldn't leave out important context when making
statements like this.

If you aren't a pilot or an aviation enthusiast, you'd think leaving the
thrust high was a mistake, but an on the fritz AoA sensor means you're in an
airspeed unreliable condition, which calls for maintaining appropriate power
for the desired flight regime, which in this case was TO/ascent, a regime
generally flown at higher power.

[https://www.skybrary.aero/index.php/Unreliable_Airspeed_Indi...](https://www.skybrary.aero/index.php/Unreliable_Airspeed_Indications)

Or, how leaving the airspeed issue unresolved until the more pressing issue,
the plane being continually put out of trim, is a triage call akin to what a
medical professional would be expected to make in a condition where there were
more problems to solve than hands or brains to resolve them.

Or how Boeing intentionally changed the functionality of the console
stabilizer trim cutout switches in such a way as to prevent pilots from being
able to shut out the flight computer's capability to command trim adjustments
with the trim motor, but maintaining the pilots' ability to leverage the trim
motor to neutralize trim against aerodynamic load through their trim switches
on the yoke.

[https://www.seattletimes.com/business/boeing-
aerospace/boein...](https://www.seattletimes.com/business/boeing-
aerospace/boeing-altered-key-switches-in-737-max-cockpit-limiting-ability-to-
shut-off-mcas/)

This is one of those cases where we _need_ the layman to be accurately
informed at all costs. There is no room for weasel legal maneuvering that we
as a society can afford when this comes to trial. The courts have no authority
over physics.

~~~
yread
> maintaining appropriate power for the desired flight regime, which in this
> case was TO/ascent, a regime generally flown at higher power.

But the memory item calls for 75% N1 and 4deg pitch up. Not leaving it at 94%
N1

~~~
FabHK
Is the 75% and 4deg pitch for cruise, or for initial climb out from a high
altitude airport in mountainous terrain?

------
Kye
This sure does contrast with all the early talking down about pilots in the
developing world. People were so quick to blame them instead of looking to the
people responsible for selling the planes.

------
linuxftw
DOJ needs to subpoena Boeing's internal communications for all things MCAS
during and after it's development, and everything up to date.

We don't know if MCAS is the only thing keeping the planes in the air, and if
it is easily disabled by faulty sensors in their new software update, we don't
know how unsafe those planes are.

------
WalterBright
In the flight just before the Lion Air crash, with the same airplane, the MCAS
activated wrongly, and the pilots shut off the stab trim and landed safely.

The MCAS system was known about after the Lion Air crash, and it baffles me
why pilots wouldn't have known about successful corrective action taken on the
previous flight. After all, I read about this in the newspaper. It wasn't a
secret.

It's hard to tell from the newspaper accounts, which often leave off crucial
details, but it seems the electric trim switches (on the control column)
override the MCAS commands. So the way to recover is to set the electric trim
switches to nose up, turn the trim system on at the cutoff switches, wait
until it's trimmed out properly, then turn it off via the cutoff switches and
let go of the electric trim switches.

~~~
mannykannot
>It seems the electric trim switches (on the control column) override the MCAS
commands.

...but not if you follow the procedure set out by Boeing and reiterated in an
FAR published after the Lion Air crash. The ET302 pilots recognized that they
were dealing with MCAS failure, and followed the procedure, including toggling
the trim cutout switches. On 737 NGs, one could turn off trim automation while
allowing electrical control from the yoke, but on the Max, the latter was also
disabled when these switches were toggled [1]. I don't think this way in which
the Max differs from the NG came out until later.

This created a second problem - the trim wheels are very hard to turn manually
under the load created by using the elevator to counteract the mis-trim. The
procedure in this case is to unload the stabilizer jack-screw by pitching
down, but the airplane was not high enough for that.

This might have been apparent if pilots had trained for an MCAS failure, which
brings us to a question I had in another thread: Were there any simulators
that realistically simulated MCAS failure, or were the simulator manufacturers
and operators as much in the dark about MCAS as were pilots and airlines?

[1] [https://www.seattletimes.com/business/boeing-
aerospace/boein...](https://www.seattletimes.com/business/boeing-
aerospace/boeing-altered-key-switches-in-737-max-cockpit-limiting-ability-to-
shut-off-mcas/)

~~~
WalterBright
What you're saying does not contradict that the trim switches override the
MCAS. Hence, trim could be restored by using the trim switches and throwing
the cutouts when not using the trim switches.

I read about this in the newspaper, it wasn't a secret. I do not have inside
information.

Again, if I was an MCAS pilot I'd be very interested in following what
happened with the Lion Air crash, to ensure it wouldn't happen to me. I'd
still follow the procedures set out by Boeing - but when they didn't work I'd
do what did work.

It's a little hard to discern from the erratic newspaper reports, but during
the time the pilots were fighting the MCAS they were using the trim switches
and surely would have noticed that those switches overrode the MCAS.

The reason we have pilots, and not a fully automated airplane, is we need them
to think outside of the procedures when the procedures aren't working. This is
not impossible as the pilots in the flight prior to the LA crash did have MCAS
runaway and did successfully deal with it.

~~~
salawat
It can be overridden, yes, but releasing the switch also resets the MCAS
activation timer, resulting in an activation 5 seconds after the switch is
released.

You would have to pulse the switch in sub-5 second increments depending on the
way the switch works.

If it's a direct switch, I.e. switch held down->motor moves, then they'd have
to hold it down until trim was neutralized, then cut it out.

If it's a discrete toggle, I.e. each toggle increments/decrements a set point
the motor then follows; a pilot would have to be very conscious of their
timing on the switches, and how much the stabilizer had actually managed to
travel.

Both of these would constitute new, MAX specific skills, that Boeing cannot
show any acknowledgement or foreknowledge of without opening a massive can of
worms.

~~~
WalterBright
> It can be overridden, yes, but releasing the switch also resets the MCAS
> activation timer, resulting in an activation 5 seconds after the switch is
> released.

That's why I suggested in this thread to activate the cutoff switches when the
trim is in the correct position.

The electric trim switches are a hold down => motor moves. It's not a MAX
specific skill. Neither are the cutoff switches.

~~~
salawat
>The electric trim switches are a hold down => motor moves. It's not a MAX
specific skill. Neither are the cutoff switches.

Neat!

>It's not a MAX specific skill. Neither are the cutoff switches.

Well, the cutoff switches functionality was changed according to the Seattle
Times, so while the procedure may be shared, the semantic significance of the
switches did, in fact, change for MAX.

[https://www.seattletimes.com/business/boeing-
aerospace/boein...](https://www.seattletimes.com/business/boeing-
aerospace/boeing-altered-key-switches-in-737-max-cockpit-limiting-ability-to-
shut-off-mcas/)

------
tomglynch
This type of information is very convenient for Boeing...

Edit: It's likely true, but surely nearly every airline had a pilot 'warn of
dangers'. But why is this a news story being promoted?

~~~
jamisteven
Why is it convenient for Boeing?

~~~
tomglynch
Boeing is trying to claim inadequate training (by the airlines) is the
problem, not the fact the MCAS software bandaid had serious design flaws yet
Boeing pushed for it in order to compete with Airbus.

~~~
bkor
If poor training was the cause the plane shouldn't have received the same type
number. So this is all still on Boeing. Boeing also specifically told these
planes with the benefit that only a few hours of training would be enough.

I'm not seeing how this is beneficial for Boeing.

~~~
sambull
I'm starting to think a plane that can't glide during a emergency because they
decided to deny physics is just not a good design.

~~~
_ph_
The 737 can glide as fine as a plane of that size can. The MAX didn't change
anything at that and no one was denying physics. The problem was the MCAS,
which as a result of a single sensor malfunction would aggressively point the
nose down via the stabilizer trim.

~~~
tomglynch
Yep, the reason they implemented MCAS was because they popped on some larger
engines, which were too close to the ground, so they moved them up and forward
on the wing a bit. This gave the plane a tendency to tilt up which could cause
a stall, so Boeing added some software to bring the nose down.

In both crashes, one of the two Angle of Attack sensors was incorrect. Boeing
only use one AoA sensor per flight (alternating for some bewildering reason),
and in this particular flight it was constantly incorrectly stating the plane
was nearing a stall. So MCAS would continually kick in until the Pilot could
no longer keep the plane in the air.

~~~
scifi6546
Couldn't Boeing just put in a bunch of gyroscopes into the chassis and use
that as a backup AoA sensor? (I am not a pilot so I have no clue if that is
reasonable)

~~~
ddalex
The plane attitude (what you can sense with gyros) and angle of attack are
very different things. They only coincide in level flight with no wind (the
attitude is measured to the earth frame of reference (transposed by gyros) and
the AoA is measured with reference to the local wind stream)

~~~
glenneroo
OK then why not put a couple extra AoA sensors in? I thought everything
critical on airliners was supposedly redundant?

~~~
vilhelm_s
Indeed, part of this story is that the MCAS system was not classified as
"critial" (i.e., a system which can cause a crash if it fails). If it had
been, then it would have faced additional scrutiny and they'd probably needed
three AoA sensors and majority voting. Apparently the authority of the MCAS
system was increased during development, with the criticality judgement based
on the old smaller value.

[https://www.wsj.com/articles/faa-saw-737-max-flight-
control-...](https://www.wsj.com/articles/faa-saw-737-max-flight-control-
system-as-non-critical-safety-risk-11557831723)

------
ptah
so is boeing being held liable for the deaths? corporations are people right?
a human person would probably go to jail if they did the same

~~~
erikpukinskis
Seems like a clear case of negligence, so yes, they will pay for the deaths. A
high level program manager may go to jail if there is a paper trail, but we
don’t jail people at the CEO level in the U.S. for negligence or fraud
usually.

There’s a separate system of punishment for them involving their children
hating them and acquired learning disabilities from cognitive dissonance. (Not
a joke these are actually the primary mechanism by which America holds that
class in check).

~~~
village-idiot
Can you provide more on the last paragraph? That sounds fascinating.

~~~
erikpukinskis
You can allow yourself to become corrupt in order to succeed financially, and
try to hide that corruption from your family... but A) children, with a decade
to study you, are lie detection beasts and they will see your true self, and
B) the cognitive dissonance you need to frame your abusive behavior as “normal
business” will interfere with your ability to learn new things that conflict
with your internal narrative. Those blind spots make adjacent things harder to
learn, leading to spreading blind spots, which eventually become a generalized
learning disability.

See for example the Theranos board. Living as a CEO/power broker type can lead
to debilitating dementia in middle age.

This is one of the reasons we so rarely see middle managers drop back down
into individual contributor roles. Early dementia literally inhibits the clear
thinking required for production work. In a leadership role they can rely on
the management hierarchy for executive function, but lose the ability to do it
alone.

~~~
dsfyu404ed
Those are some pretty bold claims. Care to cite your sources?

~~~
erikpukinskis
No sources, observation from life.

------
lawlessone
" The Chicago-based planemaker, while careful not to be seen blaming a
customer, has noted the role pilot actions also played in the Ethiopian and
Lion Air disasters."

"What were they doing flying our planes if they didn't want to crash?"

~~~
tomglynch
This is a lie to save face. Boeing literally decided against telling the
pilots about MCAS [1] [2].

[1] [https://www.seattletimes.com/business/boeing-
aerospace/u-s-p...](https://www.seattletimes.com/business/boeing-
aerospace/u-s-pilots-flying-737-max-werent-told-about-new-automatic-systems-
change-linked-to-lion-air-crash/)

> Jon Weaks, president of the Southwest Airlines Pilots Association, said
> Monday the airline and the pilots “were kept in the dark.”

“We do not like the fact that a new system was put on the aircraft and wasn’t
disclosed to anyone or put in the manuals,” he said in an interview. What’s
more, he noted, Boeing and the Federal Aviation Administration have now warned
“that the system may not be performing as it should.”

[2] [https://theaircurrent.com/aviation-safety/what-is-the-
boeing...](https://theaircurrent.com/aviation-safety/what-is-the-
boeing-737-max-maneuvering-characteristics-augmentation-system-mcas-jt610/)

> "Since it operates in situations where the aircraft is under relatively high
> g load and near stall, a pilot should never see the operation of MCAS. As
> such, Boeing did not include an MCAS description in its FCOM. The explainer
> continues: "In this case, MCAS will trim nose as designed to assist the
> pilot during recover, likely going unnoticed by the pilot."

There is another explanation, according to a Tuesday report in The Wall Street
Journal: "One high-ranking Boeing official said the company had decided
against disclosing more details to cockpit crews due to concerns about
inundating average pilots with too much information - and significantly more
technical data - than they needed or could digest."

~~~
mannykannot
That last statement is extremely patronizing towards airline pilots, and also
self-defeating: the more Boeing says telling pilots would have added
"significantly more technical data", the less defensible is its position that
no additional training was needed. The alternative to telling pilots in
advance was to blindside them with unexpected and inexplicable aircraft
behavior when the system failed.

~~~
FabHK
Boeing’s position was: if there is uncommanded Stab trim movement, use the
stab trim runaway checklist, just as before. No need to know why the issue
occurred in the first place.

Now, clearly that didn’t work very well, and there are many other problems,
but I wouldn’t call Boeing’s initial attitude there “lies” or “extremely
patronising”.

~~~
mannykannot
My "extremely patronising" comment was explicitly in response to one specific
statement from Boeing. Personally, I would not call Boeing's response "lies";
rather, it seems to me, it is probably being careful to not make any
objectively false statements that could come back at them in an inquiry or
court of law, while also attempting to imply that its actions always put
safety first, and that training cost avoidance was never an overriding
concern. My main point here is that, in doing so, Boeing appears to contradict
itself in a way that weakens their position on the latter issue.

