boing 737max scandal, starting with the end result and going back to which flaws in the process allowed it to happen. I presented it internally, emphasis the importance of system tests and E2E tests.

1. Boeing 737 max

2. Chapter one
THE END

3. Flight 610, flying from from Jakarta’s
International Airport on October 29, 2018
On board are 189 people: 181 passengers, 2
pilots, and 6 flight attendants.

4. 🕥 6:20 16 sec
Flight 610 was given clearance.
Unusual readings were recorded while still on the
ground
- Two displays in the cockpit recorded different
wind speeds
- 2 sensors that measure its orientation in the air,
disagreed by a substantial 21 degrees

5. 🕥 6:20 32 sec
“control column stick shaker”
“takeoff configuration warning”

6. 🕥 6:20 40 sec
takeoff

7. 🕥 6:21 12 sec
The first officer told the captain that on-board
sensors were giving two different altitude
readings, more than 200ft apart.
The captain spoke with an air traffic controller
in the terminal, who said to climb higher.

8. 🕥 6:21 28 sec
The first officer asked the controller to confirm
the altitude of the plane. The controller said it
was 900ft. On the plane, one display said 790ft,
the other said 1,040ft

9. 🕥 6:21 37 sec
The captain asked the first officer to run
through a memorized checklist for what to do
when the plane is giving unreliable airspeed
readings.

10. 🕥 6:22 24 sec
The captain and controller agreed that the plane
should climb to 5,000 feet.
The plane still showed two different speeds.

11. 🕥 6:22 48 sec
Sensors on the plane radically disagree
about its angle of attack.
One says the plane is flying with its nose
pointing 18 degrees up, the other says it is
flying with the nose 3 degrees down.

12. 🕥 6:23 4 sec
The control column stick shaker again warned of
a possible stall.
The plane warns of both too much speed and not
enough speed.

13. 🕥 6:23 9 sec
The captain asked the first officer for a
memorized checklist of what to do
He gets no reply.

14. 🕥 6:23 15 sec
MCAS -An automatic system on board the
plane begins to force its nose down,
activating for 11 of the next 17 seconds.

15. 🕥 6:23 39 sec
The cockpit voice recorder picks up a sound
of pages turning, suggesting the pilots
looked at a manual.
The captain turned the aircraft nose up.

16. 🕥 6:24 5 sec
The captain again asked for a checklist of
what to do when the plane’s airspeed
recorders can’t be relied on, but the first
officer said he could not find it.
The cockpit voice recorder again picked up
the sound of pages turning.

17. 🕥 6:25 27 sec
MCAS pushes the nose down for two
seconds.
The captain interrupted it, pushing the nose
up for six seconds.

18. 🕥 6:25 40 sec
MCAS activated six times in the next two
minutes, pushing the plane’s nose down
until the captain interrupted it.

19. 🕥 6:27 - 6:30
MCAS activated four more times in the next
minute.
The captain called for an airline engineer
who was on board to come in.
MCAS activated several times more, and the
captain said:
“Look what happened”

20. The captain told the controller that he could
not work out his altitude because the sensors
were giving so many different readings.
Seemingly flustered, he referred to the flight
as number 650 instead of 610.
🕥 6:31 8 sec

21. The captain asked the controller to clear all
planes from 3,000 feet above and below the
plane to avoid any collisions.
🕥 6:31 19 sec

22. The first officer twice told the captain that
the plane was flying downwards. The second
time, the captain said “it’s OK.”
The plane was descending relatively gently,
at around 1,920 feet per minute. MCAS
activated again.
🕥 6:33 19 sec

23. 5 seconds later, the plane warns of its rapid
descent and the approaching sea.
There is almost no time left.
🕥 6:33 51 sec

24. MCAS activated for a final time.
One second later, the flight record and
cockpit voice recorder stop working.
Air traffic control tries six times to contact
the pilots, to no response.
No survivors.
🕥 6:33 51 sec

25. Chapter two
MCAS
( Or how to DoS a 737 max )

27. MCAS would trigger in narrow circumstances.
“a nose down command to oppose the pitch up.
Command is limited to 0.6 degrees from trimmed
position.”
Will rely on 2 sensors
Initial design

28. Can the MCAS system fail ?

30. Boeing came up with a probability for MCAS
failure of about once every 223 trillion hours of
flight.
In its first year in service, The MAX fleet logged
118,000 flight hours.

31. MCAS

33. The same lack of smooth stick forces was also
occurring in certain low-speed flight
conditions.
Engineers increased the power of the system at
low speed from 0.6 degrees of stabilizer nose-
down deflection to 2.5 degrees each time it was
activated.
2.5 degrees = unlimited authority if pilots
would not intervene.
Problem

34. Boeing never flight-tested a scenario in which a
broken angle-of-attack sensor triggered MCAS
on its own

35. How to disable MCAS

36. MCAS and its failings are now well-known in
the aviation world.
But many 737 Max pilots say they had no idea
it even existed until after the crashes.
It probably took the two Lion Air pilots totally
by surprise.

37. 1. Why did boeing created a new system ?
2. How come no one knew about it ?

38. Chapter three
Chekhov's gun
( A pistol on the wall on the first act, will fire
in the last act. )

39. Boeing, founded in 1916, dominated the
passenger-jet market with its 737 midsize jet
and the 747 jumbo jet.
For decades, Airbus was barely on Boeing’s
radar.
Airbus is a consortium started in 1970 by
several European countries

40. 2008
Airbus :483 airplanes
Boeing: 375 airplanes
2010
Airbus, updating its A320 model
with a new geared turbo fan
engine. The engine would make
the plane 15% more fuel efficient
1994
John Leahy, an American who
rose through the ranks to
become the chief Airbus
salesman
1999
JetBlue decided to launch with
a fleet composed entirely of
Airbus A320s
2011
American Airlines, an
exclusive Boeing customer for
more than a decade, was ready
to place an order for hundreds
of new, fuel-efficient jets
from the Airbus.

41. At the heart of Boeing’s push was a focus on
creating a plane that was essentially the same as
earlier 737 models

42. 1. Important for getting the jet certified quickly.
2. Help limit the training that pilots would need,
cutting down costs for airlines

43. Vestibulum congue
Vestibulum congue
Vestibulum congue
Vestibulum congue
Vestibulum congue
Vestibulum congue
Few
modifications
Fuel Efficiency
Time to market

45. New and a poorly tested
system
Single point of failure
Poor training
Cutting corners on
regulation steps

46. Chapter four
Epilog

47. Oct. 29,
2018
A 737 MAX 8 operated
by Lion Air crashes
after departing
Indonesia, killing all
189 people on board
Nov 6
Boeing issues a
bulletin detailing
what pilot should do
in the event of a
sensor failure that
may cause the plane
to point its node
down.
March 10, 2019
A 737 MAX 8 operated
by Ethiopian Airlines,
killing all 157 people
on board
March 11
Boeing says it will
introduce FAA-
approved changed to
the flight control
system no later than
April
March 12
International agencies
ground the 737 MAX.
March 13
U.S authorities
ground the MAX,
saying “new
evidence” shows
similarities between
2 deadly crashes.

48. Resources
Link Description
crash timeline This timeline shows exactly what
happened on board the Lion Air Boeing
737 Max
casuality Podcast, part of the The Engineered
Network - A network of shows about
all facets of engineering
Risk management FAA Principles of System Safety