This report contains an
analysis about the consequent crashes of Boeing 737 Max that took away the lives
of 387 people. We all agree that business is made to make money but that should
not be done by the neglecting the risk factors of human lives. Boeing has well certified
and customer satisfied 737 model which they had upgraded by doing some changes in
aerodynamic structures and proposing new software and named it Boeing 737 max.
Design of Boeing 737
max
In continuation of
aforementioned model upgradation, they brought this model with more fuel efficiency
for that they had made some upgradation in the structure as following-
Aerodynamic change:
The split tip wingtip device is designed to reduce vortex drag, improving fuel efficiency and maximizing lift. A MAX 8 with 162 passengers on a 3,000 nautical miles (5,600 km) flight is projected to have a 1.8% better fuel burn than a blended-winglet-equipped aircraft and 1% over 500 Nmi (930 km) at Mach 0.79. The new winglet has a total height of 9 feet 6 inches (2.90 m).
Other improvements include a re-contoured tail
cone, revised auxiliary power unit inlet and exhaust,
aft-body vortex generators removal, and other small
aerodynamic improvements.
The engines on the 737 MAX were also repositioned,
resulting in a change to the aerodynamic characteristics of the aircraft. Due
to the aircraft's engine’s close proximity to the ground, the larger and more
fuel-efficient engines did not have enough clearance. As a result, the engines
were shifted higher and further forward on the wings, changing the aerodynamic
characteristics. The MCAS software was introduced to control flight for
the undesirable aerodynamic changes.
Effect of aerodynamic changes:
Earlier I talked about the
repositioning of the engines. As a consequent effect of this, the aerodynamic characteristic
got changed. Also, the thrust line of the wings got changed and this benefits
the aircraft to get extra lift which is beneficiary at the time of take-off. Besides
this advantage there arose a problem of angle of attack. The angle of attack of
the aircraft got risen up, to solve this issue company introduced an automatic
software called MCAS which was functioning to mitigate this issue.
MCAS (Manoeuvring Characteristics Augmentation System) software:
It enters into the picture as
soon as the flaps retracted.
Reason behind crashing:
·
There are two Boeing
aircraft which crashed consequently, one is Lion airflight 610 and other one is
Ethiopian airlines flight 302. In both the cases, it was reported that one of the
sensors (left) which measure the angle of attack got faulty and showing the erroneous
data.
·
The plane’s left
sensor, the one that apparently controlled the MCAS system, recorded an angle
of attack at 74.5 degrees — far higher than would be conceivable. A stall would
typically be a risk before 20 degrees. The sensor’s value remained stuck. But even though the sensor was no longer showing even slight
fluctuations and was stuck at an inconceivable value, MCAS continued
considering it valid data.
·
At this point pilots were trying to took over the control from
the MCAS software algorithm by all possible way such as electric power off, accessible
by thumb switches on the yoke, and by pulling back on the control column, the
pilots were able to move the nose back up. Along with this they were on the
contact of ATCs. But in spite of this efforts the MCAS software algorithm engaged
with the control repeatedly and pilots were unable to stop it. Also, the Ethiopian
airline pilots did the software switch off and tried to control the jet manually
by rotating the wheel of Horizontal stabilizer but it seems like impossible to control
the jet as that high speed.
·
The above points also indicate the pilots were no trained about
the new software and they didn’t know how to manage the emergency situation.
·
Finally, nearly 5 to 7 min of this subsequent problems, the jet
got out of control of the pilots and crashed.
·
This accident rise question about the development and algorithm
of the MCAS software.
·
Another concern of this accident is that the management of the
Boeing and FAA certification of flight.
Solution:
·
MCAS should
update and make the system rely on two AOA (angle of attack) sensors, and the
computer monitors the sensor variation and disables it if the sensors differ by
more than 5.5 °.
·
The changes
prevent the MCAS from being activated repeatedly and ensure that pilots can
always override the MCAS stabilizer.
·
Boeing should
also develop new training to help pilots better understand MCAS.
·
Boeing could analyse
the possibility of adapting the structure of the 737' to advanced technologies,
producing a new model that efficiently manages the hardware and architecture
changes of the aircraft.
END
