New flaw discovered on Boeing 737 Max, sources say

more at https://www.cnn.com/2019/06/26/polit...law/index.html

(CNN) — A new flaw has been discovered in the computer system for the Boeing 737
Max that could push the plane downward, according to two sources familiar with
the testing, an issue that is expected to further delay the aircraft's return to
service.

A series of simulator flights to test new software developed by Boeing revealed
the flaw, according to one of the sources.

The latest versions of Boeing's popular jet were grounded in March after two
crashes -- Lion Air flight 610 and Ethiopian Airlines flight 302 -- that killed
346 people.

While the crashes remain under investigation, preliminary reports showed that a
new stabilization system pushed both planes into steep nosedives from which the
pilots could not recover. The issue is known in aviation vernacular as runaway
stabilizer trim.

Boeing announced it could break the chain of events that led to both crashes by
developing a software fix that would limit the potency of that stabilization
system.

In simulator tests, government pilots discovered that a microprocessor failure
could push the nose of the plane toward the ground. It is not known whether the
microprocessor played a role in either crash.

When testing the potential failure of the microprocessor in the simulators, "it
was difficult for the test pilots to recover in a matter of seconds," one of the
sources said. "And if you can't recover in a matter of seconds, that's an
unreasonable risk."

Boeing engineers are now trying to address the issue, which has led to another
delay in recertifying the 737 Max.

"The safety of our airplanes is Boeing's highest priority. We are working
closely with the FAA to safely return the MAX to service," Boeing said in a
statement.

The sources say Boeing engineers are trying to determine if the microprocessor
issue can be fixed by reprogramming software or if replacing the physical
microprocessors on each 737 Max aircraft may be required.

An FAA spokesperson would not confirm the specific issue, but told CNN that "the
FAA's process is designed to discover and highlight potential risks. The FAA
recently found a potential risk that Boeing is required to mitigate."



more at https://www.cnn.com/2019/06/26/polit...law/index.html



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