jm + mcas   2

Pilots had 40 seconds to fix error in tests of Boeing 737 Max flight
During flight simulations recreating the problems with the doomed Lion Air plane, pilots discovered that they had less than 40 seconds to override an automated system on Boeing’s new jets and avert disaster.

The pilots tested a crisis situation similar to what investigators suspect went wrong in the Lion Air crash in Indonesia last fall. In the tests, a single sensor failed, triggering software designed to help prevent a stall.
Once that happened, the pilots had just moments to disengage the system and avoid an unrecoverable nose dive of the Boeing 737 Max, according to two people involved in the testing in recent days.
boeing  737max  mcas  fail  planes  safety  disasters 
27 days ago by jm
Flawed analysis, failed oversight: How Boeing, FAA certified the suspect 737 MAX flight control system
omg this article is absolutely horrific. Boeing are in deep shit if this is borne out.
Like all 737s, the MAX actually has two of the sensors, one on each side of the fuselage near the cockpit. But the MCAS was designed to take a reading from only one of them.

Lemme said Boeing could have designed the system to compare the readings from the two vanes, which would have indicated if one of them was way off. Alternatively, the system could have been designed to check that the angle-of-attack reading was accurate while the plane was taxiing on the ground before takeoff, when the angle of attack should read zero.

“They could have designed a two-channel system. Or they could have tested the value of angle of attack on the ground,” said Lemme. “I don’t know why they didn’t.”

The black box data provided in the preliminary investigation report shows that readings from the two sensors differed by some 20 degrees not only throughout the flight but also while the airplane taxied on the ground before takeoff.
faa  aviation  boeing  737max  safety  fail  sensors  flight  crashes  mcas 
5 weeks ago by jm

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