Originally Posted by
Roger_Murdock
Originally Posted by
bauble
Does anyone have any information on instances of irregular MCAS activation that have been successfully handled?
We only have two confirmed instances of MCAS activation ever. JT 610 (not handled) and the flight immediately preceding it (handled).
MCAS is only supposed to operate well outside the normal flight envelope.
I think there was potentially another instance. Perhaps, this one is also related to one [maybe both??] of the two instances where "extreme trimming" while AP engaged being reported at Aviation Safety Reporting System.
However, at the time, Southwest was concerned about the source of the automatic throttle problem during autopilot that their pilots had reported. During two separate diagnostics, they decided to replace the AOA vanes even though neither seemed to have contributed to the problem. In other word, that automatic throttle problem experienced by Southwest is still unsolved even now. Those infamous vanes escaped unscathed after a close scrutiny.
I wonder if the left AOA vane removed from Lion Air's PK-LQP in DPS, two flights prior to the fateful one, which was thought to be the source of erroneous indications would come clean as well. That will be interesting because the problem would then be in a much deeper area in the flight control sytem.
Here's the little summary of that news...
Southwest Replaced Flight-Control Sensors of the Kind Implicated in Lion Air Crash
...The accidents in the South-West caused no emergencies and no one was hurt. They pushed what appear to be routine reports from mechanics who experience sensor problems. One was written on October 9 in Baltimore and the other on October 21 in Houston, the documents show, and indicate that both sensors have been repaired...Boeing and FAA did not have immediate comments on the Southwest maintenance records. The Southwest spokeswoman said the carrier replaced the two sensors in October on the same aircraft and determined that they were not the source of the automatic throttle problem. Two other Southwest 737 MAX 8s have replaced an attack angle sensor as part of routine maintenance due to external damage, such as a bird's shot in flight...