Update 7
The offset was 60 degrees between the two AOA sensors in the case of Ethiopian Air after an incident during take off? Bird strike?
Plus the following…
MTBF is 93000 hours for the AOA. However, this is a early life failure in case of Lion Air which (the bad AOA ) apparently never worked? Replacement too?
How does the input switch between pilot side and other side between flights? Physical wiring change by maintenance crew?
— Shaker Cherukuri (@ProcessISInc) April 5, 2019
How will the flight control system known faulty sensors?
With 2 sensors, if they disagree, the fix simply doesn’t activate MCAS is difference ismore than 5 degrees as per reports.
Airbus has 3 AOA sensors and they still have issues. Apparently 2 bad ones overruled the good one
— Shaker Cherukuri (@ProcessISInc) April 5, 2019
94 % trust during take off is standar but the aircraft was over max safe speed of 250 knots?
300 knots and then 500 knots eventually. Air traffic control also noticed the high speed.
Could there be other things going on that we don’t know yet?
— Shaker Cherukuri (@ProcessISInc) April 4, 2019
The erroneous AOA sensor in the case of Lion Air never worked as per Reuters Aero news. How is this possible?
how is that MCAS can switch back and forth between good and bad sensor?
The fix is to read both sensor do nothing if difference more than 5 degrees. Doesn’t fix sensor?
— Shaker Cherukuri (@ProcessISInc) April 4, 2019
Hypothesis:
The pilots had to turn on the power to the trim motors to undo the MCAS trim.
However, due to the persistent AOA sensor offset and flawed sensor selection MCAS kept overriding the pilots aggressively.
There was no time to recover either. few hundred feet altitude.
— Shaker Cherukuri (@ProcessISInc) April 4, 2019
Cutting out the power to MCAS motors did not fix the steep dive? What does that mean?
The pilots of #EthiopianAirlines turned on the motors powering the MCAS jackscrew to undo the MCAS trim. Unfortunately there wasn’t enough time And the MCAS would retrim it down aggressively due to bad AOA offset. 20 degree offset. Same as lion Air the pilots had no chance to fix
— Shaker Cherukuri (@ProcessISInc) April 3, 2019
Cutting out the power to the MCAS motors did not fix the automated trim or the steep dive?
Or did fix the automated trim but not the steep dive?
The latter probably? Just not enough time given the low altitude?
So the pilots in desperations started trying everything.
Tragic!!
— Shaker Cherukuri (@ProcessISInc) April 3, 2019
The Integration issues:
“Issues with integration when new software is loaded into the aircraft”? 🤔
But, “nothing to do with Ethiopian “
Interpretation:
1) software is the same in all aircrafts. How it is wired in could be different.
2) is it airline specific or vintage? Meaning when it was made.— Shaker Cherukuri (@ProcessISInc) April 2, 2019
Flight control systems issue: Major upgrade in the works. Plus AOA sensor input to MCAS is not the same on all aircrafts?
This is Epic systems design and implementation failure possibly?
Different AOA sensor feeding into MCAS at divergent times? How is this possible?
Pilot side vs first officer side.
Specific to airlines?
Or vintage?
Or random?
Or integration mistakes?
Is there a specification?
— Shaker Cherukuri (@ProcessISInc) April 2, 2019
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