The cosmic ray bit-flip of the 5 independent critical bits is very unlikely. We are being told right here on HN and in the news that this means the plane can't fly.
In the US there were close calls, but fewer. If you beleive in the chain of safety better maintenance and pilot response may have saved the day a few times when faced with the MCAS problems. The safety reports from US pilots certainly sound scary (nose down on takeoff GPWS alerts etc).
I brought up maintenance as a contributing cause in the 737MAX crashes. I didn't realize I had been challenged on this. I would really encourage you to read some of the source reporting.
The FAA had a safety notice on this precise topic
"FAA has determined it is necessary to advise operators of the importance of performing proper operations and maintenance on AOA sensors”
This is the detail on the previous lionair flight before the crash flight - from wikipedia to save time:
"it had problems maintaining a constant altitude, with passengers stating that it was like "a roller-coaster ride".[109] The chief executive officer of Lion Air, Edward Sirait, said the aircraft had a "technical issue" on Sunday night, but this had been addressed in accordance with maintenance manuals issued by the manufacturer. Engineers had declared that the aircraft was ready for takeoff on the morning of the accident.[110][111] A later report claimed that a third pilot was on the flight to Jakarta and told the crew to cut power to the stabilizer trim motors which fixed the problem. This method is a standard memory item in the 737 checklist.[112] Subsequently, the National Transportation Safety Committee confirmed the presence of an off-duty Boeing 737 MAX 8 qualified pilot in the cockpit but did not confirm the role of the pilot in fixing the problem.[113]
Even worse is the history before that flight - REPEATED problems with the senor.
We are also now hearing that evidence submitted by lion air supposedly showing the proper fix for the sensor may have been faked.
In terms of faulty replacement parts - my point was issues occur overseas that do not seem to happen within the US MROs. I'll do a quick recent example:
This follows the ex-president of south africa appointing a school teacher to head SAA (who also ran his private foundation and rumors around their relationship existed).
I'm not sure why you claim AoA is unimportant. In the chain of safety you want every advantage you can get, the more accurate data the better. So you want the AoA working. This reduces risks from MCAS. You are correct - AoA is not a single point of failure system (system is not working / plane falls from sky). There was a poster here claiming that it was.
I've got your point, and I think that knowing what we know now perhaps the planes could have been saved. I'm still not for blaming the pilots though: Would you have wanted to be the captain of a max while MCAS operated against a faulty AoA without having any way of knowing that MCAS existed or of the handling/stall risk that led to its creation?
Obviously not. There is a difference between blaming the pilots - I am not, and saying the plane was "unrecoverable" the system was "unstoppable".
Luckily if flying in the US the chance of the AoA being faulty in the first place would be a less I would argue than flying for lionair. My co-pilot might be quick to help. I might be quicker to get off automation and manually fly / trim.
Some of the self reports from the US specifically credit co-pilot assistance in averting a problem. See this one during takeoff - worst time to be heading towards ground at 1,500 FPM!
Within two to three seconds the aircraft pitched nose down bringing the VSI to approximately 1,200 to 1,500 FPM. I called "descending" just prior to the GPWS sounding "don't sink, don't sink."
Other side:
"PM's (co-pilot) callout on "descending" was particularly quick and welcome as I was just coming back to my display after looking away. System and procedures coupled with CRM (Resource Management) trapped and mitigated issue.
Synopsis
B737MAX Captain reported an autopilot anomaly in which led to an undesired brief nose down situation."
This was a full GPWS don't sink alert situation - very cleanly handled - the co-pilot BEAT the automated alert, the recovery was good. Should pilots have to deal with this? No. Did chain of safety work here? Yes - though closer to edge than one would like.
My own impression - US pilots much quicker to get off the automation / don't trust it as much / have more comfort or experience hand flying statistically maybe.
In the US there were close calls, but fewer. If you beleive in the chain of safety better maintenance and pilot response may have saved the day a few times when faced with the MCAS problems. The safety reports from US pilots certainly sound scary (nose down on takeoff GPWS alerts etc).
I brought up maintenance as a contributing cause in the 737MAX crashes. I didn't realize I had been challenged on this. I would really encourage you to read some of the source reporting.
The FAA had a safety notice on this precise topic
"FAA has determined it is necessary to advise operators of the importance of performing proper operations and maintenance on AOA sensors”
This is the detail on the previous lionair flight before the crash flight - from wikipedia to save time:
"it had problems maintaining a constant altitude, with passengers stating that it was like "a roller-coaster ride".[109] The chief executive officer of Lion Air, Edward Sirait, said the aircraft had a "technical issue" on Sunday night, but this had been addressed in accordance with maintenance manuals issued by the manufacturer. Engineers had declared that the aircraft was ready for takeoff on the morning of the accident.[110][111] A later report claimed that a third pilot was on the flight to Jakarta and told the crew to cut power to the stabilizer trim motors which fixed the problem. This method is a standard memory item in the 737 checklist.[112] Subsequently, the National Transportation Safety Committee confirmed the presence of an off-duty Boeing 737 MAX 8 qualified pilot in the cockpit but did not confirm the role of the pilot in fixing the problem.[113]
Even worse is the history before that flight - REPEATED problems with the senor.
We are also now hearing that evidence submitted by lion air supposedly showing the proper fix for the sensor may have been faked.
https://www.seattletimes.com/business/questions-raised-about...
In terms of faulty replacement parts - my point was issues occur overseas that do not seem to happen within the US MROs. I'll do a quick recent example:
https://www.pressreader.com/south-africa/sunday-times-1107/2...
This follows the ex-president of south africa appointing a school teacher to head SAA (who also ran his private foundation and rumors around their relationship existed).
I'm not sure why you claim AoA is unimportant. In the chain of safety you want every advantage you can get, the more accurate data the better. So you want the AoA working. This reduces risks from MCAS. You are correct - AoA is not a single point of failure system (system is not working / plane falls from sky). There was a poster here claiming that it was.