Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS
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Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS
#2So they removed a useful, granular functionality (switching off autopilot trim input while retaining electric-assisted manual trim) and made one switch simply a redundant backup, merging the previously separated functions without clear explanation.
A cynical man could be inclined to think that with this change, they casually removed a possibility of pilots/airlines realizing the existence of MCAS: "we have thrown off the right switch to unlink the autopilot from the trim motor and there is still something making automated stabilizer inputs, what could it be?"
Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS
#3It has been fascinating to watch layer after layer peel back around all of this.
Bad design decisions forced from chasing the bottom dollar, optional, critical safety features with the warning indicator and now these switches.
> Boeing declined to detail the specific functionality of the two switches
That's also interesting- I assume they are in CYA mode and wouldn't discuss anything that could be sensitive to the current investigations in any point. I wonder how hard the Seattle Times had to work to get manuals for the MAX.
I hope the loss of life is vindicated in the end.
I hope there are lessons learned from this but I fear our culture of quarterly profits and lack of real punishment for companies and their directors will result in nothing drastic happening.
Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS
#4It has been fascinating to watch layer after layer peel back around all of this. Bad design decisions forced from chasing the bottom dollar, optional, critical safety features with the warning indicator and now these switches. > Boeing declined to detail the specific functionality of the two switches That's also interesting- I assume they are in CYA mode and wouldn't discuss anything that could be sensitive to the cu…
One of the lessons learned is that the FAA is no longer a credible institution.
Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS
#5>A cynical man could be inclined to think that with this change, they casually removed a possibility of pilots/airlines realizing the existence of MCAS: "we have thrown off the right switch to unlink the autopilot from the trim motor and there is still something making automated stabilizer inputs, what could it be?"
It's worse actually. They've taken a procedure, and are raising it on a pedestal as if to say "See, this is how a 737 flies! It's all right there! You can stop looking now!"
It's as if they don't want anyone to realize that this plane simply does not fly like a 737. Which is what has been getting shouted from the rooftops since the first disaster.
What I find wickedly ironic was it was exactly Boeing's insistence to "not inundate" flight pilot's with technical information, and give an accurate accounting of the vast differences in the minute details of the aircraft that created the problem.
Someone looked at the checklist item of "both stab trim switches to cutout", didn't look into what that actually meant, and changed the plane to fit the procedure. This change cost extra effort. Instead of using the same switches and wiring they were using before, they actually degraded the granularity of control of the plane to hide the differences.
I can't imagine the thought process at the time. Be nice to see what the documentation turns up.
Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS
#6It has been fascinating to watch layer after layer peel back around all of this. Bad design decisions forced from chasing the bottom dollar, optional, critical safety features with the warning indicator and now these switches. > Boeing declined to detail the specific functionality of the two switches That's also interesting- I assume they are in CYA mode and wouldn't discuss anything that could be sensitive to the cu…
One of the lessons learned is that the FAA is no longer a credible institution.
Gotta love deregulation. How many institutions are left? Any? CFPB, EPA, HUD, Interior are all run by people that don’t believe in their missions. It’s all about undermining from inside. Who protects the public when private rights of collective action are forbidden by arbitration agreements and the government has been captured by private interests?
Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS
#7> As various warnings went off in the cockpit, they never reached the conclusion to use the runaway stabilizer procedure.
We continue to put the microscope on Boeing but this is why there is a person in the cockpit: to oversee the planes automated systems. There were multiple failures, and while we pick apart Boeing, we have not done the same to the pilots.
Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS
#8One thing that appears concerning in the series of articles being written about the 737 Max incidents is that they suggest a culture at Boeing of speed/cost over safety.
Now we can assume that the Max won't re-enter service until this issue is completely solved (I'm sure regulators will be extra-scrupulous here and customers will want cast iron re-assurance).
However, is anyone going over all the other safety decisions and changes made to other Boeing models over the period of the Max development?
It seems unlikely that this was an isolated incident of rushing things for commercial benefit...
Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS
#9> As various warnings went off in the cockpit, they never reached the conclusion to use the runaway stabilizer procedure. We continue to put the microscope on Boeing but this is why there is a person in the cockpit: to oversee the planes automated systems. There were multiple failures, and while we pick apart Boeing, we have not done the same to the pilots.
If a hazard or potential failure mode can be eliminated in the design of a system, it's better to do that than to rely on every single operator to mitigate it individually.
Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS
#10> As various warnings went off in the cockpit, they never reached the conclusion to use the runaway stabilizer procedure. We continue to put the microscope on Boeing but this is why there is a person in the cockpit: to oversee the planes automated systems. There were multiple failures, and while we pick apart Boeing, we have not done the same to the pilots.
The core of the discussion precisely revolves around Boeing wilfully making it more difficult for the person in the cockpit to oversee the planes' automated systems.