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> In effect you are stating that you understand better than the hundreds of engineers involved with this project why these design trade-offs were made. We don'

> In effect you are stating that you understand better than the hundreds of engineers involved with this project why these design trade-offs were made. We don't know that any engineers approved this design. It could have been completely compartmentalized and approved by management only. We'll never know what the engineers said until there's a complete investigation and the engineers are subpoenaed. Here's what we know so far about the 'engineers': 1) The MCAS software was outsourced. 2) MCAS as originally designed and submitted to the FAA didn't have enough authority to affect the plane in the needed amount, so Boeing increased it's authority and never told the FAA. Point to speaks to a failure in basic engineering or a deliberate deception of the FAA. A competent engineering team should have been able to calculate exactly how much effect was needed before the plane left the ground. Sounds like they were winging it on this one.

phicoh 7y ago
I think the key thing is how the MCAS added new failure modes that the pilots where not briefed about. There should be way more strict user interface requirements. Including how humans are supposed to react to failures and whether that makes sense from human psychology point of view If the MCAS had informed pilots of a potential sensor failure, then there would have been a very good chance that the pilots would have been able to land the planes safely.
- linuxftw 7y ago
  > If the MCAS had informed pilots of a potential sensor failure, then there would have been a very good chance that the pilots would have been able to land the planes safely. Perhaps on the two crashes. We don't have any data on successful landings with MCAS disabled in very adverse flying conditions. What if the plane is unsafe to fly without proper MCAS operation? There should be a test that results in a plane crash with 50% of the simulations with MCAS behaving properly (IE, extreme weather, low fuel, land or die). Now during that same simulation, disable MCAS randomly. Also, there seems to be potential for the MCAS to come in and out based on disagreement (loose sensor wiring, etc), and see what the crash rate is for intermittent MCAS failures. It's clear Boeing didn't do any of this kind of testing because they would have easily caught the failure modes that caused the plane to nose-dive into the ground. Completely predictable based on the behavior of the system.

phicoh 7y ago

I think the key thing is how the MCAS added new failure modes that the pilots where not briefed about. There should be way more strict user interface requirements. Including how humans are supposed to react to failures and whether that makes sense from human psychology point of view If the MCAS had informed pilots of a potential sensor failure, then there would have been a very good chance that the pilots would have been able to land the planes safely.

linuxftw 7y ago
> If the MCAS had informed pilots of a potential sensor failure, then there would have been a very good chance that the pilots would have been able to land the planes safely. Perhaps on the two crashes. We don't have any data on successful landings with MCAS disabled in very adverse flying conditions. What if the plane is unsafe to fly without proper MCAS operation? There should be a test that results in a plane crash with 50% of the simulations with MCAS behaving properly (IE, extreme weather, low fuel, land or die). Now during that same simulation, disable MCAS randomly. Also, there seems to be potential for the MCAS to come in and out based on disagreement (loose sensor wiring, etc), and see what the crash rate is for intermittent MCAS failures. It's clear Boeing didn't do any of this kind of testing because they would have easily caught the failure modes that caused the plane to nose-dive into the ground. Completely predictable based on the behavior of the system.