Originally Posted by
OldnGrounded
We're way past the point where it's an either/or selection. The MAX is not going to fly again until a long list of people agree that MCAS has been fixed (hardware, software, whatever) and pilots have received training as agreed appropriate by the various stakeholders.
My point is that if the software/hardware has been properly fixed, repeat properly, there would be no need for special training on how to manage it if and when it goes wrong. The special training should not need to be part of the solution. If there is no longer a problem, what is it for?
If special training is really needed, there is still a problem which needs fixing. Why do commercial pilots not receive special training on what to do when an aileron falls off? Because everyone has total confidence that it won't happen, that's why. Now apply that thought to the MCAS system.
Here's Boeing;
Boeing has developed an MCAS software update to provide additional layers of protection if the AOA sensors provide erroneous data. The software was put through hundreds of hours of analysis, laboratory testing, verification in a simulator and two test flights, including an in-flight certification test with Federal Aviation Administration (FAA) representatives on board as observers.
The additional layers of protection include:
- Flight control system will now compare inputs from both AOA sensors. If the sensors disagree by 5.5 degrees or more with the flaps retracted, MCAS will not activate. An indicator on the flight deck display will alert the pilots.
- If MCAS is activated in non-normal conditions, it will only provide one input for each elevated AOA event. There are no known or envisioned failure conditions where MCAS will provide multiple inputs.
- MCAS can never command more stabilizer input than can be counteracted by the flight crew pulling back on the column. The pilots will continue to always have the ability to override MCAS and manually control the airplane.
These updates reduce the crew’s workload in non-normal flight situations and prevent erroneous data from causing MCAS activation.
''There are no known or envisioned failure conditions where MCAS will provide multiple inputs''. I refer you to Donald Rumsfeld;
But there are also unknown unknowns - the ones we don't know we don't know.
Here's a random question. If there is a sensor disagreement =>5.5 degrees MCAS will not operate. OK, but if the crew can, without MCAS, manage safely the pitch-up condition in which MCAS would operate if the AOA sensors agree, what exactly is MCAS there for?