scbriml wrote:
Boeing deliberately withheld information about MCAS from the one group that most critically needed to know about it. All in a desperate attempt to be able to claim that pilots needed no training to transition from NG to MAX (apart from a few slides on an iPad).
The implementation of MCAS was shamefully incompetent and hiding a system from the pilots that would pitch the plane down in certain circumstances, simply in order to save money was appalling.
I think his point was that MCAS training had nothing to do with the accidents, but basic airmanship skills had everything to do with them.
In the broadest possible sense, the MAX accidents occurred because the crews did something Boeing had presumed no crew would ever do: fight the stabilizer with the elevators. That's a physical impossibility because the elevators have only a fraction of the surface area of the stabilizer.
This has been known since the all-moving stabilizer was introduced in the 1960's. It's far more efficient and provides better trim control of the aircraft. But it has the drawback that a malfunction will absolutely overwhelm the control column.
For that reason, all such aircraft have a means of stabilizer disablement, and all pilots are trained to use it, rather than pushing back with the control column. This method and practice has been successful for 50 years. Until it wasn't.
In the House Transportation Committee report, there is an e-mail from a Boeing engineer, who was asked about the safety risk of multiple MCAS activations. His response was that it wouldn't be an an issue, unless the pilots tried to fight the stabilizer. The report claims this is evidence that Boeing knew MCAS contained a fatal flaw. But the true context of the response, was that everyone knows not to do that, therefore no one would.
It's notable that this was also the approach of the FAA, in requiring Boeing to address the MCAS issues. Boeing was told, you cannot within your safety analysis of automation, presume a crew action to avoid a catastrophe. Instead your analysis must presume the crew takes an action other than the correct one. And the aircraft must remain stable and controllable while they figure it out.
That was the basis of the flight control software rewrite, that went far beyond MCAS. The FAA asked Boeing to remove any similar dependence on crew actions. The aircraft has to tolerate the crew not responding, or responding incorrectly.
This is also why the debate between "blame the pilots" and "blame Boeing" is so completely and utterly pointless. The aircraft unifies the crew and the automation into a single system. Both have to perform in accordance with their design and training. And if they don't, then they have to fail gracefully together.
Boeing is guilty of making a presumption that did not provide for a graceful failure, in the event of crew error. The presumption was made for a benign version of MCAS which could apply less than 10 pounds of force to the control column, and which also had a redundant accelerometer check on the AoA vane. That system could not produce a fatal crash.
When the MCAS authority was increased, such that the applied column forces reached 35 to 40 pounds, and the accelerometer was removed, the system was no longer benign, and the presumption & safety analysis based on it, became invalid. That is totally on Boeing.
The crews were guilty of not executing their training for stabilizer malfunction, as well as committing other errors in basic airmanship. This is why the FAA required demonstration of those skills, before resuming MAX duties. That is totally on the airlines, who were guilty of not having the programs in place to assure quality airmanship.
Lastly, the FAA found in random pilot testing, that this situation was not unique to those two airlines. Crews were found to sometimes stray from their memory and QRH checklists, and in some cases, not recovering. So this is an ongoing problem and issue in the industry. The FAA and EASA both have in their charters, to work with ICAO to encourage high training standards around the world, and to improve the design and training around automation. That's being done for a reason.