Revelation wrote:At the risk of being bitten as I throw red meat into the lion's cage, here is how Boeing explains itself ( ref: AvWeek ):Commenting on criticism of the single-string-failure potential of the AOA input to the MCAS, a Boeing executive says the original design was based on a standard industry process of hazard classification, which defined the potential failure as one that could be mitigated “very quickly by a trained pilot using established procedures.”
“In this particular case, because we don’t know yet what the ultimate cause is, we can look at that one link in the chain and say we know ways to update the MCAS functionality to make it more robust, and that’s what we are doing,” the executive says. “While certification standards say a runaway stabilizer has a memory procedure associated with it—despite all of that, we are looking at it and saying, ‘We don’t want to intentionally provide the pilot with that scenario again.’ So in the design, we are using multiple inputs, even though in the original hazard classification, multiple inputs would not be required. We’ve seen two accidents, and we believe it’s appropriate to make that link in the chain more robust.”
While some here won't be sympathetic to this explanation, I personally think it's important we understand what the explanation is, right from a company executive.
My understanding of the context is that during this week's gathering in Seattle the media was allowed to attend and report on a question and answer session, as long as they did not report the names of the engineers and executives answering the questions, thus the reference to a "Boeing executive" as the source of the quote. This also shows that this is a very recent statement.osiris30 wrote:Or... maybe no one realized it was that bad/a big deal.. like leaded gas or paint.. or asbestos... or all the other stupid in hindsight mistakes man as made (I used three examples but there are literally ... at least millions that someone could cite)
My interpretation of the statement above is that even as of this week Boeing still feels their original design was sufficient and that if any problem with MCAS was encountered the pilots would recognize it as a runaway stabilizer problem and invoke the associated memory procedure to resolve the problem.
As I've written in another thread, the fact that they are issuing changes is a tacit admission that their MCAS design was found wanting. Above the Boeing exec is using the words "make it more robust" which is a very similar statement, but presumably out of legal necessity, admits no guilt.
Interesting - So if the plane has two sensors linked up and they both fail - it's still the planes fault if the pilot forgets the memory procedure?
Stuff fails. Pilots have to be trained to recognize issues (runaway trim) and be able to deal with it.
Boeing really screwed up on the design (as evidenced by the other changes they are making so that even if two sensors fail MCAS won't put the plane in a nose down position), however I hope that what happens as a result on these crashes is that flight training of commercial pilots is made a lot more robust.
A well trained crew should have been able to diagnose an electric trim issue and turned it off - even if they had never heard of MCAS.
For instance if it was the Speed Trim system (which I don't believe has had issues - but parts in it can fail leading to bizarre outcomes) had an issue causing the plane to do weird things and the pilots did not know how to turn off the electric trim - is that an inherent design problem or a failure in training?
Or if the Autopilot turns the plane the wrong direction 22 times (due to a part failure) and the pilots keep using it is that the planes fault or the pilot's for continuing to rely on it?