RatherBeInYOW

You can keep calling MCAS a "stall prevention" system, but that doesn't make it any more true. The MAX is flyable if "control is returned to the pilots" - they just need to keep it in trim manually, and this doesn't "defeat the purpose" of anything, any more than it does any other part of the auto trim system, or the autopilot system, on any plane that relies on such things -- which is to say every modern commercial aircraft.

If you want to use pitot tubes as an example, try this: Incident: Virgin Australia A320 near Perth on Sep 12th 2015, automated flight system issue. Sure "control is returned to the pilots" but then they have to diagnose the issue correctly and still fly the plane. In this case software issues on the A320 prevented a correct diagnosis and nearly led the pilots to stall the aircraft on approach. If they had and 145 people were killed this would be more than just a footnote, it would be up there with AF447. Or how about AoA failures? Accident: Qantas A333 near Learmonth on Oct 7th 2008, sudden inflight upset injures 74 people on board ... uncommanded pitch down based on erroneous AoA, resulting from software bugs - just happened at an altitude that managed not to kill anyone. Returning control to the pilots in the event of catastrophic sensor failures doesn't result in a magically successful outcomes on any commercial aircraft - it requires correct diagnosis of the failures and requires the pilots to fly and land the aircraft in absence of automated systems that they usually rely on, and sometimes requires them to keep fighting those automated systems even when they have "control".

The problem with MCAS isn't that it exists. The problem, from what we know so far, and that has been repeatedly beaten to death is 1) it was extremely poorly designed and 2) it was not properly documented, likely to cut costs. From the preliminary reports we also don't know if it was only MCAS that contributed to the problems that lead to these two accidents, which is why the plane will likely remain grounded in the US much longer than it takes Boeing to get the FAA to approve the MCAS fixes, not to mention the promises of TC and EASA to get involved to certify the aircraft again in Canada and Europe.

Stranger

RatherBeInYOW

This is literally nonsense.

The Lev

I think you are misinterpreting the point I was making.

@fjordland was suggesting it was a problem with AC's corporate culture that they had failed to dig into the MCAS system in depth before buying the MAX. i pointed out that 79 other airlines apparnetly had done the same thing and that not a single airline had expressed safety concerns about the MAX as an explanation for ordering the competing Airbus product.

Of course since the crash both Lion Air and Garuda have already shown their hands by announcing their intent to cancel their Boeing MAX orders.

skybluesea

delete

bimmerdriver

The latest video by Juan Brown is linked below. Based on the preliminary report, he is taking the position that the pilots made two significant errors. First, they did not control the speed of the aircraft. Second, they reengaged the MCAS by closing the breakers. Both of these actions are contrary to the runaway stabilizer trim check list and the AD that was issued after the first crash.

I don't see how anyone can consider this report and not attribute at least a portion of the blame on the pilots. Personally, I don't disagree that MCAS has major deficiencies, but I believe this crash could have been prevented by the pilots. Interestingly, Juan makes the comment at around 13:25 that when a pilot takes charge of a situation, "years and years of training begin kicking in" to help resolve the situation. I guess you can't expect years and years of training to kick in when you only have 200 hours of flying time. Again, I'll side with Sullenberger who said that 200 hours of flying time is "an absurdly low amount for someone in the cockpit of a jet airliner."

Here is the video:

fin 645

Sourced from Bloomberg:
https://www.smh.com.au/business/comp...12-p51dew.html

"Boeing said in a legal document that large, upgraded 737s "cannot be used at what are referred to as 'high/hot' airports.....Boeing cited the performance of the 737 Max 8 in a case brought before the US International Trade Commission in 2017. Boeing charged that unfair competition from Bombardier - which beat out Boeing for a large order from Delta Air Lines - threatened its 737-700 and Max 7, the smallest of its upgraded single-aisle jets. By pointing out the limitations of the Max 8, the planemaker sought to preserve market share for the 700 and Max 7."

skybluesea

delete

The Lev

...and yet Boeing happily sold the aircraft to Ethiopian knowing that they would be operated from ADD. I'm sure that will look good on them when they end up in court.

Thanks for sharing the video. After watching it here are my thoughts: It is entirely possible that the actions of the pilots as described above and in the video were contributing factors that led to the crash, but we don't have enough information from the preliminary investigation to make that determination. So no I am not yet ready to "attribute a portion of the blame to the pilots" (although that may well come out in the final investigation. In particular:

• The emergency directive from Boeing tells the pilots to switch off the auto throttle. We don't know whether they did so or not. The emergency directive from Boeing does not say anything about what to do once auto throttle is disengaged - in particular there is nothing about keeping speed below a certain level to ensure that the pilots can actually manually trim. But I suppose that's only a minor detail that the pilots didn't need to know - just like MCAS.
• Pilots know that reduced speed = increased angle of descent. As such their natural instinct would be to maintain/increase speed. Again no warning from Boeing to keep speed down.
• The pilots re-engaged the stab trim. The inference is that they did this because they were inexperienced third world dudes who didn't know what they were doing. That is a possibility. Another possibility is that having followed the instructions, they were still unable to control the plane and they had determined it was going to crash. Rather than simply following the instructions to their death, they tried the only thing they could think of to regain control of stab trim. As we know that didn't work out too well for them, but I'm not willing to assume that they were happily controlling the severely out of trim aircraft and just decided to re-engage the stab trim for jollies.

In terms of "years and years" of training, the pilot had 8,000 hours of flying time. That is years and years of training/experience. Agree that his copilot at 350 hours was on the light side by North American standards but there is a far different training regime in other parts of the world so it's not quite apples to apples.

canopus27

Lev has exactly and concisely captured my opinions, too. I'm not going to rule out blaming the pilots until the final report comes out, but I can envision plenty of scenarios that would outwardly look very similar to what we know so far, and leave even Sully in a very bad place.

BTW, the FO in the incident flight may have had a small number of hours, but my reading of what he said & did is that he was right on the mark - he was the one who first called for the stab trim cut-out, I see no evidence that he did anything incorrect with his flight controls, and he advised the captain and assisted as best able. This is not at all like AF 447, where it was obvious the primary problem was sitting in the right seat.

RatherBeInYOW

Agree with everything you wrote but take a bit of exception to the above. Managing your speed is part of keeping the aircraft in the air and piloting 101; you don't need an AD from Boeing to know that you don't keep TOGA power applied in level/descending flight, run the aircraft what, 100+mph over max speed, have overspeed alarms going off, etc. Now maybe this can be explained by the sheer amount of information snd problems they were dealing with; disagreeing instruments, alarms, stick shaker, trim issues, etc. etc. But it still happened, and will still likely be a contributing factor in the final report.

yulred

InTheAirGuy

Intersting read:

yyznomad

For those who cannot see the original twitter link.

canadiancow

Or if you want a much easier reading experience: https://threadreaderapp.com/thread/1...177137152.html