Another Boeing 737 Max-8 crash

What part of it was wrong?

 

The part on NETFLIX?

 

Netflix documentaries can sometimes be mostly based on a true story, but they are not above taking a little artistic and/or bias license. I have not watched the 737 one, and probably won't. My life is currently filled with enough challenges that I don't need to add any additional sources of outrage.

 

I wish an expert interviewed in the movie would have pointed out that a very simple software change could have eliminated the ability of the MCAS to have that much authority (limiting the amount of trim it could apply). Failure to put that sort of software backstop came down to incomplete requirement flowdown and lack of understanding of how flight safety (authority) requirements should have been allocated and addressed.

Besides that, a system that needed appropriate redundancy because of how much trim Authority it could develop with multiple activations. Furthermore, why weren’t failure Modes tested in a lab (SIL) and fully understood. But the movie seemed to just say, bad design because profits and it’s not due to pilot training. I felt it was a bit one sided and though Boeing is culpable, the root cause hypothesis of the movie was a bit more sensationalists and clearly attempted to pull on heart strings of people.

 

I love when you mega nerds start talking.

it’s very informative and fun to learn new stuff.

 

I'll repeat my earlier statement...Boeing should have told people what it did...but the pilots should have recognized a runaway trim issue and dealt with it appropriately. Like the other flight crews that had that issue did. That's why it's nice to have experienced and trained pilots in ATP class planes. AF 447 I'm looking at you...

 

Or highly trained SWA pilots who crashed into a gas station

 

Cold.

 

It's wrong because it's less than half the story, and the people they interviewed all have an axe to grind or a potential payday of a large pending lawsuit. Boeing won't rebut it, because of their need to sell aircraft in foreign countries where pilot training and experience is sub par. And it would be a PR nightmare which is finally starting to die down.

@Monsterdood is exactly correct as to why the software was faulty. It was also a mistake on Boeing's part to make the second AOA vane an option which the foreign carriers did not purchase.

Regarding not telling the pilots about the new software- the airplane has Speed trim, Mach trim, Autopilot trim, all of which is to say the Flight Management Computer (FMC) has the power to move the trim wheel and has since 1967. If the trim runs away, you disconnect it and fly the aircraft. Same procedure we've always had.

If your car catches fire, do you care if it's the engine, the transmission, or a cigarette causing the fire? NO, you get the fuck out and grab an extinguisher. Same procedure, no matter what originated the fault.

No doubt it was a bad and confusing situation for the pilots. BUT both of those airplanes were flyable, period.

Lion Air aircraft was broken for days, they made half assed attempts to repair it (pencil whipping the logbook, mostly) never calling the Boeing Tech Rep for Indonesia. The crews continued to fly it with a major airworthiness issue. Even the Captain on the accident flight never discussed returning to the departure airport. LionAir's own report says 3 out of 10 mechanics are "trained" whatever that means.

Yes the Ethiopians did disconnect the runaway trim, after they had allowed it to trim for way too long, and after they had accelerated the airplane close to 500 knots (140 knots+ PAST the REDLINE) at low altitude. The trim wheel is manually moveable at that speed but it's damn hard. We'll never know the truth of that accident because they have never released the full data or produced any kind of report, and they never will. They won't even turn it over to Boeing?

What I did find interesting, and has a ring of truth to it, is the corporate mentality- I have seen it at airlines before, it's almost like the HQ people forget what the primary job is- (building or flying airplanes) instead of stock prices, costs, and profits. It's infected most major corporations, and I'm sure it was a factor in this happening.

The current animus surrounding Boeing is also a product of our new media culture- Airbus knew the pitot tubes were faulty and could freeze over, and were taking action to replace them, when Air France crashed. Did they ground the Airbuses or do major expose coverage? Nah, it's much more fun to demonize the big bad rich guys in the USA. Let's not forget what is the safest form of travel in the world again? YMMV of course.

 

The only thing I have to say about that is there's a video, after the airplane plows through the fence and into the gas station, there's a car sitting at the light with a couple in it. They wait about 6 seconds, then they drive the car right up to the side of the airplane, parking it against the plane. Their lawsuit was dismissed.

 

So what of the internal emails where Boeing states they will do a anything include bullying FAA to make sure they don’t have to retrain pilots.

And the fact that they chose not to inform pilots of the MCAS system which at the very least had much more aggressive control than it ever had if it existed at all before because they knew that would throw red flags at FAA. You characterize it as part of the FMC but if you went from no FMC to FMC they’d have to train so if they added MCAs or significantly changed its control strategy, it should’ve been trained on let alone mentioned which Boeing strategically decided not to

What do you think of the study that showed pilots had 10 seconds to respond or the plane became unflyable. Seems easy enough if you know it’s coming but if not, to diagnose and respond?

Boeing willingly sells their planes to all airlines so blaming them is ridiculous. Why weren’t 737s or any other plane falling out of the sky before the MAX if it was the maintenance or pilot training?

To also bash the whistleblowers is ridiculous. The fact that Boeing allowed a single point of failure for a critical system like MCAS is proof of the profit over quality that took over with the MD merger. So sick of board rooms taking Engineers and technical people out of decision making because they care about quality

I’m also almost finished with Netflix Epstein documentary. Wondering if you’d defend him after learning about him too

 

The fact that they cut the quality control people numbers down to almost none and then ignored them or worse yet stifled them when they spoke up showed me what mattered to them. $$$$

They found a ladder in the wing of one after a test flight for christs sake !

 

I can only assume that you are getting your info from the Netflix doc, because much of what you say is technically incorrect-

I tried to explain the Electric Speed Trim system so that it was understood that many things can cause the trim wheel to move- which line of software code and it's internal designation to the programmers (MCAS, Speed Trim, Mach Trim, Autopilot Trim, etc) is moot. If the trim wheel runs away, you run the Stab Trim Runaway checklist. The common misconception is that MCAS is a separate system. It's not. It's just another line of software that causes the existing system (Electric Pitch Trim) to move the trim wheel.

The 10 seconds to correct an unflyable condition is wrong. Period. I believe what is being confused is the time they expect a pilot to react to an adverse condition. The FAA Standard for Certification is 3 seconds to recognize and react. Boeing extended that to 40 seconds. The plane takes a lot longer than that to become unflyable. Probably close to a minute. For the trim wheel to be running for 10 seconds without the pilot noticing or correcting is an egregious failure on the pilot's part to act. The Lion Air Captain recognized the failure and was trimming against MCAS and keeping the airplane in trim for several minutes- what we call "flying the airplane." The First Officer couldn't find or execute the checklist which is why he gave him the controls. Then they got bogged down talking to an airbus mechanic that was riding in the back and failed to run any of the checklists that would have saved them. Point being, time wasn't a factor anyway.

Regarding foreign airlines and their accident rates, you might want to do some research on that. Lion Air wasn't allowed to fly into the US because their safety standards were so low. Third world countries crash perfectly good modern airliners several times a year. So yes, they do shoulder some of the blame.

I didn't bash the whistleblowers, I said the pilots in the documentary have other motives. I do think the corporate culture at Boeing contributed to the failure of Boeing to give MCAS the authority to move the stab multiple times, and to sell airplanes with a single AOA vane who's failure could cause MCAS to activate erroneously. So they are not perfect, I have never said they were completely innocent. What I said, and what I stand by, is that it's only half the story.

I get a little wound up about this issue, because with 6,000+ hours in 5 737 variants, I know what's real and what's BS. So I'm sorry if I come off a little arrogant. I'm not god's gift to aviation, but I have trained on these scenarios, both before and after the crashes, and I stand by my statement that those airplanes were both flyable. Not a scenario I would ever wish for, but I firmly believe US trained airline pilots would have safely landed both of those aircraft. Just my opinion, of course.

But for you to compare me giving my opinion on these accidents and defending a disgusting pedophile and rapist? With all due respect- Get Fucked.

 

Just curious, are you familiar with the YouTube channel Mentour Pilot? He's a Swedish 737 pilot based out of Spain and he makes videos explaining the systems of the 737. He has made a couple about MCAS and exactly what to do about runaway trim and how to disable the system. As a non-pilot I obviously don't know for certain that he's correct, though the explanations he gives make sense to me.

Anyway, just curious if you were familiar with him. I'll try to drop one of the videos in the YouTube thread.

Edit to add: just dropped the video in the YouTube thread.

 

Curious about your level of subject matter expertise. Are you a pilot? Aircraft engineer? Mechanic? Holiday Inn Express?

Not taking jabs. You could have designed the goddamned A350 for all I know but I'm asking because real world context and experience matters a lot. Typically much more than info gathered from a film that's produced to lead you to one specific conclusion.

 

In regards to the second crash. I understand that the MCAS system reached it's full down elevator trim and the airspeed was to great to manually dial it out.

Was the dive and the airspeed to great to not just pull up like hell out of the dive? Does the MCAS system put so much trim into the elevator that it does not have enough angle left to operate enough to pull out of that type of situation? I'm not a pilot obviously, but to me it seems as soon as you realize you've got a runaway control issue your first impulse is full manual control, airspeed and climb.

 

I think the issue is that the bigger engines on the MAX create a nose up condition under throttle conditions so the trim system limits are designed to account for that. And there is a point at max trim and high speed where the force requires on the yoke and/or the manual trim wheel is too great to physically overcome. I would imagine high speed, max down trim and then maybe cutting the throttles back would be the worst case condition.

I had forgotten that the data from the 2nd crash wasn’t shared. I’m guessing it was not favorable for pilot response judgement and therefor not favorable to the anti-Boeing / anti 737-MAX narrative. That’s speculation on my part for sure.

And to repeat, I’m not absolving Boeing of any or all responsibility, but I do recognize that most every crash is due to the Swiss cheese equation. There are instances where a series of holes line up and you can see through a stack of Swiss cheese. It’s rare, but it can happen. The goal of the engineers are to put enough layers of “cheese” or shrink those holes to the point that it never happens.

 

Hmm....I didnt look at what info was available super close but based on what you 2 said I wonder if they got fast enough to tuck the plane...Mach Tuck. Combined with the trim the wrong way probably no way to un trim it or pull out.

Hey Gino...does Boeing publish a critical mach number for the max? Have you heard of anyone every having control issues at high mach number on a 737 if they overspeed? I am curious how close barber pole is to whoah...what the hell why wont the elevator work.

Actually do the glass planes even have an actual barber pole anymore?

 

All they needed was a functional treadmill.

 

Mach crit is around .80, the shock wave first forms on the cockpit roof. Limit is .84

quick explanation of Mach tuck- supersonic airflow begins on the wing before the whole airplane goes supersonic- as the aircraft continues to accelerate, the shock wave forms and moves the center of lift aft- causing a pitch down moment. Mach trim moves the stabilizer to compensate. All modern jets fly in this “transsonic” range. Flying too far past the redline in the Mach regime can lead to unrecoverable nose down situation.

Mach tuck is a factor for the 737 family. I remember flying the old -300, no autothrottles and round dials for airspeed. I got into the first rumble of Mach buffet a few times by accident, with no discernible effects of Mach tuck, although with the Mach trim compensating, you probably wouldn’t until very far into the over speed range. Point being, you’d have to fly pretty far into the Mach buffet with the airplane shaking like hell before the tuck got real bad- however that is all at high altitude where it can happen fast. Mach region at low altitude is a lot faster, so it may not have been s factor in the Ethiopian crash. We just don’t know.

geting to full nose down trim takes a long time, they had to be ignoring the running trim wheel for quite a while. And even with MCAS running, it can be reversed with the thumb mounted trim switch, like the Lion Air Captain did for several minutes. So they were likely in very far over their heads. Sad.

like I said, I wouldn’t wish any of these scenarios on my worst enemy, but the airplane can be flown. You have to get the damn thing away from the ground and work out some checklists.

Look at Emirates 231 from December- 777 takeoff from Dubai, failed to pull the nose up for a normal takeoff because the automation didn’t tell them to. Accelerated to 280 knots (past the flap and gear redline) at 50 feet altitude, skimming the rooftops. At one point the captain pushed the nose over manually, at 200’ above the ground, because the automation told him to! Finally someone with half a brain pulled back into a normal climb attitude.

again we’ll never know, since no one was hurt, no metal bent, so no accident report. They continued on to Washington DC, so the voice recorder was overwrittten. Emirates has the flight data from the recorder, think they turned it over? Fired all 4 crew on their return to Dubai. This crap happens all the time at these third world carriers and we never hear anything.

Now, enough flying nonsense- let’s talk about Daytona!!!