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Boeing 737 MAX 8 Crashes: Lion Air & Ethiopian Airlines

 
Old 03-12-2019, 03:19 PM
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Boeing historically underpays their employees and they have a huge gap between senior and junior engineers
I wonder if the have attrition or competence in their software teams related to this
I also wonder if aerospace has tight requirements like auto
I imagine so, but it seems they have less rigorous regulations
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Old 03-12-2019, 03:47 PM
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40k (or is it 31k...) flights with southwests 737 Max 8s, they claim no issues




edit: 40k per their statement I found here.
https://www.khon2.com/news/local-new...hts/1841677155

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Old 03-12-2019, 03:49 PM
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Going on vacay in 2 months and flying AA. Luckily it is a 737-800.
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Old 03-12-2019, 03:55 PM
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Originally Posted by imj0257 View Post
Going on vacay in 2 months and flying AA. Luckily it is a 737-800.
We'll miss your french fry posts
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Old 03-12-2019, 05:21 PM
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Boeing sucks balls, as does Lockheed Martin.
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Old 03-13-2019, 10:39 AM
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Originally Posted by Majofo View Post
We'll miss your french fry posts
I leave Friday morning so I'll make sure to get the fries in before I leave.
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Old 03-13-2019, 10:42 AM
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Old 03-13-2019, 10:42 AM
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Old 03-13-2019, 11:39 AM
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https://www.wsj.com/articles/pilot-o...ms-11552473593

Pilot of Crashed Ethiopian Airlines Jet Reported Flight-Control Problems

March 13, 2019

ADDIS ABABA, Ethiopia—The pilot of the Ethiopian Airlines jet that crashed Sunday reported that he was having flight-control problems and wanted to return to the airport, but didn’t indicate any other technical faults or other difficulties during the jet’s short ascent, according to the carrier’s chief.

In an interview with The Wall Street Journal, Chief Executive Tewolde Gebremariam declined to discuss the flight or the crash investigation further, but said the conversation between the pilot and ground control didn’t point to any external issues, like a bird collision, that might help investigators narrow the possible causes. The pilot “reported back to air-traffic controllers that he was having flight-control problems” and wanted to return to Addis Ababa, Mr. Gebremariam said.

In the Indonesian crash, investigators are focusing on flight-control issues during its 11 minutes in the air, as well as probing maintenance and the actions of the plane’s pilots. Investigators are still months from a final conclusion.

The general similarities between the two crashes—both involved brand new MAX 8s that went down shortly after takeoff—have prompted increased scrutiny of the jet. Boeing has stood by the safety of the plane in the face of a wave of global groundings, passenger unease and calls by flight crew unions and American politicians to consider parking the jet.

Wednesday, Canada became the latest nation grounding the plane. Transport Minister Marc Garneau said, effective immediately, all Boeing 737 MAX 8 and MAX 9 aircraft cannot arrive, depart or fly over Canadian airspace.

Aviation-safety authorities in more than 30 countries have announced plans to ground the 737 MAX. The U.S. Federal Aviation Administration, the principal regulator for Boeing planes, reiterated Tuesday that the aircraft is safe, and no American operator has grounded the plane.

Hong Kong, Vietnam, Thailand, New Zealand and Lebanon on Wednesday joined regulators from China to Europe in grounding the plane after the Sunday crash in Ethiopia.
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Old 03-13-2019, 01:39 PM
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Just got a breaking new alert on my phone from a local news station that Pres Trump has ordered an immediate grounding of all 737 Max 8 and 9 jets..........
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Old 03-13-2019, 01:53 PM
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Old 03-13-2019, 01:54 PM
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Check your flights!!

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Old 03-13-2019, 01:54 PM
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Old 03-13-2019, 01:59 PM
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https://whdh.com/news/trump-orders-i...thiopia-crash/

WASHINGTON (AP) — President Donald Trump says the U.S. is issuing an emergency order grounding all Boeing 737 Max 8 and Max 9 aircraft in the wake of a crash of an Ethiopian Airliner that killed 157 people.

Many nations in the world had already barred the Boeing 737 Max 8 from its airspace, but until now, the Federal Aviation Administration had been saying that it didn’t have any data to show the jets are unsafe.

Trump said Wednesday that the FAA would be making the announcement soon to ground the planes.

He says any plane currently in the air will go to its destination and then be grounded.

Trump says pilots and airlines have been notified.

He says the safety of the American people is of “paramount concern.”
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Old 03-13-2019, 02:49 PM
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You might hate him, but kudos for this
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Old 03-13-2019, 02:50 PM
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Old 03-13-2019, 02:58 PM
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Originally Posted by Majofo View Post
You might hate him, but kudos for this
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Old 03-13-2019, 08:12 PM
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Originally Posted by Majofo View Post
You might hate him, but kudos for this
Agreed.

But interestingly, I had no idea POTUS/executive branch had this kind of power. I always thought FAA was the final say on grounding planes....interesting.
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Old 03-13-2019, 08:16 PM
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He probably couldn't unilaterally order them back up in the air, but grounding for public safety? Why not?
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Old 03-13-2019, 08:22 PM
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Agreed. He has the ability to shut down US airspace. This is far less intrusive.
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Old 03-13-2019, 08:36 PM
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https://www.faa.gov/news/updates/?newsId=93206
Originally Posted by FAA
The FAA is ordering the temporary grounding of Boeing 737 MAX aircraft (PDF)operated by U.S. airlines or in U.S. territory. The agency made this decision as a result of the data gathering process and new evidence collected at the site and analyzed today. This evidence, together with newly refined satellite data available to FAA this morning, led to this decision.

The grounding will remain in effect pending further investigation, including examination of information from the aircraft’s flight data recorders and cockpit voice recorders. An FAA team is in Ethiopia assisting the NTSB as parties to the investigation of the Flight 302 accident. The agency will continue to investigate.
Looks like FAA has seen hard data that led to this decision.
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Old 03-14-2019, 10:08 AM
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Originally Posted by nist7 View Post
https://www.faa.gov/news/updates/?newsId=93206


Looks like FAA has seen hard data that led to this decision.
Yes and no. Data collected from the crash site and satellites helped with the decision, but the black boxes only just arrived in Paris today.
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Old 03-14-2019, 02:33 PM
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https://www.cnbc.com/video/2019/03/1...el-elwell.html


Similar track data between the 2 flights drove the FAA's decision to ground the fleet. Took a few days to obtain and to run an enhancement program to decipher ADS-B raw data from the Ethiopian crash. ADS-B is the data link from the transponder transmitting via satellite link up during flight.
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Old 03-14-2019, 04:52 PM
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https://www.cnbc.com/2019/03/14/irid...stigation.html

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Old 03-14-2019, 05:42 PM
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How Boeing Sold Its 737 Max | NYT News

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Old 03-14-2019, 07:43 PM
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Originally Posted by nfnsquared View Post
FAA issued an AD in Nov, 2018 (2018-23-51) after the Lion Air Crash, but adherence to basic emergency procedures training should have prevented both accidents.

Runaway Stabilizer Trim:

1. Autopilot: Disengage
2. Stabilizer Trim Cutout Switch - Cutout


Initial and recurrent training covers all the aircraft BOLD FACE emergency procedures in addition to many other items.

This doesn't answer why MCAS is getting/perceiving faulty AOA indications. That is still an open question that the FAA and Boeing need to research/address.

There haven't been any US based accidents in MAX aircraft. What we don't know is if that's because no US based MAX 737 has run into the MCAS issue or if instances did happen, but aircrew training saved the day...I'd have to assume that the FAA and Boeing are pouring over maintenance logs and questioning MAX pilots to see if there is any record of runaway trim in US based MAX aircraft.
Another question for nfnsquared and/or others who are more familiar with aircraft flight controls in technical details.....

I assume that in many training procedures, the pilots are trained to disengage autopilot and take manual control in many instances.

Could it be possible that auto pilot is disconnected BUT for some reason the computerized systems (the MCAS) still are overriding trim or some other parts of the flight control? Aka the stabilizer trim cutout switch bolded above.

I was under the impression that autopilot OFF = total manual flying...but with how complicated/advanced modern jet aircrafts are, I assume there are sub-systems that may be automated and may need an additional step to turn off?
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Old 03-14-2019, 07:45 PM
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^ shoot the shit/water cooler analysis.


in short, yes.



we also see how quickly our skills as drivers diminish when using just level 1 autonomy in cars.
if the pilots arent constantly training for this, they wont know how to figure it out while the plane is diving.

but agreed with NFN, should fall back to the BOLD FACE

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Old 03-14-2019, 08:36 PM
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Originally Posted by nist7 View Post
Another question for nfnsquared and/or others who are more familiar with aircraft flight controls in technical details.....

I assume that in many training procedures, the pilots are trained to disengage autopilot and take manual control in many instances.

Could it be possible that auto pilot is disconnected BUT for some reason the computerized systems (the MCAS) still are overriding trim or some other parts of the flight control? Aka the stabilizer trim cutout switch bolded above.

I was under the impression that autopilot OFF = total manual flying...but with how complicated/advanced modern jet aircrafts are, I assume there are sub-systems that may be automated and may need an additional step to turn off?
Both the autopilot and MCAS can run the trim. As I understand it, MCAS is only operative with the flaps up and autopilot off. It's designed to counter-act pilot error when manually flying the jet.

Also, the MCAS runs the trim pretty slowly, at the rate of 2.7 degrees nose down over a 10-second interval. IIRC, it will wait 10-seconds and then continue to run the trim as before if it still senses that the aircraft is in a dangerous attitude.

So, no, turning the AP off will have no effect if the trim is running due to MCAS. The cutout switch will have to be used. The trim can also be stopped by using the electric trim switch in the opposite direction, but it will continue to run if you release the trim switch.

There are large manual trim wheels that can be spun by the pilots to manually trim when the trim cutout switch is activated.

If the trim is running due to erroneous AP inputs, then it should stop after disengaging the AP.

I need to go back and check, but I believe the Lion Air was flying with the AP off, hence with MCAS enabled. But I'm having trouble understanding how such a slow rate of trim could have led to a crash if MCAS is at fault. One could assume that the pilots never cut out the trim switch and the trim continued to run in 2.7 degrees down in multiple 10-second intervals? I just find it terribly hard to believe that a crew allowed that to happen.

Edit: Yeah, appears the AP was off for Lion Air. Interestingly enough, on the previous flight (in which a different crew was in the cockpit), they had stick shaker inputs and the trim running starting at 400' on takeoff. That crew used the cutout switch and trimmed manually for the rest of the flight and landed uneventfully. They wrote up the system and if IIRC, maintenance flushed the pitot-static system on one side and declared it fixed.

Last edited by nfnsquared; 03-14-2019 at 08:44 PM.
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Old 03-14-2019, 08:51 PM
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Boeing plans to fix the 737 max jet with a software update

Waiting for investigation but I still wonder why the MCAS full description was not included in 737-Max pilot training documentation before last fall's crash.

https://www.wired.com/story/boeing-7...-fix-lion-air/ .

THE INVESTIGATION INTO the crash of an Ethiopian Airlines 737 MAX 8, which killed 157 people on Sunday, is still in its earliest stages, but already regulators around the world have grounded the Boeing jet. The American FAA issued its own grounding order today, noting that, based on the wreckage and satellite-based tracking of the jet’s route, it found similarities between this crash and that of the Lion Air 737 MAX 8, which crashed in Indonesia in October, killing 189. Those similarities “warrant further investigation of the possibility of a shared cause for the two incidents that need to be better understood and addressed,” the FAA wrote.

The thing is, Boeing and the FAA had already settled on a way to address the likely cause of the Lion Air crash. And they were well on their way to implementing it when the Ethiopian plane went down.

Indonesia’s civil aviation authority hasn’t published any findings as to the cause of the Lion Air crash, but in its preliminary report, the agency examined the MAX’s Maneuver Characteristics Augmentation System, or MCAS. Boeing designed the system after discovering during flight testing that the 737 MAX engine placement—higher and farther out on the wing than on the previous generation—could pitch the plane upward in certain conditions, increasing the likelihood of a stall.​​​​​​When the MCAS detects the plane climbing too steeply without enough speed—a recipe for a stall—it moves the yoke forward, using the horizontal stabilizer on the tail to bring the nose of the plane down. “It’s a fancy name for what we used to call ‘a stick pusher,’” says Ross Aimer, CEO of Aero Consulting Experts, who is rated to fly every type of Boeing jet. It’s distinct from an autopilot system, and only kicks in when the plane is being manually flown, the way a car’s traction control activates to keep a driver from skidding out.

The problem with the Lion Air flight was the MCAS went to work when it shouldn’t have. The 737 MAX was climbing normally, but due to a faulty sensor the digital flight data recorder detected a hard-to-believe 20-degree difference in the angle of attack between the left and right sides. Over the next 10 minutes, the pilots repeatedly tried to pull the plane’s nose back up, but the MCAS kept forcing the yoke forward, pushing the plane down. Ultimately, the plane crashed into the Java Sea, killing everyone aboard.

If the pilots had known the MCAS was at fault, they could have shut down the plane’s ability to automatically adjust its trim (which determines its position in the air) so they could manually do it themselves. But they ended up “behind the airplane,” confused and trying to figure out what the computer was up to. “When you’re behind the airplane, you’re almost dead,” Aimer says.

That may be because they didn’t know the MCAS existed: In the jet’s manual, Boeing had not noted its presence. In November, The Wall Street Journal reported that the company had worried about “inundating average pilots with too much information—and significantly more technical data—than they needed or could digest.” Meanwhile, Boeing was pitching the 737 MAX to airlines as being so similar to the previous generation that pilots flying the old 737 would barely need any new training.

Soon after the Lion Air crash, the FAA issued an Emergency Airworthiness Directive, telling Boeing to update its manual and provide instructions for how to handle what happened to the Lion Air pilots. “If an erroneously high single angle of attack (AOA) sensor input is received by the flight control system, there is a potential for repeated nose-down trim commands,” it wrote.

Like most modern plane crashes, the Lion Air one was born of multiple problems. The angle of attack sensor’s incorrect reading triggered a system the pilots didn’t know existed and didn’t know how to manage. “We have this strange failure of this sensor signal, and behind it unfortunately we have a weak system implementation,” says Bjorn Fehrm, a Swedish Air Force veteran and aviation analyst with Leeham News and Analysis.

The solution, then, is twofold: Boeing started by warning airlines that the MAX’s angle of attack sensors had malfunctioned before, that such a failure could lead the MCAS to push the plane’s nose down, and that pilots could safely defuse the problem by cutting off the trim system and working the plane manually.

After making sure pilots knew about the problem and how to resolve it, Boeing would work on a longterm solution. Essentially, it would rejigger the software governing MCAS so that it wouldn’t be as prone to jumping into action based on one scary sensor reading, instead considering more data. And it would limit how many times it can engage.

Boeing said it would have it done within a few months. Then the Ethiopian Airlines jet crashed. We don’t yet know if the jet’s MCAS system is what brought the plane down, or what other factors may have been at work. We do know that what seemed a straightforward fix to an unforeseen problem is now muddied—and that the 737 MAX won’t take off again until it’s been cleared up.

Last edited by Legend2TL; 03-14-2019 at 08:53 PM.
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Old 03-14-2019, 08:59 PM
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Old 03-14-2019, 09:21 PM
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Originally Posted by nfnsquared View Post
Both the autopilot and MCAS can run the trim. As I understand it, MCAS is only operative with the flaps up and autopilot off. It's designed to counter-act pilot error when manually flying the jet.

Also, the MCAS runs the trim pretty slowly, at the rate of 2.7 degrees nose down over a 10-second interval. IIRC, it will wait 10-seconds and then continue to run the trim as before if it still senses that the aircraft is in a dangerous attitude.

So, no, turning the AP off will have no effect if the trim is running due to MCAS. The cutout switch will have to be used. The trim can also be stopped by using the electric trim switch in the opposite direction, but it will continue to run if you release the trim switch.

There are large manual trim wheels that can be spun by the pilots to manually trim when the trim cutout switch is activated.

If the trim is running due to erroneous AP inputs, then it should stop after disengaging the AP.

I need to go back and check, but I believe the Lion Air was flying with the AP off, hence with MCAS enabled. But I'm having trouble understanding how such a slow rate of trim could have led to a crash if MCAS is at fault. One could assume that the pilots never cut out the trim switch and the trim continued to run in 2.7 degrees down in multiple 10-second intervals? I just find it terribly hard to believe that a crew allowed that to happen.

Edit: Yeah, appears the AP was off for Lion Air. Interestingly enough, on the previous flight (in which a different crew was in the cockpit), they had stick shaker inputs and the trim running starting at 400' on takeoff. That crew used the cutout switch and trimmed manually for the rest of the flight and landed uneventfully. They wrote up the system and if IIRC, maintenance flushed the pitot-static system on one side and declared it fixed.
Ah I see, thanks for those insights. And that makes more sense.

The question I'm curious about is....according to Legend2TL post below, the article from Wired (and we know from other sources) that Boeing did not disclose this MCAS function to pilots and so this lack of knowledge contributed to the crash.

BUT as you have also mentioned...a prior flight crew encountered a very similar problem and they switched off the auto-trim system and trim if manually. But in this instance, this is still prior to the knowledge of the MCAS....hence it seems that the function of this auto-trim is not unique/novel to the MCAS (which IS a new feature), but it seems like the MCAS is a software-based flight safety system that can override the trim control with AP off but the cutout switch still turned on....negating manual inputs.

So I wonder if there were knowledge/training differences between flight crew since as you mentioned, two different flight crews had very similar issues but one plane landed perfectly safe but another had a horrendous crash.

And then now the Ethiopian crash....presumably that crew should also have known about this....unless investigations reveal other factors.

But one thing is still mystifying....how the altitude seems to gain/lose so fast, especially with some data from the Ethiopian flight....as you said....the trim adjustments seem to not be hugely dramatic/drastic....

Originally Posted by Legend2TL View Post
Waiting for investigation but I still wonder why the MCAS full description was not included in 737-Max pilot training documentation before last fall's crash.

https://www.wired.com/story/boeing-7...-fix-lion-air/ .
Well, at least this is very well known now...with this whole MCAS and trim malfunction bug.

In a weirdly logical way...I think the 737 MAX should be very safe to fly after they are back in the air since everyone and their dog will know about MCAS....
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Old 03-14-2019, 09:32 PM
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Originally Posted by oo7spy View Post
As an engineer, this is my worst nightmare: that a decision I make will affect someone else’s life in a harmful manner.
I'm not an engineer (and I guess I am Monday morning QBing here) but if that MCAS gets two different AOA readings from two different sensors with that Lion Air plane....my thought would be to program an auto-disengage/shutoff where if the automated sensors are potentially compromised or have conflicting data from two sensors that's supposed to read only one data point...then all controls revert back to the pilots and maybe display some kind of warning light.

But then again the MCAS is designed to exactly override manual control because sometimes human control = almost certain death.

I wonder how much back testing they did before they rolled it out. Since they decided not to inform pilots regarding the MCAS as it was being rolled out, they should've tried to simulate tons of possible scenarios with pilots that had no knowledge of the MCAS + potential system malfunction/stress events and see how pilots would react and how the system would react. And now that I think about it...this detail could likely come to surface (along with possible management issues or trying to speed up roll out of the new plane by omitting this feature which likely would delay roll out?) years down the road in law suit filings....

We could also find culpability in the management/administration/bean counters at Boeing....potentially even more so than the engineers....if they find corners were cut to try to speed up 737 MAX rolling out or....even a case like the Challenger disaster where some engineers could see an issue but management over-rode their concerns....

Last edited by nist7; 03-14-2019 at 09:34 PM.
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Old 03-14-2019, 09:43 PM
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The problem with my job that I have discovered over the years is that I don’t know what I don’t know, and that is the most dangerous part of my job. Until the point your idea is proven faulty or perfect with empirical evidence through millions of trials (literally one in a million instances), no amount of peer review or experimentation can predict that result. Only mass production can.

I am not an aerospace engineer. I am well aware of automotive grade electronic qualifications and understand military and space grade specifications exist beyond that. I would hope aircraft qualification standards exceed automotive, but I’m not familiar with the industry. Regardless of the spec though, random system failures WILL happen regardless of if man made the system or nature did.

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Old 03-14-2019, 10:06 PM
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Originally Posted by oo7spy View Post
The problem with my job that I have discovered over the years is that I don’t know what I don’t know, and that is the most dangerous part of my job. Until the point your idea is proven faulty or perfect with empirical evidence through millions of trials (literally one in a million instances), no amount of peer review or experimentation can predict that result. Only mass production can.

I am not an aerospace engineer. I am well aware of automotive grade electronic qualifications and understand military and space grade specifications exist beyond that. I would hope aircraft qualification standards exceed automotive, but I’m not familiar with the industry. Regardless of the spec though, random system failures WILL happen regardless of if man made the system or nature did.
Yeah that's definitely a good point. I also would assume aerospace engineering...especially systems/products deployed on a wide scale for mass commercial consumption...would have quite strict and rigorous standards of testing. But just like you said...we are ignorant of what we don't know. There are trillions of possible combination of factors/variables that indeed it may not be practical or even possible to discover until it is rolled out into the real world.

Though I would assume engineers over there have some kind of set of common error/system-fault protocol they introduce when testing a new hardware/software to see how the product reacts and/or even how pilots would react.

With a system like MCAS, it seems somewhat obvious that one of the most critical sensor component is the AOA sensor, and so they would test how the system would react to erroneous/botched AOA inputs as well as try to simulate how pilots would react to that and then the system's reaction to the pilots reaction.....but again...all hindsight is 20/20 and monday morning QBing here....though I'm sure lawyers are gonna be digging into this and we'll likely see more details emerge down the road in court documents....

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Old 03-14-2019, 11:14 PM
  #75  
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Fuck Boeing.
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Old 03-14-2019, 11:22 PM
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Well, we're all biting off on MCAS as a cause, but no one knows for sure at this point.

Since Boeing was forced to create MCAS as a "stop gap" to meet certification, they didn't want that fact to be widely known? Dunno.
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Old 03-14-2019, 11:47 PM
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Originally Posted by gatrhumpy View Post
Fuck Boeing.
If it shines; ship it!
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Old 03-15-2019, 03:22 PM
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Yesterday I was texting with my brother who works at Boeing on the 737 (not an engineer, works in delivery/scheduling/timelining) and in the middle of our text he says "hang on, have to reprogram the 737 MCAS... [ABABLEFTRIGHTLEFTRIGHTUPDOWNUPDOWNSTART]"...

I admit it, I laughed.
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Old 03-15-2019, 04:43 PM
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Originally Posted by stogie1020 View Post
Yesterday I was texting with my brother who works at Boeing on the 737 (not an engineer, works in delivery/scheduling/timelining) and in the middle of our text he says "hang on, have to reprogram the 737 MCAS... [ABABLEFTRIGHTLEFTRIGHTUPDOWNUPDOWNSTART]"...

I admit it, I laughed.
Hmm. Maybe that is why there are reports that the plane was traveling much faster than expected.

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Old 03-15-2019, 07:58 PM
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Originally Posted by stogie1020 View Post
Yesterday I was texting with my brother who works at Boeing on the 737 (not an engineer, works in delivery/scheduling/timelining) and in the middle of our text he says "hang on, have to reprogram the 737 MCAS... [ABABLEFTRIGHTLEFTRIGHTUPDOWNUPDOWNSTART]"...

I admit it, I laughed.
He forgot to hit SELECT.

Now we know why it's all messing up......
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