This is reminding me more and more of that ValuJet crash. They were an airline rather than a manufacturer, but there was more to the story than just the crash and they had had a pattern of safety incidents and cutting corners before the fatal one that woke everyone up. The Atlanta local media fell asleep and bought into the idea that the airline was somehow a victim, and it took reporting by national papers to uncover the truth. The FAA also had looked the other way on far too much.
Not long after the airline restarted it had a merger and decided the ValuJet name just had to go (and it became AirTran). I think we'll also see the whole MAX 8/MAX 9 name wiped from the face of the earth. Boeing will do some kind of retrofit on every plane and just rename the model (737-1000?) Max will be put into total retirement and become a non-person at Boeing headquarters. |
Originally Posted by LarryJ
(Post 30929726)
There is no time to stop and think about the possible causes of the runaway and, if you somehow figured it out, it wouldn't help you.
The other systems which also control stabilizer trim, and have the potential to cause a runaway, are the electric trim system, autopilots (there are two), and the speed trim system. All of those have been part of the 737 since it first flew more than 50 years ago. https://www.nytimes.com/2019/03/25/b...ion-error.html (bolding mine) During flight simulations recreating the problems with the doomed Lion Air plane, pilots discovered that they had less than 40 seconds to override an automated system on Boeing’s new jets and avert disaster. ... The pilots, in the simulations, followed such procedures to successfully shut off the system and land safely. But they did so with a far better understanding of how it worked and prior knowledge that it would be triggered — benefits that the pilots of the fatal 737 Max crashes did not have. If pilots don’t act hastily enough, attempts to disable the system can be too late. In the Lion Air crash, pilots used the thumb switch more than two dozen times to try to override the system. The system kept engaging nonetheless, most likely because of bad readings from a sensor, until the plane crashed into the Java Sea, killing all 189 people on board. ... In the current design, the system engages for 10 seconds at a time, with five-second pauses in between. Under conditions similar to the Lion Air flight, three engagements over just 40 seconds, including pauses, would send the plane into an unrecoverable dive, the two people involved in the testing said. The information I've seen to date also makes me think that Boeing cut the margin of safety far, far, far too thin when it comes to the 737-Max and the MCAS software. |
Originally Posted by Plato90s
(Post 30930299)
"There is no time" is a good choice of words, as this NYT article suggests
The information I've seen to date also makes me think that Boeing cut the margin of safety far, far, far too thin when it comes to the 737-Max and the MCAS software. It's also not unique to 737s. Every transport jet, and some of the G.A. airplanes, that I've flown have had a runaway trim procedure that I've had to know and practice. If aircraft systems have the ability to trim the airplane, and they must, then a runaway trim situation is possible. The runaway stab procedure in the 737 is comparable to turning on your hazard lights in your car when you suddenly have to stop on a freeway. It literally takes less than five seconds to think about it then do it.
Originally Posted by osamede
(Post 30930561)
These pilots dont think so:
Instead, you should compare my argument to theirs and judge both on their merits. I have explained why knowing more about MCAS does not help in handling an unscheduled MCAS activation. What have these other authorities said that convinces you that my arguments are wrong? |
Originally Posted by LarryJ
(Post 30931198)
Runaway trim has been a thing ever since we started using powered trim systems in the 1940s. MCAS doesn't change that. Actually, an MCAS runaway is slower, due to it's 5-sec pauses, than any of the other probable trim runaways. That gives you more time than you would have had for any of the runway trims that we trained for over the past 6+ decades.
Originally Posted by LarryJ
(Post 30931198)
Instead, you should compare my argument to theirs and judge both on their merits.
My view is that is a technically correct answer which does not alter the fact that the primary reason over 350 people are dead is due to bad choices by Boeing. They prioritized the ability to sell the aircraft with the promise of no-retraining against the safe operation of a passenger jet. |
Originally Posted by chipmaster
(Post 30914049)
3) Third world ( sorry just the expression ) likely minimal to no training on differences, less experience, less hours, etc. etc. and as we now learn planes with optional safety features NOT purchased The "optional" safety feature is a disgrace for Boeing, it seems someone has seen Nickel-and-Diming at rental cars and felt it was an appropriate way for an aircraft manufacturer. The UK Trident jet more than 50 years ago had AOA comparison as standard. I wonder if the FAA knew it was being offered as an option rather than standard, seeing as all the trial aircraft were for airlines who have ordered it. And I wonder what other safety features had been made optional, I somehow can't see this being the sole one. It's also curious that the whole MCAS thing seemed to develop during certification, rather than being original design concept, and by the time it was done and these additional warnings were needed, both the airlines in question had already signed contracts for it. 5) At least with Lion Air we now know they failed to fix the mechanical issue that resulted in repeated issues
Originally Posted by LarryJ
(Post 30931198)
Runaway trim has been a thing ever since we started using powered trim systems in the 1940s. MCAS doesn't change that.
In fact, given that you are established aircrew, can I please ask a question. Given that there are apparently few/no Max-specific simulators around, and training is on the supposedly-similar 737-800 ones, how often have you been given a training simulation with Spurious Stick Shaker PLUS Spurious Stall Warning PLUS Unreliable Airspeed indication PLUS Runaway Trim, all at the same time ? |
SWA 737 Max emergency landing
https://www.orlandosentinel.com/news...326-story.html |
Originally Posted by Plato90s
(Post 30931246)
I would suggest that the behavior of MCAS was so unexpected that the pilots didn't recognize the problem properly.
Originally Posted by WHBM
(Post 30932192)
Notably the switch to turn off MCAS has different labels to the comparable switch in the 737-800
Given that there are apparently few/no Max-specific simulators around, and training is on the supposedly-similar 737-800 ones, how often have you been given a training simulation with Spurious Stick Shaker PLUS Spurious Stall Warning PLUS Unreliable Airspeed indication PLUS Runaway Trim, all at the same time Read QF32. It is the autobiography of the Captain of QF32 which was a QANTAS A380 departing Singapore that had an uncontained engine failure which damaged every major system on the airplane. He recounts the flight in great detail, including the exact times of compound problems that you've described, and how they dealt with them. I have had an AoA vane failure in a 737-700. It produced "IAS DISAGREE", "ALT DISAGREE", and "ALTN" on both engine's EECs. One primary airspeed indicator dropped to minimum (45kts) and the same-side's altitude display was wrong. We quickly verified which flight instruments were correct, ensured that the pilot-flying was the one with the good instruments in front of him, priorities the checklists for each indication and accomplished them in that order, and landed. I met that Captain for the first time 60 minutes before the flight on which all of that happened. Made for an interesting flight but it is exactly what we are trained to do even though neither of us had every been given that exact combination of problems in the simulator. |
Originally Posted by LarryJ
(Post 30933864)
There is no difference in the stab trim cutout switches. (Where did you see that reported?)
https://www.pprune.org/10429289-post155.html |
Originally Posted by hull22
(Post 30932980)
SWA 737 Max emergency landing
https://www.orlandosentinel.com/news...326-story.html |
Originally Posted by tmorse6570
(Post 30934814)
This plane obviously has problems.
|
4 Attachment(s)
Originally Posted by WHBM
(Post 30934187)
Originally Posted by LarryJ
(Post 30933864)
There is no difference in the stab trim cutout switches. (Where did you see that reported?)
https://www.pprune.org/10429289-post155.html |
Originally Posted by TWA884
(Post 30935459)
Other than the angle from which the photos were taken, those appear to be identical (the MAX panel is on the right).
|
An interesting read: https://www.eetimes.com/document.asp?doc_id=1334482
My simply distillation
Now the CEO and senior leaders should take a look at what JnJ did with their Tylenol and or Intel finally had to do with their FDIV. It is hard to admit you failed, but the longer they don't the worse it will be and all confidence will be lost. Of course AirBus can't look itself cleanly in the mirror as their closet isn't clean of skeletons either. |
Originally Posted by WHBM
(Post 30934187)
There are side-by-side photos of the switch units from the -800 and the Max in the substantial PPRuNe thread on the event.
https://www.pprune.org/10429289-post155.html Are you saying that the slight change in labeling is a factor? |
Just to help, the "identical" switches are labelled :
737NG : MAIN...........AUTO ELECT..........PILOT 737Max : PRI...........B/U |
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