Author Topic: More MAX information  (Read 34184 times)

Offline Oldman731

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More MAX information
« on: March 15, 2019, 10:21:26 AM »
https://www.aopa.org/news-and-media/all-news/2019/march/14/faa-grounds-boeing-737-max-fleet?utm_source=epilot&utm_medium=email&utm_content=tts&utm_campaign=190314epilot

Some details that those of us who aren't 737 pilots should find interesting.  Heck of a thing to have happen just after takeoff.

- oldman

Offline Puma44

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Re: More MAX information
« Reply #1 on: March 15, 2019, 10:56:42 AM »
Here’s a bit more logical explanation from one who actually flys the 737Max:

The secret life behind the cockpit door. Rob Graves, an airline Captain, betrays the profession telling all the details of what it's like to be an airline pilot from dodging thunderstorms to life in hotels.
Thursday, March 14, 2019
What's Next for the Max?






As an aviation blogger, the past few days have been simultaneously hope inspiring and depressing. Hope inspiring as many people understand, or make a good faith attempt to understand, the underlying issues surrounding the 737 Max. But also depressing as random fanbois, trolls, and low information, yet self proclaimed experts, happen by my comments section to disgorge their dubious wisdom on things about which they know little or nothing.

Mencken was Right: No One Ever went Broke Underestimating the Intelligence of the Public

One commenter offered, based on no information other than two 737s had crashed, that all of them should be grounded. I pointed out that by that logic, it would be even more beneficial to ground all airplanes everywhere as it would be safer still. The response was "I didn't say all airplanes should be grounded" displaying an ironclad grip on logical fallacies.

When I noted that the MCAS system could be completely deactivated using two switches mounted on the center console, a commenter replied that well, "maybe the switches reconnected themselves". Other than the testing of those switches being a mandatory preflight item, this commenter has obviously confused the Boeing 737 with the SkyNet model T-1000 Terminator which can rewire itself automatically.

Lastly, when one commenter [Hi Scott!] boldly opined that the 737 was the worst airplane he'd ever flown on, I replied that my passenger experience is usually more dependent upon the particular airline and class of service rather than the aircraft type. This big brained person assured me, however, that no, none of that mattered. He apparently would rather sit in a non reclining 28 inch pitch economy seat on a Spirit A320 than a first class seat on a JAL 737.  [Sigh]

Public Relations and Marketing Wins

So the FAA bowed to international and media pressure and grounded all Max aircraft, which is proving to be a minor inconvenience to most operators of the aircraft. I was personally walking out to a Max to fly to Phoenix when the announcement came. Someone somewhere had done some preparations and an -800 was towed to the gate by maintenance about 10 minutes later for a slightly delayed departure.

We of course are now treated to the circular logic of all the "I told you so" stories. The process starts as media sensationalism whips up a gullible and credulous public followed by outraged calls for the aircraft to be grounded. After weather-vaning politicians cave into public pressure, preening media talking heads then get to state that something must have been really been wrong. And so it goes.

Make no mistake: this grounding has more to do with public relations and marketing than safety. As of yet, there is very little evidence that the two Max crashes are in any way related other than the most superficial of circumstances. But the tsunami of media scare stories and sensationalism showed no signs of abatement, so this was the correct decision.

The FAA cited "newly" discovered satellite data which finally swayed their decision.They are referring to the ADS-B tracking system which relays flight parameters to air traffic control through satellite. This information, however, was publicly available shortly after the crash and it does show some minor altitude excursions, though nothing is conclusive.

The cockpit voice recorder and flight data recorder from the Ethiopian crash have been recovered and sent to France for analysis. Again, prescient commenters noted that this was a good thing because, of course, had they been sent to the US, American investigators would falsify any result finding the US producer of the aircraft at fault. I actually agree with this decision in spite of the slander against the integrity of the NTSB and other US investigators. Having French investigators analyze the data will deflect the inevitable cries of bias should the investigation find fault in anything except the aircraft itself.

What Next?

What happens next is we wait for the data from ET302 to be downloaded and released. When that happens and a likely cause of the accident can be discerned, the Max will be cleared to fly. Notice that I didn't say that this clearance will in any way be dependent on the outcome of the investigation. The aircraft will be flying again in a matter of weeks regardless of the findings.

Why you ask? Should the MCAS system be implicated in this crash (unlikely in my opinion), there will be software fixes and training updates offered. As I've noted many times, the system can be deactivated completely through the use of two center console mounted switches. Even then, the system should only activate in the case of gross pilot negligence resulting in an aerodynamic stall or, as in the case of the Lion crash, an errant sensor input due to a mechanical malfunction.

The software fixes will preclude the activation of the system due to the failure of a single sensor. The training updates will reemphasize to all operators that undesirable electric trim inputs can be inhibited through the use of the center console mounted stab cutout switches.

Should the MCAS system not be implicated in the ET302 crash, the Max will be back in the air that much sooner. Make no mistake, all airline crashes are tragedies of the highest order for everyone involved. The object of any investigation is to find out what happened and to take measures to prevent any future recurrence. Commercial aviation is one of the safest, if not the safest means of transportation available.

What will be left is a mopping up by the lawyers.


Captain Rob Graves is a veteran airline pilot and retired Air Force officer. He currently flies a Boeing 737 for a major American airline where he has over 25 years of experience. His Air Force career included instructing future USAF pilots in the T-37 primary jet trainer, aerial refueling in the KC-135 Stratotanker, and conducting worldwide logistics in the C-5 Galaxy cargo aircraft. He is the author of This is Your Captain Speaking, an aviation blog. It can be found at robertgraves.com. He also writes for Avgeekery.com.






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Offline Puma44

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Re: More MAX information
« Reply #2 on: March 15, 2019, 11:10:58 AM »
https://www.aopa.org/news-and-media/all-news/2019/march/14/faa-grounds-boeing-737-max-fleet?utm_source=epilot&utm_medium=email&utm_content=tts&utm_campaign=190314epilot

Some details that those of us who aren't 737 pilots should find interesting.  Heck of a thing to have happen just after takeoff.

- oldman

Yeah, it would definitely be surprising.  Hard to get past the idea of disconnecting the technology and just hand fly the aircraft.
« Last Edit: March 15, 2019, 11:45:44 AM by Puma44 »



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Offline ACE

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Re: More MAX information
« Reply #3 on: March 15, 2019, 11:32:17 AM »
Good read. The FAA still made the right decision. I’m sure they’ll have a fix very shortly.
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Offline Puma44

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Re: More MAX information
« Reply #4 on: March 15, 2019, 11:45:04 AM »
Once the FACTS are know, a procedural and/or physical equipment change will most likely fix the issue.  My guess is a procedural change, since Boeing initially chose to keep the MCAS a secret.  Once the politicians and internet experts get out of the way, the MCAS issue can get resolved.



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Offline Zimme83

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Re: More MAX information
« Reply #5 on: March 15, 2019, 12:30:52 PM »
There are quite a lol of similarities between the crashes. The flight profile is one and They have also found parts at the crash site suggesting that the elevator was trimmed in a nose down position at the crash.  Boeing have already been working on a fix so they are apparently aware of that there are issues with the MCAS.

MCAS is supposed to handle pitch up tendencies at high AOA caused by the engines on the MAX and from what ive read Aviation authorities, for ex the Chinese, didnt like the idea that the fix was to disable the MCAS by switching auto trim off since MCAS was crucial to allow the MAX to be flown by NG certified pilots without a new type rating. (short version)

Whats also an issue is the reports of pitch down tendencies with AP engaged. The MCAS isnt active with AP on so there might be more issues that arent known yet.

From an engineering standpoint the MCAS seems to be a horribly bad design. It relies on a single sensor so it has a single point of failure and it cannot identify a sensor failure. And to make it worse a sensor failure causes the plane to behave erratic and there is no limit to how much it can trim the nose down.

But what bothers me most is the fact that runaway trims arent that unheard of. And The Ethiopian pilots for sure where aware of the issue. If the only thing needed to fix the issue is flipping a switch then i doubt that they would have crashed since thats how pretty much all airliners handle runaway trims. At this point its mostly speculations but it feels that its more into this than just a faulty AOA sensor.
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Offline Puma44

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Re: More MAX information
« Reply #6 on: March 15, 2019, 12:46:54 PM »
For consideration: “If the only thing needed to fix the issue is flipping a switch then i doubt that they would have crashed since thats how pretty much all airliners handle runaway trims.”

With the higher level of technology of the NG, it was not uncommon during initial experience with the jet for crews to say “Why’s it doing that?” because experience in the jet had not matured.  That short delay of figuring out what was going could have come into play during the initial climb phase where there tends to be a lot going on, caused a distraction, and delay in response time to correct the malfunction.

Then, there are a host of non technology related distractions that could have been a factor.

Just some thoughts.  The factual evidence from the black boxes and CVR certainly be interesting.



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Offline Vraciu

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Re: More MAX information
« Reply #7 on: March 15, 2019, 12:57:05 PM »
Once the FACTS are know, a procedural and/or physical equipment change will most likely fix the issue.  My guess is a procedural change, since Boeing initially chose to keep the MCAS a secret.  Once the politicians and internet experts get out of the way, the MCAS issue can get resolved.

My friends at United say they've known about MCAS from day one. 

Even without it, the procedure for a stab trim runaway is the same.  It doesn't matter if the MCAS is the cause or not. 

Trump did this to take the pressure off Boeing, but it was not a decision based on anything but optics.   
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Offline Vraciu

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Re: More MAX information
« Reply #8 on: March 15, 2019, 12:58:39 PM »
There are quite a lol of similarities between the crashes. The flight profile is one and They have also found parts at the crash site suggesting that the elevator was trimmed in a nose down position at the crash.  Boeing have already been working on a fix so they are apparently aware of that there are issues with the MCAS.

MCAS is supposed to handle pitch up tendencies at high AOA caused by the engines on the MAX and from what ive read Aviation authorities, for ex the Chinese, didnt like the idea that the fix was to disable the MCAS by switching auto trim off since MCAS was crucial to allow the MAX to be flown by NG certified pilots without a new type rating. (short version)

Whats also an issue is the reports of pitch down tendencies with AP engaged. The MCAS isnt active with AP on so there might be more issues that arent known yet.

From an engineering standpoint the MCAS seems to be a horribly bad design. It relies on a single sensor so it has a single point of failure and it cannot identify a sensor failure. And to make it worse a sensor failure causes the plane to behave erratic and there is no limit to how much it can trim the nose down.

But what bothers me most is the fact that runaway trims arent that unheard of. And The Ethiopian pilots for sure where aware of the issue. If the only thing needed to fix the issue is flipping a switch then i doubt that they would have crashed since thats how pretty much all airliners handle runaway trims. At this point its mostly speculations but it feels that its more into this than just a faulty AOA sensor.

Gawd forbid the crew trim nose up.   :rolleyes:
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Offline Zimme83

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Re: More MAX information
« Reply #9 on: March 15, 2019, 01:06:18 PM »
The selling point is that no additional training is needed for a NG pilot to fly a MAX so its natural that pilots expect it to be like the NG. And even if it is just a matter of training its still an issue. The same pilots are flying NEO:s and NG:s all over the world and none of them have fallen out of the sky in the same manner.

Grounding the MAX is the right thing to do, even if we dont know what happened. Not knowing is sometimes reason enough, we dont know at this point what happened or if the plane is safe and that in itself is a reason for grounding. If it was a landing accident or something like that it would probably been a different matter. But planes crashing due to loss of control so soon after take off isnt anything you can expect.

Lets hope that they find the issue and that its easy to fix because it will be a hard blow for Boeing to have the MAX grounded for any longer time.
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Offline Puma44

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Re: More MAX information
« Reply #10 on: March 15, 2019, 01:21:41 PM »
The selling point is that no additional training is needed for a NG pilot to fly a MAX so its natural that pilots expect it to be like the NG.

Fact is, there is additional training for the MAX, just like there was for the NG.  There are differences but, within the scope of the 737 Type Rating.

No professional, logically thinking pilot would expect it to fly like an NG.  Opinion and conjecture doesn’t equal fact. 

It still hasn’t been factually determined that the MCAS was the cause.
« Last Edit: March 15, 2019, 01:23:50 PM by Puma44 »



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Offline Zimme83

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Re: More MAX information
« Reply #11 on: March 15, 2019, 01:24:28 PM »
Fact is, there is additional training for the MAX, just like there was for the NG.  There are differences but, within the scope of the 737 Type Rating.

No professional, logically thinking pilot would expect it to fly like an NG.  Opinion and conjecture doesn’t equal fact.

And at least the Ethiopian pilots had additional training on the MAX including MCAS but apparently it didnt save them.
''The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge'' - Stephen Hawking

Offline Puma44

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Re: More MAX information
« Reply #12 on: March 15, 2019, 01:33:37 PM »
And at least the Ethiopian pilots had additional training on the MAX including MCAS but apparently it didnt save them.

Are you saying other MAX pilots worldwide didn’t have additional MAX training?  Are you saying the MCAS was the cause of the Ethiopian crash?  If so, how did you gain access to the black box and CVR data?
« Last Edit: March 15, 2019, 02:19:21 PM by Puma44 »



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Offline Zimme83

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Re: More MAX information
« Reply #13 on: March 15, 2019, 01:35:51 PM »
Are you saying other MAX pilots worldwide didn’t have additional MAX training?  A you saying the MCAS was the cause of the Ethiopian crash?  If so, how did you gain access to the black box and CVR data?

No im not saying any of that. In fact i doubt that the MCAS (at least alone) was the cause.
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Offline Puma44

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Re: More MAX information
« Reply #14 on: March 15, 2019, 02:18:51 PM »
That’s a good starting position until the facts are known.



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