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-   -   Another brand new 737 Max crashes (http://forums.pelicanparts.com/off-topic-discussions/1023264-another-brand-new-737-max-crashes.html)

Jeff Higgins 03-18-2019 06:39 PM
Quote:
Originally Posted by madcorgi (Post 10395744)
Grand jury has started looking at the certification process. I recall (un)fondly what it was like to receive a grand jury subpoena at Boeing. Sends everyone into ass-covering mode.
Yikes. I never had the pleasure. FAA, JTSB, and other regulatory agency audits were enough for me.

Boy, you know, it's getting harder and harder to defend these guys. There were a few pretty big scandals while I was there, and a few folks went to prison over them, but none involved loss of life and airplanes auguring in. I really hope they get to the bottom of this and, if there were any behind the scenes shenanigans regarding quality, suppliers, training requirements, certification requirements, etc., heads really need to roll.

I feel for the engineering, technical, and mechanical folks at the company. In the past (and I bet once again) these kinds of colossal FUBARs consistently emanated from the "business" end of the business - the money men. The ones trying to cut corners and "maximize shareholder (or is that "stakeholder"?) value". The guys constantly telling the guys who design and build the damn airplane to find a cheaper way. Such were the bane of my existence. If this proves to be another one of their cost cutting mandates, I hope everyone involved gets their just deserts. :(

Fly Mach .86 03-18-2019 08:03 PM
It's always a lot cheaper to modify an existing design than come up with and get a new design through the certification process. When you start modifying an original design it can and does profoundly change the flying characteristics of the airplane. The original 727-100 was a good handling airplane. The -200 was stretched and many say didn't handle quite as well as the -100. Not terribly bad but just different. I flew the original 747-100 design and it flew much better (like flying a huge Beechcraft) than the -200 imho. The -200 was a better airplane but didn't handle as nice as the original design. The worst example of this was the DC-8. The original design flew quite nice. They even flew one supersonic ON PURPOSE!! I flew the stretched -71 and -73 models and it was the most difficult airplane I have ever flown. It had been stretched more than once, re-designed wings and re-engine a few times. I don't think the original 737 design needed MCAS. If this was an MCAS software problem I surely hope it can be fixed properly. Soon.

kach22i 03-19-2019 07:24 AM
Quote:
Originally Posted by Fly Mach .86 (Post 10395984)
It's always a lot cheaper to modify an existing design than come up with and get a new design through the certification process. When you start modifying an original design it can and does profoundly change the flying characteristics of the airplane.
Reminds me of this fiasco below.

2013
Coast Guard to decommission troubled 123s
https://www.militarytimes.com/2013/03/20/coast-guard-to-decommission-troubled-123s/
Quote:
The eight vessels were the produced under a contract to convert the Coast Guard's 49 110-foot patrol boats into 123-foot vessels.
I don't know who else caught the pilot union representative on NPR yesterday afternoon/last night, but the Boeing self-certification process didn't serve the public or the pilots very well this time. :eek:

widebody911 03-19-2019 07:26 AM
https://www.seattletimes.com/business/boeing-aerospace/failed-certification-faa-missed-safety-issues-in-the-737-max-system-implicated-in-the-lion-air-crash/

kach22i 03-19-2019 07:32 AM
Quote:
Originally Posted by javadog (Post 10395811)
Actually, I think it is described in the manual. There are not very many simulators for the Max 8 yet, but...

I’m fairly certain that a competent pilot would recognize the fact that the stabilizer trim is being manipulated without pilot input. That is something that they do train for, it really doesn’t matter why the stabilizer is moving uncommanded. The fix is the same and it’s been that way for 50 years.

I don’t mean any disrespect to the pilots that crashed these two jets but I truly believe that that would not of happened with the frontline pilots we have here in this country.
From news reports, and I'm sure this will get clarified later, the Maneuvering Characteristics Augmentation System (MCAS) pre-Lion Air crash was not in the manual. Pilots did not know of it's existence (allegedly).

After the Lion Air crash it became a supplemental addendum, and some are arguing that was not sufficient, that additional simulator time and training should be required as the 737 Max is certainly different than the 737 that came before it, something Boeing downplayed in order to sell aircraft and obtain certifications - or so current theories hypothesize.

kach22i 03-19-2019 07:38 AM
Quote:
Both Boeing and the FAA were informed of the specifics of this story and were asked for responses 11 days ago, before the second crash of a 737 MAX last Sunday.
Oh boy.

Quote:
Since MCAS was supposed to activate only in extreme circumstances far outside the normal flight envelope, Boeing decided that 737 pilots needed no extra training on the system — and indeed that they didn’t even need to know about it. It was not mentioned in their flight manuals.

That stance allowed the new jet to earn a common “type rating” with existing 737 models, allowing airlines to minimize training of pilots moving to the MAX.
Understatement of 2019........................

Quote:
Boeing’s safety analysis of the system assumed that “the pilots would recognize what was happening as a runaway and cut off the switches,” said the engineer. “The assumptions in here are incorrect. The human factors were not properly evaluated.”

flipper35 03-19-2019 07:38 AM
The trouble i have with that article is they state the MCAS only "activates" in extreme flight conditions. The anti-stall portion of MCAS activates then, but the system is always active to make the MAX feel the same in terms of flight characteristics of the earlier models like the NG. Otherwise it is a good article.

The MCAS was designed to allow pilots to fly the MAX without additional training by making the plane appear to behave like the older ones even though there were significant changes. The system was in the manual but I doubt many felt the need to mention the system since it was supposed to be unnoticed in the background as far as the pilots were concerned. After Lion air, there should not have been a pilot on the planet that was unaware of it, the characteristics of it and how to disable it.

The AoA issue as stated by an engineer on another forum after the Lion Air says that the system takes an out of proper parameters of one sensor and ignores the other, regardless of which sensor show the high AoA. It does not compare the two or vote or compare the readings to corroborate the possibly erroneous reading. Like having one kid tell you the house is on fire and the other kid says not. It automatically believes the kid that says the house is on fire, even if there is no other evidence. I am not sure this is exactly how it works, but i have seen it from a couple different ones.

beepbeep 03-19-2019 07:50 AM
Quote:
Originally Posted by flipper35 (Post 10396364)

The AoA issue as stated by an engineer on another forum after the Lion Air says that the system takes an out of proper parameters of one sensor and ignores the other, regardless of which sensor show the high AoA. It does not compare the two or vote or compare the readings to corroborate the possibly erroneous reading. Like having one kid tell you the house is on fire and the other kid says not. It automatically believes the kid that says the house is on fire, even if there is no other evidence. I am not sure this is exactly how it works, but i have seen it from a couple different ones.

From my reading on PPrune, it seems that MCAS basically alternates between single AoA sensors for each flight. No vote, no comparison...just picks 1,0,1,0,1,0 etc.

This is very puzzling decision, considering the harm that non-working MCAS can cause. How on earth did FAA really certified this as safe?? A bird hits wrong AoA sensor and weeee....10 seconds of pitch down you must fight with...repeatedly...

A350 where multiple sensors are sampled and voted by FBW logic for confidence looks like hedgehog:
http://forums.pelicanparts.com/uploa...1553010466.jpg

Cited from news article above:
"The original Boeing document provided to the FAA included a description specifying a limit to how much the system could move the horizontal tail — a limit of 0.6 degrees, out of a physical maximum of just less than 5 degrees of nose-down movement."

"After the Lion Air Flight 610 crash, Boeing for the first time provided to airlines details about MCAS. Boeing’s bulletin to the airlines stated that the limit of MCAS’s command was 2.5 degrees."

Oh boy...

kach22i 03-19-2019 07:53 AM
Quote:
Originally Posted by flipper35 (Post 10396364)
The trouble i have with that article is they state the MCAS only "activates" in extreme flight conditions. The anti-stall portion of MCAS activates then, but the system is always active to make the MAX feel the same in terms of flight characteristics of the earlier models like the NG. Otherwise it is a good article.
Thank you for the clarification, and it's an important one.

widebody911 03-19-2019 07:54 AM
How on earth did FAA really certified this as safe??

Apparently they didn't - Boeing did and the FAA rubberstamped it

flipper35 03-19-2019 07:59 AM
Also, the MCAS is only in effect when the aircraft is hand flown. Its sole purpose is for the pilot to think it flies the same as the older birds. As in so they don't have to be type rated in a different block aircraft.

Beepbeep, that could be, he may have no been clear in that it takes the high aoa warning from either sensor.

sammyg2 03-19-2019 08:05 AM
More info on the A330 control malfunction i mentioned earlier where the 'puter decided that the altitude was actually an AOA reading and dropped rapidly (10 degrees, almost 700 feet instantly).
Happened to three A330s, they never figured out why.
I'm sure it'll never happen again. I can't wait until computers are driving all the cars on the freeway

<iframe width="964" height="542" src="https://www.youtube.com/embed/8AwPg6jbYMg" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

<iframe width="964" height="542" src="https://www.youtube.com/embed/MfIwh6LTQdg" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

PetrolBlueSC 03-19-2019 08:27 AM
I predict that Boeing and Airbus will never allow their planes to be flown without pilots. If there is no pilot, who would they blame for design and training failures?

beepbeep 03-19-2019 08:42 AM
Quote:
Originally Posted by widebody911 (Post 10396394)
How on earth did FAA really certified this as safe??

Apparently they didn't - Boeing did and the FAA rubberstamped it
This is fcuked up on so many levels. Boeing gives FAA wrong info ("it's only 0.5 degrees, I swear"), on which FAA says "oh, go ahead and certify it yourself". So they do...except they tweaked it to 2.5 degrees as 0.5 didn't work...

javadog 03-19-2019 09:35 AM
From the article linked above:

"On the Lion Air flight, when the MCAS pushed the jet’s nose down, the captain pulled it back up, using thumb switches on the control column. Still operating under the false angle-of-attack reading, MCAS kicked in each time to swivel the horizontal tail and push the nose down again.

The black box data released in the preliminary investigation report shows that after this cycle repeated 21 times, the plane’s captain ceded control to the first officer. As MCAS pushed the nose down two or three times more, the first officer responded with only two short flicks of the thumb switches.

At a limit of 2.5 degrees, two cycles of MCAS without correction would have been enough to reach the maximum nose-down effect.

In the final seconds, the black box data shows the captain resumed control and pulled back up with high force. But it was too late. The plane dived into the sea at more than 500 miles per hour."

After correcting the problem 21 times, why did it not occur to the captain to turn off the damn stabilizer trim switches? I'd wager that he should have realized he had a problem with the stabilizer trimming itself without being commanded.

billybek 03-19-2019 10:02 AM
https://www.msn.com/en-ca/money/topstories/air-canada-grounds-boeing-max-8s-until-at-least-july-1/ar-BBUXV5k?ocid=spartandhp

Eric Coffey 03-19-2019 11:33 AM
Quote:
Originally Posted by javadog (Post 10395811)
I’m fairly certain that a competent pilot would recognize the fact that the stabilizer trim is being manipulated without pilot input. That is something that they do train for, it really doesn’t matter why the stabilizer is moving uncommanded. The fix is the same and it’s been that way for 50 years.
Yep, it's essentially a runaway trim issue. The procedure for dealing with such is in the manual, QRH, and is also a primary memory-item. The only real issue is that the initial action/ability to halt the auto-trim by manually pulling back on the yoke/column no longer works on an A/C with an MCAS fault. However, the follow-on procedure if the problem persists remains the same (stab. trim cut-out switches). So, any competent 737 driver should be able to deal with the problem effectively, even if they had no idea what MCAS was.
Quote:
Originally Posted by javadog (Post 10395811)
I don’t mean any disrespect to the pilots that crashed these two jets but I truly believe that that would not of happened with the frontline pilots we have here in this country.
With only 200 hours total, the FO of the last one wouldn't even be allowed in the right seat if it was a US flight.

Eric Coffey 03-19-2019 11:45 AM
Quote:
Originally Posted by javadog (Post 10396549)
After correcting the problem 21 times, why did it not occur to the captain to turn off the damn stabilizer trim switches? I'd wager that he should have realized he had a problem with the stabilizer trimming itself without being commanded.
+1

From post #82:
Quote:
Originally Posted by Eric Coffey (Post 10388175)
Not only that, but I believe it's only "active" when flying manually, and/or with flaps up, and/or with extreme pitch/bank angles. It can also be temporarily overridden via elec. trim switches on the yoke, or manual trim wheels.
Further, it would seem that the standard procedure for runaway trim is applicable to faulty MCAS, albeit a bit updated now.

I can't imagine how/why a pilot would attempt to "fight" a problem like that for any lengthy period of time before initiating runaway trim procedures, all the way to stab. trim cut-out. However, that appears to be a possibility with the Lion Air crew, and maybe even the Ethiopian flight (alt. oscillations noted). As mentioned, the previous crew on the Lion Air A/C had essentially the exact same problem. They dealt with it appropriately and continued their flight without issue.

That said, I still think the big problem is the lack of training/awareness of the new system, and the differences in the initial runaway trim procedure.
As I mentioned previously, one could halt runaway trim on the "old" 737 by simply pulling back on the column (break-away). That won't work on an MCAS equipped A/C. You have to disable the trim altogether (cut-out).
While that was always the final step in the "old" 737 runaway trim procedure, the initial step of pulling back on the yoke no longer works with a faulty MCAS system. Sort of counter-intuitive, IMO.
I think the system/procedures/manuals need a minor update to address the fact that trim break-away via control column is no longer effective.
Although, again, I can't imagine any competent 737 driver would just keep pulling back on the yoke, with no results, all the way to the ground.

daepp 03-19-2019 01:29 PM
Quote:
Originally Posted by Seahawk (Post 10392249)
The start of a flight and the terminal phase of a flight are when the aircrew is most diligent...that is when the majority of aircraft accidents happen.
http://forums.pelicanparts.com/uploa...1552673141.gif
I have no training in this area whatsoever, but I would think those stats gain even greater weight when you consider the takeoff and terminal phases are measured in minute, whereas the cruise phase is typically measured in hours.

Neilk 03-19-2019 06:48 PM
Well looks like the penultimate Lion Air flight had a savior in the form of a deadheading jumpseat pilot per Bloomberg

Quote:
That extra pilot, who was seated in the cockpit jumpseat, correctly diagnosed the problem and told the crew how to disable a malfunctioning flight-control system and save the plane, according to two people familiar with Indonesia’s investigation.
Points to bad training but also poor communication of new features by Boeing.


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