Boeing 737-Max. Another one down.

[MrMango 671]

1 hour ago, Gottsy said:

Ah but hindsight is such a wonderful thing

To me, it's not hindsight, but learning from past mistakes. I fault Boeing from what I know, for not making clear the limits and training what action pilots should take if a malfunction is shown on the screens 

[jacko 8,814]

11 hours ago, JONPAT said:

Boeing says "Flight crews will always have the ability to override MCAS and manually control the airplane."  The pilots had it turned off, they could have flown it to a higher altitude before reengaging the MCAS.

Might be simpler to have a system that works rather than needs to be disabled. Having an aircraft full of screaming passengers likely distracted them.

[TheFiend 1,181]

19 hours ago, JONPAT said:

Boeing says "Flight crews will always have the ability to override MCAS and manually control the airplane."  The pilots had it turned off, they could have flown it to a higher altitude before reengaging the MCAS.

The pilots were following the Boeing procedure.... which means the procedure for recovery was badly written.

Why can't you just admit that Boeing screwed up badly with the MCAS implementation on the MAX? Not only was a safety critical system designed to only use one sensor, but also the recovery procedure if a fault arises was badly written.

 

[atlas2 4,329]

On 3/14/2019 at 6:44 AM, jacko said:

And this is the only iteration with the heavier engines which I believe they moved forward to stop them hitting the ground and changed the aerodynamics such that they did this software change to push the nose down?

 

[awesum4 2,333]

Atlas,

Fascinating video.  As I said earlier this is going to cost Boeing billions. 

This has also seriously damaged FAA who have been almost god-like in their ability to impose standards on aircraft manufacturers and suppliers. I worked for a company that supplied aircraft carpet, if you weren't FAA and Boeing certified you couldn't sell to any reasonably large airline. The bureaucracy was unbelievable.

[JONPAT 222]

"Why can't you just admit that Boeing screwed up badly with the MCAS implementation on the MAX?"

OK, I now concur.  The MCAS caused those planes to crash.

[js007 795]

Am I wrong, or is the primary problem simply a design defect?  The engines were placed in a way that the plane might be hard to control.  Hence the software fix and the resulting crashes.

[TheFiend 1,181]

4 hours ago, js007 said:

Am I wrong, or is the primary problem simply a design defect?  The engines were placed in a way that the plane might be hard to control.  Hence the software fix and the resulting crashes.

The main problem with the 737 is that it is basically an aircraft the was designed in the 60's. The original design utilised under-wing engines and short landing gear. Subsequent generations involving larger diameter engines required the engines being mounted ahead of the wing due to the short landing gear. On the MAX they increased the height of the nose gear slightly to fit a larger diameter engines. Boeing also added some fly-by-wire systems control systems in the MAX update. including MCAS...

The MAX was Boeing's response to the Airbus A320NEO series. Boeing had been contemplating a new clean sheet design but took the MAX option instead as it was cheaper and quicker to develop.... With grandfathering rights on the 737 it also meant the 737MAX option was quicker to certify.

 

[Bob Belzy 150]

Found this article today, not a quick read, but very readable.

https://spectrum.ieee.org/aerospace/aviation/how-the-boeing-737-max-disaster-looks-to-a-software-developer

 

[jacko 8,814]

1 hour ago, Bob Belzy said:

Found this article today, not a quick read, but very readable.

https://spectrum.ieee.org/aerospace/aviation/how-the-boeing-737-max-disaster-looks-to-a-software-developer

 

Yes, quite lengthy but things to learn.

 Indirectly, via something Boeing calls the “Elevator Feel Computer,” it pushes the pilot’s control columns (the things the pilots pull or push on to raise or lower the aircraft’s nose) downward.

MCAS denies that sovereignty. It denies the pilots the ability to respond to what’s before their own eyes.

And this paragraph is a good summary.....

So Boeing produced a dynamically unstable airframe, the 737 Max. That is big strike No. 1. Boeing then tried to mask the 737’s dynamic instability with a software system. Big strike No. 2. Finally, the software relied on systems known for their propensity to fail (angle-of-attack indicators) and did not appear to include even rudimentary provisions to cross-check the outputs of the angle-of-attack sensor against other sensors, or even the other angle-of-attack sensor. Big strike No. 3.

Thanks for posting that.

[Bob Belzy 150]

I hadn't twigged until now that not only was MCAS enforced nose trim involved, but that the stick pusher was also involved. What with alarms going off etc, I can imagine that it would have been a very confusing situation.

[MrMango 671]

I am starting to think that the max is going to go the same path of the Brit Comet.

 

Finished and all scrapped

[Bob Belzy 150]

16 minutes ago, MrMango said:

I am starting to think that the max is going to go the same path of the Brit Comet.

 

Finished and all scrapped

The Comet bounced back, although too late to restore confidence and build market share before the B707 took the lead. People have short memories; they will be climbing back on the Max soon enough. Boeing seem to be resisting any re-badging.

[MrMango 671]

48 minutes ago, Bob Belzy said:

The Comet bounced back, although too late to restore confidence and build market share before the B707 took the lead. People have short memories; they will be climbing back on the Max soon enough. Boeing seem to be resisting any re-badging.

I disagree to  a point. The Comet was a fine  ship when they fixed the wings that would fall off, but they lost so much momentum, the 707 simply made them redundant.

 

And the same thing may happen to the Max

[Bob Belzy 150]

4 hours ago, MrMango said:

I disagree to  a point. The Comet was a fine  ship when they fixed the wings that would fall off, but they lost so much momentum, the 707 simply made them redundant.

 

And the same thing may happen to the Max

Not sure what you disagree with as I wrote pretty much what you wrote, although in different words. Incidentally a technical point, the problem was not the wings, it was metal fatigue in the corners of the window cut outs that caused the fuselage to fail. Once they switched from rectangular to oval cut outs the problem went away. In military Nimrod form, the aircraft was still operating up to March 2010.

[forcebwithu 4,853]

59 minutes ago, Bob Belzy said:

Not sure what you disagree with as I wrote pretty much what you wrote, although in different words. Incidentally a technical point, the problem was not the wings, it was metal fatigue in the corners of the window cut outs that caused the fuselage to fail. Once they switched from rectangular to oval cut outs the problem went away. In military Nimrod form, the aircraft was still operating up to March 2010.

More to do with higher than anticipated levels of stress at bolt and rivet holes.

Window shape misconception[edit]

The accident report's use of the word "window" when referring to the Automatic Direction Finding (ADF) aerial cutout panel^[121] has led to a common belief that the Comet 1's accidents were the result of its having square passenger windows. In fact, Comet 1's cabin windows were very similar in shape, with similar corner radii, to those of the Boeing 377 and Douglas DC-7,^[122] both of which were pressurised aircraft. The windows in Northwest Airlines' B-377 were in fact larger and notably more rectangular^[123] than those of the Comet 1. While stresses in the area of the passenger windows were significantly higher than de Havilland had calculated, nowhere in the accident report is it claimed that the fatigue failure of the Comet fuselage occurred was a result of the shape of the passenger windows, but instead from excessively high localised stress at bolt and rivet holes, for which insufficient reinforcing (and therefore structural load distribution) existed.^{[citation needed]} The report found that it was a combination of factors, as well as incomplete contemporary knowledge of the effects of metal fatigue, that led to the production of a fuselage that was not sufficiently strong, and for which the distribution of stress was not properly understood.^{[citation needed]}

Response[edit]

In responding to the report de Havilland stated: "Now that the danger of high level fatigue in pressure cabins has been generally appreciated, de Havillands will take adequate measures to deal with this problem. To this end we propose to use thicker gauge materials in the pressure cabin area and to strengthen and redesign windows and cut outs and so lower the general stress to a level at which local stress concentrations either at rivets and bolt holes or as such may occur by reason of cracks caused accidentally during manufacture or subsequently, will not constitute a danger."^[124]

The Cohen inquiry closed on 24 November 1954, having "found that the basic design of the Comet was sound",^[111] and made no observations or recommendations regarding the shape of the windows. De Havilland nonetheless began a refit programme to strengthen the fuselage and wing structure, employing thicker gauge skin and replacing the square windows and panels with rounded versions.^[110] The fuselage escape hatch cut-outs retained their rectangular shape.^[125]

Following the Comet enquiry, aircraft were designed to 'Fail safe' or 'Safe Life' standards,^[126] however several subsequent catastrophic fatigue failures, such as Aloha 243 have occurred.^[127]

In June 1956 some more wreckage from G-ALYP was accidentally trawled up from an area about 15 miles south of where the original wreckage had been found. This wreckage was from the starboard side of the cabin just above the three front windows. Subsequent examination at Farnborough suggested that the primary failure was probably near to this area rather than at the rear automatic direction finding window on the roof of the cabin as had been previously thought. These findings were kept secret until the details were published in 2015.^[128]

https://en.wikipedia.org/wiki/De_Havilland_Comet

 

The link below has a very good analysis of the inflight breakups the Comet suffered. Also interesting is how they originally used water instead of air to conduct pressure tests. That led to underestimating the real world effect of repeated pressurization cycles on the airframe.

http://aerossurance.com/safety-management/comet-misconceptions/

[Bob Belzy 150]

Confirms that it wasn't the wings then....

 

Some historical bedtime reading on these hot nights.

19540408-2_COMT_G-ALYY.pdf

Edited April 22, 2019 by Bob Belzy

[jacko 8,814]

This 'State of Denmark' situation keeps dropping little worrying tales , reminds me of the VW emissions fixing scam, except that didn't kill people.

 

Boeing knew of 737 MAX safety system glitch year before deadly crash.

Washington (AFP) - Boeing engineers identified a fault with a pilot warning system on its 737 MAX aircraft in 2017, a year before the deadly Lion Air crash, the company said Sunday.

 

Faulty angle of attack indicator information may have played a role in both of the deadly crashes, causing the 737 MAX anti-stall system to unnecessarily activate and push the nose down toward the ground even as pilots fought to maintain altitude.

"In 2017, within several months after beginning 737 MAX deliveries, engineers at Boeing identified that the 737 MAX display system software did not correctly meet the AOA Disagree alert requirements," the aircraft manufacturer said in a statement.

"The software delivered to Boeing linked the AOA Disagree alert to the AOA indicator, which is an optional feature," it said. "Accordingly, the software activated the AOA Disagree alert only if an airline opted for the AOA indicator."

Source.

[atlas2 4,329]

Got this sent to me on what apps ages ago but didn't post........

Please delete if too graphic...........

Shit I deleted myself.....You can find it if you look on Youtube........The scene from outside is bad enough but the video from someone's phone inside a bit too much.

 

Edited May 8, 2019 by atlas2

[jacko 8,814]

3 minutes ago, atlas2 said:

Please delete if too graphic...........

Well I hope the clips are all from the same event (rather than a scaremongering compilation) in which case I have no issues with it! The reality of what happened to these innocent people needs to be seen. 

[atlas2 4,329]

Just now, jacko said:

Well I hope the clips are all from the same event (rather than a scaremongering compilation) in which case I have no issues with it! The reality of what happened to these innocent people needs to be seen. 

Honestly  Jacko have a look on youtube and decide for yourself. 

[jacko 8,814]

6 minutes ago, atlas2 said:

Honestly  Jacko have a look on youtube and decide for yourself. 

Well I obviously got to it before you deleted the link. Harrowing and I am quite sure some would object to it. 

I would not like to re-post it myself. 

[atlas2 4,329]

2 minutes ago, jacko said:

Well I obviously got to it before you deleted the link. Harrowing and I am quite sure some would object to it. 

I would not like to re-post it myself. 

Agree...Let's hope Boeing put a fix in that's 100% or they scrap the variation.

Edited May 8, 2019 by atlas2

[Bob Belzy 150]

On 5/8/2019 at 9:29 AM, atlas2 said:

Agree...Let's hope Boeing put a fix in that's 100% or they scrap the variation.

Nobody should under estimate the impact that this will have on Boeing and I don't just mean the fears of the great un-washed traveller. This is now an issue at the highest board table level. Boeing have fucked up big time and it will require significant US political resources to recover it.

[midlifecrisis 4,048]

3 hours ago, Bob Belzy said:

Nobody should under estimate the impact that this will have on Boeing and I don't just mean the fears of the great un-washed traveller. This is now an issue at the highest board table level. Boeing have fucked up big time and it will require significant US political resources to recover it.

Boeing will be OK. The main reason is that they have one major competitor for commercial passenger jets and if you cancelled a Boeing order today, it would take years to get planes from Airbus.

"With a seven-year order backlog, Boeing increased production of the popular 737 in the middle of 2018 to 52 airplanes per month."

From a Google search, "how long to build a 737 max"