Boeing 737 Max8 Crashes

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Gaybutton
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Re: Boeing 737 Max8 Crashes

Post by Gaybutton »

I like doing things the easy way. If I am afraid to fly on a Max8, then I won't fly on a Max8. Simple enough for me . . .

fountainhall

Re: Boeing 737 Max8 Crashes

Post by fountainhall »

gera wrote:
Fri Sep 20, 2019 5:42 pm
FH: stop pretending you are an aviation expert. You are not. And it shows.
When have I ever said I am an aviation expert? Answer? Never! You, on the other hand, set yourself up as your own aviation expert when you said this -
gera wrote:
Thu Jun 20, 2019 3:28 pm
I expect certification of the plane within two to three weeks.
Well, we know that that prediction made in June is already inaccurate by many months and the aircraft is still months away from returning to passenger service - that is, if we are talking about the USA. Probably longer for some other parts of the world!

Like GB, nothing will get me to fly on a 737 Max for at least three years after it finally returns to service worldwide and remains incident free.

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Re: Boeing 737 Max8 Crashes

Post by gera »

It turns out that a320 neo of Airbus has the same "problem" as 737 max. Guess what? Nobody is planning to ground it.
https://marketrealist.com/2019/09/could ... back-pain/

fountainhall

Re: Boeing 737 Max8 Crashes

Post by fountainhall »

Wrong again! It has been known for months that there is a centre of gravity issue with the A321 Neo in certain circumstances. Two airlines - Lufthansa and BA - have decided as a result temporarily not to sell the last row of seats. In July EASA issued a directive to airlines. This only affects the longer range A321 Neo and not the A319 Neo or the A320 Neo.

Any issue with any family of airliners is clearly a matter of concern. However, as gera would know well if he had read up about the issue, there is virtually no similarity between the Boeing and Airbus issues. Airbus does not have the MCAS system. Airbus Neo aircraft have been flying commercially since January 2016 and 914 aircraft have been delivered to more than 30 airlines. To date there have been no fatal accidents involving an Airbus Neo jet. Boeing's 737 Max, it will be recalled, had several reported instances of US pilots reporting sudden nose down incidents even before the aircraft was involved in two fatal nose down total hull loss crashes.
EASA notes that the conditions triggering its AD have “never [been] encountered during operations”.
EASA also issued a directive in January 2018 for certain Neo aircraft having a particular serial number after two Indian airlines, IndiGo and GoAir, suffered recurring problems with their Neo fleet. However, these problems related specifically to the Pratt & Whitney engines and not to the aircraft. Two other Indian airlines, including Air India, chose another engine option and have not suffered similar problems. As of January this year IndiGo and GoAir had to change their Pratt & Whitney engines 59 times.

Another reason there is little similarity between the Boeing and Airbus aircraft -
As the engines sit lower on the wing their combined effect with the rest of the aircraft and its wing is not the same as the 737 MAX.
Furthermore the issue was discovered by Airbus - not by airlines or pilots - and notified to EASA.

As for the view of pilots, there is an interesting - though very short (only two pages) thread on prune.org. (By comparison the 737 Max thread has several threads and more than 100 pages).
I can't help but compare the A321neo situation to that of the B737MAX. The initial pitch instability problem was similar in both aircraft, but the two manufacturers, A and B, dealt with the problem differently. Due to Airbus' extensive experience with FBW [fly by wire] and it's related automation, their system was far superior to the Boeing MCAS, which relied on a single sensor and could not be easily/intuitively overridden by the flight crew
The issue is similar only in that it concerns software and Airbus is working on a software patch.

https://simpleflying.com/a320neo-cabin- ... ce=Bibblio
https://leehamnews.com/2019/07/19/bjorn ... -up-issue/
https://www.pprune.org/rumours-news/623 ... ing-2.html

fountainhall

Re: Boeing 737 Max8 Crashes

Post by fountainhall »

Wall Street Journal reports -

1. Canada May Delay Return of the 737 Max to March
2. Boeing still hasn’t provided all of the requested details laying out the description and safety assessments of the MAX’s redesigned flight-control system.
The FAA is urging a core group of regulators—from Canada, Australia, Brazil and New Zealand—to approve the fixes around November, which would be roughly in tandem with informal U.S. timelines. FAA leaders also are trying to persuade aviation authorities in Europe and other regions to follow by lifting their grounding orders shortly afterward, according to U.S. government and industry officials familiar with the deliberations.

But such coordination efforts are running into significant hurdles. Canadian aviation regulators have signaled to the FAA that they expect to require pilots to undergo simulator training before they can start flying the MAX, something the FAA is unlikely to mandate. It could take until March for Air Canada to phase the bulk of its MAX aircraft into regular schedules, according to a person briefed on the details, months later than projected for U.S. operators.

In Europe, regulators previously said they won’t accept the FAA’s technical verifications of fixes and intend to perform their own certification analyses, possibly adding weeks or months to the timetable.

Meanwhile, FAA officials said in recent weeks that Boeing hasn’t provided all of the requested details laying out the description and safety assessments of the MAX’s redesigned flight-control system.
https://www.wsj.com/articles/indonesia- ... 1569185664

fountainhall

Re: Boeing 737 Max8 Crashes

Post by fountainhall »

Apologies for yet another post. But The New York Times article posted earlier was taken by some as being gospel. In fact, it is filled with major errors of fact and deliberate omissions to help "whitewash" Boeing as another experienced writer has made very clear.
The New York Times Magazine just published a 14,000 words piece about the Boeing 737 MAX accidents. It is headlined:

What Really Brought Down the Boeing 737 Max?

But the piece does not really say what brought the Boeing 737 MAX down. It does not explain the basic engineering errors Boeing made. It does not explain its lack of safety analysis. It does not mention the irresponsible delegation of certification authority from the Federal Aviation Administration to Boeing. There is no mention of the corporate greed that is the root cause of those failures.

Instead the piece is full of slandering accusations against the foreign pilots of the two 737 MAX planes that crashed. It bashes the airlines and the safety authorities of Indonesia and Ethiopia. It only mildly criticizes Boeing for designing the MCAS system that brought the planes down.

The author of the piece, William Langewiesche, was a professional pilot before he turned to journalism. But there is so much slander in the text that it might as well have been written by Boeing's public relations department.

The piece is also riddled with technical mistakes.
We will pick on the most obvious ones below. The following is thus a bit technical and maybe too boring for our regular readers.

Langewiesche describes the 737 MAX trim system and its failure mode:

That’s a runaway trim. Such failures are easily countered by the pilot — first by using the control column to give opposing elevator, then by flipping a couple of switches to shut off the electrics before reverting to a perfectly capable parallel system of manual trim. But it seemed that for some reason, the Lion Air crew might not have resorted to the simple solution.

Wrong: The manual trim system does not work at all when the stabilizer is widely out of trim (i.e. after MCAS intervened) and/or if the plane is flying faster than usual. That is why the European regulator EASA sees it as a major concern and wants it fixed.

Langewiesche knows this. He later writes of one of the accidents:

The speed, meanwhile, was producing such large aerodynamic forces on the tail that the manual trim wheel lacked the mechanical power to overcome them, and the trim was essentially locked into the position where the MCAS had left it.
Is that a 'perfectly capable system'?

Of the crashed Lion Air flight 610 Langewiesche writes:

At 6:31 a.m., 11 minutes into the flight, Suneja got on the radio for the first time. He did not know their altitude, he told the controller, because all their altitude indicators were showing different values. This is unlikely and has never been explained.

Wrong. The value given by an Angle of Attack sensor is also used in calculating the speed and attitude of a plane. If one of the two AoA sensors fails the instruments on the side that with the failed AoA sensor will show different values than those on the other side of the cockpit.

Langewiesche knows this. Further down in his piece he writes:

That story actually starts three days before the accident, when the same airplane — under different flight numbers and Lion Air crews — experienced errors in airspeed and altitude indications on the captain’s (left side) flight display that weren’t properly addressed. Those indications are driven by a combination of sensors on the surface of the airplane.

Is that 'unlikely' and unexplained?

This is an unfounded claim:

Boeing believed the system to be so innocuous, even if it malfunctioned, that the company did not inform pilots of its existence or include a description of it in the airplane’s flight manuals.

Wrong. Boeing sold the new plane with the dubious claim that it handled no differently than its predecessor. It left MCAS out of the manual because it did not want to add to training requirements for the pilots which would have contradicted its marketing claim. Furthermore Boeing did not do any additional safety evaluation when it later increased the effect of the system.

Another wrong part:

A set of independent duplicate sensors drive the co-pilot’s (right side) display. A third standby system provides additional independent backup and allows for intuitive troubleshooting when any one of the three systems fails: If two indications agree and the third one does not, the odd one out is obviously the one to ignore. This sort of arrangement helps to explain why flying a Boeing is not normally an intellectual challenge. Furthermore, the airplane provides an alert when airspeed or altitude indications disagree.

There is no general third standby system on a Boeing 737. There is a set of standby instruments for altitude and airspeed. But these give uncorrected values that differ from the ones shown on the two flight control displays. Those values are calculated by two flight computers and each takes the value of only one pitot (speed) tube and one AoA sensor into account. If an AoA sensor fails the instruments on one side show wrong values. The instruments on the other side will show different but hopefully correct values. The standby instruments will show different, uncorrected values than both of the calculated ones.
I need not continue!

https://www.moonofalabama.org/2019/09/1 ... ilure.html

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Re: Boeing 737 Max8 Crashes

Post by Jun »

gera wrote:
Tue Sep 24, 2019 7:57 am
It turns out that a320 neo of Airbus has the same "problem" as 737 max. Guess what? Nobody is planning to ground it.
https://marketrealist.com/2019/09/could ... back-pain/
The reports don't show that the Airbus has the same problem.

Boeing had software to correct pitch, with one sensor, no plausibility checks for the signal and the software has caused 2 crashes. The problem is poor software logic.
To have this with one sensor and no plausibility checks is really shoddy engineering and doesn't even match up to principles applied in electronic control of automobile braking and steering systems. [An automobile VDC/ESP system is very similar in concept to the Boeing system, except the VDC system controls Yaw angle and the Boeing system controls pitch. We don't see vehicles crashing off the road due to failure of the yaw rate sensor, as all the VDC suppliers check the yaw rate signal against other sensor signals, such as wheel speed and acceleration. If it's outside the expected envelope, the system shuts down and the warning light comes on].

The report says Airbus does not have pitch correction software. So they presumably rely on the pilot to handle this, like we have had for the last century. No crashes from this for Airbus.

Are you working for the Boeing PR department ?

fountainhall

Re: Boeing 737 Max8 Crashes

Post by fountainhall »

I suppose Boeing shareholders have every reason to play up alleged faults of the pilots and the two airlines whilst at the same time whitewashing at every opportunity Boeing's actions and minimising its faults and responsibilities.

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Re: Boeing 737 Max8 Crashes

Post by Jun »

A lot of shareholders only ever say things that are positive for the share price. This might work for very small cap stocks if reaching a wide audience, but it's kind of wasted here.
I have no intention of analysing the Boeing stock as an investment, since it's a large cap listed in the largest & allegedly most efficient market in the world. So the probability of me finding overlooked value is near zero.
HOWEVER, remarkably the price is well above levels of 3 years ago, with a high PE ratio and low dividend yield. Even less reason for me to invest it.

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Re: Boeing 737 Max8 Crashes

Post by gera »

Apparently Lion Air provided false information about maintenance of crashed Boeing. Why I am not surprised?
https://www.bloomberg.com/news/articles ... nd=premium

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