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Ethiopian airliner down in Africa

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Old 15th Mar 2019, 07:37
  #1421 (permalink)  
 
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Originally Posted by GarageYears
Either it’s a different sensor, new with the MAX
Discussed in the Lion Air thread. It's the same part number on the NG and Max. I'd have been surprised if it wasn't.

Originally Posted by CONSO
And BA knows how to make a comparison for example 787
In fact Boeing knows how to make a comparison on the Max (and NG) too - if you pay the extra $$$ when you buy your 737, Boeing will add a few more lines of code to your Air Data System software that enables the "AOA DISAGREE" warning functionality. Both SWA and AAL have that on their aircraft.
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Old 15th Mar 2019, 07:52
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Originally Posted by DaveReidUK
In fact Boeing knows how to make a comparison on the Max (and NG) too - if you pay the extra $$$ when you buy your 737, Boeing will add a few more lines of code to your Air Data System software that enables the "AOA DISAGREE" warning functionality. Both SWA and AAL have that on their aircraft.
If that is the case then there is likely only one version of the code (eases management of it), but a flag set Yes or No if the fee has been paid or not.

If so, and the right code to avoid the issue was actually installed in the aircraft but deliberately switched off, lawyers for the pax, especially those from the second accident, will have a field day.

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Old 15th Mar 2019, 07:58
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Originally Posted by WHBM
If that is the case then there is likely only one version of the code (eases management of it), but a flag set Yes or No if the fee has been paid or not.

If so, and the right code to avoid the issue was actually installed in the aircraft but deliberately switched off, lawyers for the pax, especially those from the second accident, will have a field day.
Yes, that's what I meant. In the old days, we would call that a compiler directive. The same would apply to the bit of code (also a $$$ option) that adds the AoA indicator to the PFD.
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Old 15th Mar 2019, 08:02
  #1424 (permalink)  
 
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Originally Posted by CONSO
well here is a comparison plot just found in seattle times
It's probably worth pointing out that the altitude anomaly shown at 08:40:51 on the ET plot is spurious.
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Old 15th Mar 2019, 08:03
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This from Reuters. (It appears the lawyers want the claims heard outside the USA)

The crash of Boeing Co's 737 MAX 8 passenger jet in Ethiopia raises the chances that families of the 157 victims, even non-U.S. residents, will be able to sue in U.S. courts, where payouts are larger than in other countries, some legal experts said.

Sunday's crash occurred five months after the same model of the plane went down in Indonesia, an accident that prompted a string of U.S. lawsuits against Boeing by families of the 189 victims.

The company, which has its corporate headquarters in Chicago, has often convinced U.S. judges to dismiss air crash cases in favor of litigation in the country where the evidence and witnesses are, usually where the crash occurred.

That allows the company to avoid U.S. juries, which can award hefty punitive damages to accident victims for wrongful death, emotional suffering and economic hardships of surviving family.

Boeing may have a tougher time with that strategy after the Ethiopian crash, some legal experts said.

This is partly because eight U.S. citizens died and because plaintiffs could argue that liability hinges on system design and safety decisions made by Boeing executives since the Lion Air crash in Indonesia.

"Now with two crashes with a brand-new aircraft, what Boeing did in the intervening five months is more relevant, and that all happened in the United States," said Daniel Rose, a lawyer with Kreindler & Kreindler, a firm that represents air crash victims and their relatives.
Plaintiffs will also claim Boeing failed to exercise reasonable care in designing planes or failed to inform flight crews about how the planes operate, Wolk said.

Rose, the lawyer for passengers, said two accidents so close together will put the focus of any lawsuits on the Ethiopian crash on how Boeing tried to address problems with its MCAS system after the Lion Air crash.

"Were there other efforts by Boeing to essentially minimize the problem or hide the scope of the problem?" Rose asked. If lawyers can show Boeing management acted recklessly, it could clear the way for substantial punitive damages, he said.

Some lawyers who have worked on the other side of such cases are less sure about Boeing's potential liability.

Kenneth Quinn, a lawyer who represents airlines and manufacturers, said he thought Boeing had a good chance of getting both sets of U.S. cases dismissed on forum grounds.

He said the trend in U.S. courts was in Boeing's favor.

"Increasingly, attempts to litigate foreign crashes involving foreign airlines on foreign soil are being dismissed," he said.

In November, a federal judge in Washington, D.C. dismissed a case against Boeing and other defendants stemming from the disappearance of a Malaysian Airlines flight in 2014 because the presumed crash had a stronger connection to Malaysia than the United States.

In 2011, a federal judge in Los Angeles dismissed 116 wrongful death and product liability cases against Boeing over the 2008 crash of a Spanair jet on a domestic flight in Spain, where the judge determined the cases should be heard.

If the company has to defend U.S. cases, it would likely argue that claims against it are preempted because the FAA had approved the plane's design, said Justin Green, a plaintiffs lawyer.











https://mobile.reuters.com/article/a...mpression=true
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Old 15th Mar 2019, 08:34
  #1426 (permalink)  
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Originally Posted by Capt Kremin
One options suggested by the FR data is that there was no flap set for takeoff.

The data shows a 63 second ground roll followed by a rotation at 207 knots. At this point the MCAS may have simply been doing its job.

Hard to believe this would happen, but it's happened before.
Interesting and of course would throw a spanner in -

Would any 737 MAX pilot ever entertain a flap-less takeoff from Addis with a 2300m Elev? -
This was a normal early morning departure (Temp was 16c) - busy pax load (149) for a 2 hour leg to NBO
Not sure if at or near MTOW (any cargo>?)
VR at 207 kts?
puzzled....
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Old 15th Mar 2019, 08:56
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One thing is clear amongst all the scuttlebutt, the 737 MAX is a new type not an ng with a few tweaks and a slightly different cockpit layout.
Buying a new aircraft type is a big undertaking for any airline and expensive getting their existing pilots certified on the type while still operational on the existing 737 fleet. This makes it more difficult for Boeing to sign up customers for big orders so they tricked customers into buying the MAX by certifying the aircraft as a variant so that current ng type rating applied with only new cockpit familiarity checks.
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Old 15th Mar 2019, 09:03
  #1428 (permalink)  
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I'm wondering why the engines seem to have been at high thrust in both accidents, this one and the Lion Air.

I'd imagine it to be a bit difficult to get to 383 knots at impact from 1000 feet agl, starting at 230kts say clean, at idle, because I imagine one of the first things one would do when the nose tipped over is reduce to idle.
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Old 15th Mar 2019, 09:08
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Good call Hunbet - looks like you were right !


Originally Posted by hunbet
“Evidence we found on the ground made it even more likely that the flight path was very close to Lion Air’s,”

I suspect they located the stab trim jackscrew and could tell it's position.

Also :“The FAA is ordering the temporary grounding of Boeing 737 MAX aircraft operated by U.S. airlines or in U.S. territory. The agency made this decision as a result of the data gathering process and new evidence collected at the site and analyzed today. This evidence, together with newly refined satellite data available to FAA this morning, led to this decision," the FAA said.

https://www.bloomberg.com/news/articles/2019-03-15/piece-found-in-crash-wreckage-said-to-show-jet-was-set-to-dive

A screw-like device found in the wreckage of the Boeing Co. 737 Max that crashed last Sunday in Ethiopia indicates the plane was configured to dive, a piece of evidence that helped convince U.S. regulators to ground the model, a person familiar with the investigation said late Thursday night.

Federal Aviation Administration chief Daniel Elwell on Wednesday cited unspecified evidence found at the crash scene as part of the justification for the agency to reverse course and temporarily halt flights of Boeing’s largest selling aircraft. Up until then, American regulators had held off as nation after nation had grounded the plane, Boeing’s best-selling jet model.

The piece of evidence was a so-called jackscrew, used to set the trim that raises and lowers the plane’s nose, according to the person, who requested anonymity to discuss the inquiry.
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Old 15th Mar 2019, 09:36
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737 MAX Software Enhancement Boeing’s Public Statement

The Boeing Company is deeply saddened by the loss of Lion Air Flight 610, which has have weighed heavily on the entire Boeing team, and we extend our heartfelt condolences and sympathies to the families and loved ones of those onboard.
Safety is a core value for everyone at Boeing and the safety of our airplanes, our customers’ passengers and their crews is always our top priority. The 737 MAX is a safe airplane that was designed, built and supported by our skilled employees who approach their work with the utmost integrity.

For the past several months and in the aftermath of Lion Air Flight 610, Boeing has been developing a flight control software enhancement for the 737 MAX, designed to make an already safe aircraft even safer. This includes updates to the Maneuvering Characteristics Augmentation System (MCAS) flight control law, pilot displays, operation manuals and crew training. The enhanced flight control law incorporates angle of attack (AOA) inputs, limits stabilizer trim commands in response to an erroneous angle of attack reading, and provides a limit to the stabilizer command in order to retain elevator authority.

Boeing has been working closely with the Federal Aviation Administration (FAA) on development, planning and certification of the software enhancement, and it will be deployed across the 737 MAX fleet in the coming weeks. The update also incorporates feedback received from our customers.

The FAA says it anticipates mandating this software enhancement with an Airworthiness Directive (AD) no later than April. We have worked with the FAA in development of this software enhancement.

It is important to note that the FAA is not mandating any further action at this time, and the required actions in AD2018-23.5 continue to be appropriate.

A pitch augmentation control law (MCAS) was implemented on the 737 MAX to improve aircraft handling characteristics and decrease pitch-up tendency at elevated angles of attack. It was put through flight testing as part of the certification process prior to the airplane entering service. MCAS does not control the airplane in normal flight; it improves the behavior of the airplane in a non-normal part of the operating envelope.

Boeing’s 737 MAX Flight Crew Operations Manual (FCOM) already outlines an existing procedure to safely handle the unlikely event of erroneous data coming from an angle of attack (AOA) sensor. The pilot will always be able to override the flight control law using electric trim or manual trim. In addition, it can be controlled through the use of the existing runaway stabilizer procedure as reinforced in the Operations Manual Bulletin (OMB) issued on Nov. 6, 2018.

Additionally, we would like to express our deepest condolences to those who lost loved ones on Ethiopian Airlines Flight 302. A Boeing technical team is at the crash site to provide technical assistance under the direction of the Ethiopia Accident Investigation Bureau and U.S. National Transportation Safety Board. It is still early in the investigation, as we seek to understand the cause of the accident.

Last edited by Cloudee; 15th Mar 2019 at 10:04.
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Old 15th Mar 2019, 09:37
  #1431 (permalink)  
 
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MCAS (Maneuvering Characteristics Augmentation System) is implemented on the 737 MAX to enhance pitch characteristics with flaps UP and at elevated angles of attack. The MCAS function commands nose down stabilizer to enhance pitch characteristics during steep turns with elevated load factors and during flaps up flight at airspeeds approaching stall.
(my emphasis) I'm reading this to mean that the intention is to "assist"(TM) during steep turns and not that a steep turn is a condition of MCAS operation.

That said, if the ATC is correct, there were issues including unusual speed/acceleration for most of the flight which would possibly have been with autopilot engaged when MCAS isn't active. The pilot requests turnback and then disappears off radar.

So, accepting it contradicts Occam's Razor and needs another cheesy hole, perhaps something else non-MCAS-related was seriously wrong, but then on turning back, MCAS nose down trim becomes the final nail in the coffin as evidenced by trim jack screw position on ground.
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Old 15th Mar 2019, 09:55
  #1432 (permalink)  
 
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Originally Posted by FlightCosting
One thing is clear amongst all the scuttlebutt, the 737 MAX is a new type not an ng with a few tweaks and a slightly different cockpit layout.
Buying a new aircraft type is a big undertaking for any airline and expensive getting their existing pilots certified on the type while still operational on the existing 737 fleet. This makes it more difficult for Boeing to sign up customers for big orders so they tricked customers into buying the MAX by certifying the aircraft as a variant so that current ng type rating applied with only new cockpit familiarity checks.
Precisely.
As year after year business schools pump out MBA graduates the only thing they conceive is cost and lowering it.
Labour unit cost is the single most controllable cost an airline has.

Manufacturers heard the drum beat a long time ago.
Regulators heard it too.

In the never ending battle of short term expense versus long term safety, the latter finishes a long way behind.

Consumers hear it too.

Our hubris as a species is incredible. We convince ourselves time and again absence of evidence is evidence of absence until again the 'unforeseen' appears again just to be re-learned as it was since long forgotten.
The normalisation of deviance.
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Old 15th Mar 2019, 09:58
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Originally Posted by WHBM
If that is the case then there is likely only one version of the code (eases management of it), but a flag set Yes or No if the fee has been paid or not.

If so, and the right code to avoid the issue was actually installed in the aircraft but deliberately switched off, lawyers for the pax, especially those from the second accident, will have a field day.
Ineed, after Lion Air I though Boeing should have made this feature available for free in all MAX airplanes. Could the ET be prevented if they had this display? Interestingly, Boeing only lost 15% at NYSE. For comparison, Volkswagen lost over 60% due to their emission scandal. But this could be, and should be big if it's due to MCAS.
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Old 15th Mar 2019, 09:59
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Originally Posted by Cloudee
For the past several months and in the aftermath of Lion Air Flight 610, Boeing has been developing a flight control software enhancement for the 737 MAX, designed to make an already safe aircraft even safer.
If "safer" means avoiding a crash every six months, I would say that "safe" for Boeing means "dangerous". If not, why would a safe aircraft be grounded ?
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Old 15th Mar 2019, 10:03
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And this time EASA may well not rely on the FAA for lifting ban or even worse re-certification if required...
D.P. Davies required modifications to the B707 before it was allowed on the British register so the above scenario is very possible, especially if the French want to give Airbus a leg up.

I'm surprised we haven't seen the ambulance chasing lawyers descending on the victims families en mass yet. Those of us who remember the Bhopal disaster involving Union Carbide in 1984 will remember the spectacle.
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Old 15th Mar 2019, 10:06
  #1436 (permalink)  

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Red face Options

Options on a new aircraft have long been offered, just as in a motor car. Some enhance safety, some convenience, some comfort. They all cost. To incorporate all options as standard would render the product unsaleable.

If the airline decides not to take-up certain safety-related options, on their own head be it. Not the manufacturer's.
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Old 15th Mar 2019, 10:09
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In summary then:

The newer engines required to optimise the MAX have a larger diameter than that allowed by the wing/ fuselage geometry. In order to fit those engines Boeing had to move them forward which changed the aerodynamic characteristics of the aircraft. That change consisted on insufficient pitch down moment when close to the stall in clean configuration. In order to meet certification criteria Boeing introduced a system that automatically moved the stabiliser to artificially induce the pitch down moment . In order to introduce this system with minimal costs existing equipment was used including a data input from a single source - the AOA probe. In order to reduce qualification costs this system was not mentioned in the MAX operation manuals.

In the Lion Air case the AOA probe was not calibrated properly, meaning the direction and magnitude where correct but the value was 20 degrees out. When the flaps where retracted the MCAS started to work as intended -based on the erroneous aoa data- by introducing bursts of down trim, those bursts got interrupted every time the pilot trimmed manually via the electric trim. At a certain point the crew started to pull hard at the yoke and the automatic stab trim cutout switch operated, with the effect that electric manual trim no longer worked, MCA trim in the other hand did continue to operate but it no longer got interrupted by manual pilot trim eventually trimming all the way nose down, a position that exceeds the authority of the elevator. At that point they only had two options left
1. Offload control column pressure to release the automatic stab trim cut-out then trim back to neutral.
2. Manually disconnect the electric stab trim via the override switches at the base of the throttle quadrant then use manual trim for the remainder of the flight.

Three crews managed the above but the fourth got overwhelmed in the Lion Air case. The Ethiopian on the face of it looks quite similar but there isn't enough data yet to even have a guess. A bit of a mess but where I tend to agree with Boeing is in which way is this any different from a classic runaway stabiliser? Ok there is more distractions going on but bottom line is if the stabiliser starts to run and you dont get on those disconnect switches soon enough you will end up in the same place.
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Old 15th Mar 2019, 10:16
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Originally Posted by RoyHudd
If the airline decides not to take-up certain safety-related options, on their own head be it. Not the manufacturer's.
Except the aircraft is required to achieve certain standards of safety and, it appears, does not achieve that standard without the option activated. Ergo the default design should have additional features and it is back with the manufacturer and their regulator to take action.
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Old 15th Mar 2019, 10:21
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Rated De said "As year after year business schools pump out MBA graduates the only thing they conceive is cost and lowering it"

Stop and think whether this is not utter nonsense.
You imagine Airbus gave the A320 a seven inches wider fuselage than the 737 to save operating cost?
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Old 15th Mar 2019, 10:26
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Originally Posted by Capt Kremin
The data shows a 63 second ground roll followed by a rotation at 207 knots. At this point the MCAS may have simply been doing its job.
The FR24 data do NOT show that.

After about 45" roll (05:38:45.798) and for 5 seconds the ground speed is stable at 182/183 kts while the vertical speed is positive, reaching 2368 ft/mn. Though the pressure altitude is not consistent with the speed and vspeed evolution, speed and vspeed indicates the aircraft is already airborne and climbing at 182 kts (about 170 kts IAS). And one minute later it has gained 1000 ft and speed (250 kts). Then only the problems begin, may be after retracting the flaps.
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