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MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

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MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures

Old 7th Dec 2019, 02:23
  #4301 (permalink)  
 
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Originally Posted by Bend alot View Post
Any evidence for that bird strike ET had?

Bad part was certainly a contributing factor and Neanderthal type work is not limited to African countries.

While the engineering concept of the MAX is very poor, the intentional secrecy of MCAS and the changes that had to be made for the system to work was a larger part of "everything".

If the system was known, key information given (pulling back on the stick no longer his the cut out switches guys), correct training given - we probably would not be talking about the MAX now. But it was too important for the MAX to be just an NG.

Are Boeing still doing lots of flight testing in the MAX?
All of that information was made available to Ethiopian Airlines prior to the crash and the Ethiopian pilots, the management, and Ethiopia's CAA all knew what training the pilots had. Since the plane was developed according to the requests of the customer base, the responability for it to be similar to the NG lies with those spending the money to buy them.

Blaming a single hole for the entire mess ignores the potential for another similar problem leading to similar results. Fix all the holes.
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Old 7th Dec 2019, 02:30
  #4302 (permalink)  
 
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Originally Posted by Bend alot View Post
Any evidence for that bird strike ET had?


Are Boeing still doing lots of flight testing in the MAX?
No test flights for BOE 1 since Saturday November 23 as per flightaware.com. So that's two weeks without any further aerial work. So that means either Boeing feels it has adequately tested the MAX to an extent that should satisfy regulators or that it hasn't got satisfactory answers as of yet, literally acknowledges it needs to go back to the drawing board.

I favor the first possibility.
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Old 7th Dec 2019, 02:47
  #4303 (permalink)  
 
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Boeing Fined $4 Million for knowingly installing faulty parts

Safety regulators want to fine Boeing nearly $4 million, saying that the company installed critical wing parts on 133 planes even though it knew the parts were faulty.

The Federal Aviation Administration announced the proposed civil penalty on Friday.

The FAA action covers parts on Boeing 737s known as slat tracks, which sit at the front edge of a plane's wings and guide the movement of panels called slats. The slats help give planes more lift during takeoffs and landings. The FAA said the tracks were made brittle during a process in which they received a coating of cadmium and titanium, and that suppliers notified Boeing of the problem. Boeing still submitted the planes for FAA flight approval even after deciding that the slat tracks “could not be used due to a failed strength test,” according to an FAA statement.
There must be more to this story, maybe it was covered elsewhere? Was the plan to certify the planes and fix them before delivery? That would be shockingly lax, but not as shocking as delivering planes with such a major known defect.

By the way, for reference "Muilenburg’s compensation last year was worth $23.4 million, including a $13.1 million bonus and $7.3 million in stock awards. Stock awards from previous years that vested in 2018 pushed Muilenburg’s haul to just over $30 million."
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Old 7th Dec 2019, 04:20
  #4304 (permalink)  
 
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Originally Posted by MechEngr View Post
All of that information was made available to Ethiopian Airlines prior to the crash and the Ethiopian pilots, the management, and Ethiopia's CAA all knew what training the pilots had. Since the plane was developed according to the requests of the customer base, the responability for it to be similar to the NG lies with those spending the money to buy them.

Blaming a single hole for the entire mess ignores the potential for another similar problem leading to similar results. Fix all the holes.
Can you please direct me to the information made available that states that pulling back on the control column no longer activates the electric trim switches (as it does in every other B737 model) located at the base of the column.

I recall a vague explanation of MCAS and a waffle of an AD that casually said carry out a run away trim if some of these things happens under some of these condition, oh and you might want to use the manual electric trim to get into trim first before hitting the cut out switches.

It is pretty clear Boeing and the FAA were trying thier best to play down the MCAS MAX issues after the first crash, even after the second. Recently it seems the FAA have woken up, but Boeing are still very much in denial of the problems leading up to MCAS and post 2 fatal crashes.

It seems nothing has changed at Boeing.
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Old 7th Dec 2019, 04:49
  #4305 (permalink)  
 
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Originally Posted by Water pilot View Post
Boeing Fined $4 Million for knowingly installing faulty parts


There must be more to this story, maybe it was covered elsewhere? Was the plan to certify the planes and fix them before delivery? That would be shockingly lax, but not as shocking as delivering planes with such a major known defect.

By the way, for reference "Muilenburg’s compensation last year was worth $23.4 million, including a $13.1 million bonus and $7.3 million in stock awards. Stock awards from previous years that vested in 2018 pushed Muilenburg’s haul to just over $30 million."

Say what ?? Cadmium and titanium in contact is a major no no - As far back as mid 1960's the embrittlement of titanium parts in contact with cadmium has been well studied and known.

Titanium is embrittled by cadmium from room temperature (solid Cd) up to the 320 C (molten Cd). This includes alloys such as Ti-6Al-4V, Ti-13V-11Cr-3Al, and Ti-8Al-1Mo-1V, not just CP Ti. The Cd must be smeared or pressed into highly stressed Ti surface such that the passive TiO2 film is compromised. References include the following:

"Stress Corrosion Cracking of Titanium Alloys" by R.W. Schutz, pages 265-297 in Stress Corrosion Cracking edited by R.H. Jones (ASM International, 1992)

"Solid Cadmium Embrittlement: Titanium Alloys", p 409 in Corrosion vol 236, no. 10, Oct 1970 by D.N. Fager and W.F. Spurr

"Solid Cadmium Cracking of Titanium Alloys", p 192 in Corrosion vol 20, no. 5, May 1973 by D.A. Meyn
A bit more - During the 2707 ( SST) program at Boeing in the 60's- and as a result of certain testing and information from other aerospace companies and military programs, the embrittlement issue was well known. So much so that all shop tools- wrenches, etc ( which are commonly cad plated ) were verboten. So boeing paid for personal tools to be stripped and nickel plated. Of course the embrittlement problem was worse at expected skin temperatures at supersonic speeds, and or also where moisture is present.

Corrosion Control

Lee H. ErbOriginally published September 1997

(Whether you’re building an SR-71 or a homebuilt with a titanium gear spring, this will be important...)DON’T MIX TITANIUM AND CADMIUM

A cadmium plated bolt installed in a titanium part will eventually result in titanium "embrittlement." Just recently I found out the mechanism for titanium embrittlement: The cadmium, under pressure and/or heat, will flow (infuse) between the grains of titanium. This weakens the grain boundaries and when the titanium is stressed, a crack will initiate.Use passivated stainless steel bolts in the AN and NAS series when bolting a titanium part. Examples are AN4C10 and NAS6304U-10. AN4C10 is a 1/4-inch diameter bolt, 1-5/64 (nominally 1 inch) long, 7/16-inch grip, made of a corrosion resistant steel in the 90 ksi tensile range. NAS6304U-10 is a 1/4-inch diameter bolt, ??? long, 10/16 grip, made of A286 corrosion resistant steel and unplated.

Note: The NAS63xx series is A286 cres (cres--corrosion resistant steel, i.e. stainless steel) in the 160 ksi tensile range. The NAS62xx series is alloy steel and the NAS64xx series is 6AL-4V titanium in 160 ksi tensile range at normal temperatures. At 450 deg F it is good for 95 ksi. (Bolt selection is another long subject.)

Even the preparers of the NAS specifications had to learn about titanium embrittlement. When the spec was initially prepared in 1968 there was a cadmium plated titanium bolt defined. The galvanic table indicates that it would act sacrifically as on a steel bolt. It was declared "Inactive for New Design" after December 1991.

Thanks again to Steve Mitchell and Ron Yarborough for sharing their knowledge.
https://corrosionjournal.org/doi/abs...9312-26.10.409

So what magic system is Boeing using to prevent such embrittlement ??




https://ntrs.nasa.gov/archive/nasa/c...9950025352.pdf

https://en.wikipedia.org/wiki/Metal-..._embrittlement


https://www.faa.gov/documentLibrary/...r/AC_43-4B.pdf

32.5 Titanium. Titanium is prone to cause severe corrosion of adjacent parts through galvanic corrosion. Titanium parts may be galvanically isolated from adjacent parts through barrier coatings or films. Frequent inspection for degradation of these barrier films and inspection for corrosion of adjacent parts is recommended. Contact with zinc and cadmium-plated parts can promote cracking of the titanium.

Last edited by Grebe; 7th Dec 2019 at 05:36. Reason: add a few more document links
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Old 7th Dec 2019, 05:51
  #4306 (permalink)  
 
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Worth reading as to FAA and MMEL list re 737 MAX and ??

https://leehamnews.com/2019/12/06/fa...on-of-the-max/

December 6, 2019, ©. Leeham News: The FAA issued a draft of the updated Master Minimum Equipment List (MMEL) for the Boeing 737 MAX 8 and 9 on its website yesterday. It’s there to be commented on by anyone who has input to its content within 30 days.
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Old 7th Dec 2019, 11:49
  #4307 (permalink)  
 
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If MCAS related items are a no go item on a MMEL, are they also a land at nearest port in flight?

It is either very serious or it is not FAA and other regulators!

But lets sneak a few things past over the festive season is my impression .

Pilot unions should demand raw air-frame flight characteristics within the entire normal flight envelope.

Why that has not been released is just, well telling.
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Old 7th Dec 2019, 13:37
  #4308 (permalink)  
 
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Originally Posted by Bend alot View Post

Pilot unions should demand raw air-frame flight characteristics within the entire normal flight envelope.
When will Boeing accept that putting new engines on an old airframe not designed to carry them was a mistake?

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Old 7th Dec 2019, 13:59
  #4309 (permalink)  
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Originally Posted by Bend alot View Post
Can you please direct me to the information made available that states that pulling back on the control column no longer activates the electric trim switches (as it does in every other B737 model) located at the base of the column.
Just to emphasize, in case anyone isn't sure (I know you are, Bend), the answer to that question is, "No, because that information was not made available prior to the ET crash."

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Old 7th Dec 2019, 14:12
  #4310 (permalink)  
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Originally Posted by Bend alot View Post
If MCAS related items are a no go item on a MMEL, are they also a land at nearest port in flight?

It is either very serious or it is not FAA and other regulators!

But lets sneak a few things past over the festive season is my impression .

Pilot unions should demand raw air-frame flight characteristics within the entire normal flight envelope.

Why that has not been released is just, well telling.
It's getting harder than ever to accept the assertion that MCAS is intended only to address the issue of stick force gradient. And it was already pretty difficult to swallow that.

If pax and the general public understood this, the whole world would be demanding the results of bare airframe tests.
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Old 7th Dec 2019, 14:22
  #4311 (permalink)  
 
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Originally Posted by Grebe View Post
Worth reading as to FAA and MMEL list re 737 MAX and ??

https://leehamnews.com/2019/12/06/fa...on-of-the-max/
Draft MMEL to be found here: https://www.faa.gov/aircraft/draft_d...ft_Round-2.pdf

Have commented about premature announcements and SEC relevance before. Don‘t think it will become relevant now. The chessboard is arranged. The return is imminent. US pension fonds and institutional investors are safe.
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Old 7th Dec 2019, 14:57
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Originally Posted by BDAttitude View Post

Draft MMEL to be found here: https://www.faa.gov/aircraft/draft_d...ft_Round-2.pdf

Have commented about premature announcements and SEC relevance before. Don‘t think it will become relevant now. The chessboard is arranged. The return is imminent. US pension fonds and institutional investors are safe.
Depending on browser, one can use ( Safari for example )-after bringing up document, type command f ( same time ) and small search window opens and when you input a word lIke battery- a few seconds later, the number of matches will show up and you can use < or > to cycle thru each occurance.

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Old 7th Dec 2019, 17:33
  #4313 (permalink)  
 
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Originally Posted by BDAttitude View Post
Have commented about premature announcements and SEC relevance before. Don‘t think it will become relevant now. The chessboard is arranged. The return is imminent. US pension fonds and institutional investors are safe.
This sounds just like Boeing's "within 3 months from today" pronouncements, which have been a recurring item since last Spring.
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Old 7th Dec 2019, 17:46
  #4314 (permalink)  
 
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Originally Posted by Sallyann1234 View Post
When will Boeing accept that putting new engines on an old airframe not designed to carry them was a mistake?
Don't hold your breath.
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Old 7th Dec 2019, 18:34
  #4315 (permalink)  
 
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RTS plans are well advanced with many airlines that currently have grounded MAX aircraft in their fleets, these aircraft have not been mothballed but rather are in constant maintenance. My understanding is that Boeing will in effect will re deliver all grounded MAX aircraft as new in respect of warranties, this clearly can't happen overnight.

With regard to pilot training I'm unconvinced that there is an actual need for further simulator training given that for the last 18 months crews have been exposed to endless trim runways on CL & NG sims and the outcome hasn't always been successful in my observations, the prime cause being unable to quickly decide whether what they are seeing is normal STS behaviour ( including auto land pre trim nose up for a possible go around) the one comment I like from above posts is a MCAS warning light, similar to the STAB OUT OF TRIM light, crude but simple.

Having said all of the above it is unthinkable that Boeing and or operators could put the aircraft back in to service without further sim training, for to do so it would only take a matter of days before someone passed this onto the press who would have a field day.

There are more sims available now and I understand its easy enough to stick a software patch on an NG to mimic MCAS which is only software after all, talk of a minimum hours to fly the max compared to the NG is rubbish, there is very little difference in the handling of a MAX v NG (MAX is easier to fly in my experience)

How you get the public on board with the MAX will be interesting, airshows, discounted ticket prices, but the fuel burn is so much lower even Greta ought to get onboard

2020 will be an interesting year.
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Old 7th Dec 2019, 19:28
  #4316 (permalink)  
 
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Originally Posted by Bend alot View Post
Can you please direct me to the information made available that states that pulling back on the control column no longer activates the electric trim switches (as it does in every other B737 model) located at the base of the column.

I recall a vague explanation of MCAS and a waffle of an AD that casually said carry out a run away trim if some of these things happens under some of these condition, oh and you might want to use the manual electric trim to get into trim first before hitting the cut out switches.

It is pretty clear Boeing and the FAA were trying thier best to play down the MCAS MAX issues after the first crash, even after the second. Recently it seems the FAA have woken up, but Boeing are still very much in denial of the problems leading up to MCAS and post 2 fatal crashes.

It seems nothing has changed at Boeing.
The trim cutout switches in the control column are a red herring. The Lion Air preliminary report gave the exact steps that were taken to save the plane and the exact steps that crashed the same plane the next day. I also looked at the FCOM page that was sent to Ethiopian Airlines explaining the system, information posted by a pilot in Ethiopian Air employ.

In addition - depending on those column cutouts in the event of trim runaway is not a smart thing to do. Whatever causes trim runaway is unlikely to read the manual of how things are supposed to work, so if there is a short circuit or other wiring failure, those switches are useless and there had better be a plan B to use the instant plan A fails.
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Old 7th Dec 2019, 19:50
  #4317 (permalink)  
 
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Originally Posted by EIFFS View Post

...How you get the public on board with the MAX will be interesting, airshows, discounted ticket prices, but the fuel burn is so much lower even Greta ought to get onboard...
Notes from the public (this SLF), having watched from the nosebleed seats here for almost a year now:

1. Allow true 3rd party test pilots/certifying agencies to fly the bare airframe w/o MCAS, and issue full reports on handling/safety and or anything else they find.

2. Figure out how to prove a the absence of other lurking faults, known (but kept secret) or unknown.

3. Find all the 737 pilots who have publicly stated (here and in wider media) THEY would never fly a MAX, and see if they would change their minds.

Since 2 is impossible, I'm never flying in a MAX. Period.

I could be convinced that MCAS will be fixed (am not yet...), but pretty much will never be convinced that a rushed retro fit of an antique airframe is really safe. Plus, pickle forks, slat rails, Boeing is not credible when they say they put safety first.
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Old 7th Dec 2019, 20:39
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Originally Posted by MechEngr View Post
The trim cutout switches in the control column are a red herring. The Lion Air preliminary report gave the exact steps that were taken to save the plane and the exact steps that crashed the same plane the next day. I also looked at the FCOM page that was sent to Ethiopian Airlines explaining the system, information posted by a pilot in Ethiopian Air employ.

In addition - depending on those column cutouts in the event of trim runaway is not a smart thing to do. Whatever causes trim runaway is unlikely to read the manual of how things are supposed to work, so if there is a short circuit or other wiring failure, those switches are useless and there had better be a plan B to use the instant plan A fails.
From the view of this interested SLF re yoke-column cutout switch. Believe you may be missing a point. AFIK ALL NG versions for the last several decades had operable yoke cutout swiches such that if pilot pulled yoke in muscle memory reaction to a sudden or noticeable AND ( dive), pulling the yoke would stop- disconnect the stabilizer, and unless another improbable fault happened, the stabilizer would stop moving and the elevator trim switches would still work. Sort of like if your car due to a flat tire swerves to right or left, your immediate reaction ( unless on smart phone ) would be to twist wheel in opposition.

The pilots in both Lion and Ethopia were never told that the addition of MCAS ( aka HAL ) essentially bypassed that switch. And if they did NOT regain near neutral ( level ) trim before using console cutout switches which cut all power to switches and autopilot and ??, the manual trim wheel was essentially unuseable. And as I recall, one of the recordings showed that a few seconds before flight termination, both pilots were pulling back maximum forc on the yoke which IF in the NG would have stopped the stabilizer AND still left the electric trim switches operable.

Just my armchair opinion
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Old 7th Dec 2019, 21:57
  #4319 (permalink)  
 
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A report from this week's Seattle meeting:

https://davidlearmount.com/?fbclid=I...Lvn6uXj0OFxC0w
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Old 7th Dec 2019, 22:30
  #4320 (permalink)  
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Originally Posted by LowObservable View Post
A report from this week's Seattle meeting:

https://davidlearmount.com/?fbclid=I...Lvn6uXj0OFxC0w
Thanks.

From the linked report:

But why is MCAS – which is unique to the Max – required at all? Boeing insists it was not fitted as an anti-stall system, because the aircraft already has stall warnings and stick-shakers.The purpose of fitting MCAS, [test pilot and V.P. Ops] Bomben explained, was to compensate for a slight change in the low-airspeed aerodynamics of the 737 Max compared with the NG.MCAS was only designed to trigger in an unlikely (but obviously possible) combination of circumstances that can cause the aircraft’s centre of lift to move slightly further forward, altering the weight-balance equation. It only happens when the Max is at low airspeed with the flaps up, and is being flown manually. At low airspeed (200kt or thereabouts) – and flapless – the aircraft would be at a high angle of attack and close to the stall.
But . . . that describes the case for the first revised version of MCAS (rapid movement of stab up to 2.5 units), not the situation the system was initially designed to address (allegedly, stick force gradient in wind-up turns).

Maybe Mr. Bomben forgot.
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