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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 9th Dec 2019, 22:32
  #4361 (permalink)  
 
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Business Insider just posted an article, here are some tidbits.


CBS News reported that Boeing said it had addressed these problems with updated software and would make these changes:
1. MCAS will now rely on readings from two sensors as opposed to just one in the original system. The new software will activate only if both sensors agree that the plane's nose is too high. Boeing had announced this updated this year.
2. Pilots will be able to override the system.
3. When they do so, MCAS will not automatically reactivate, which the original system would do multiple times.

........ Boeing also told stakeholders that it had flown 1,850 hours with the software updates and spent more than 100,000 hours engineering and test-developing them, CBS News reported.....
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Old 9th Dec 2019, 23:43
  #4362 (permalink)  
 
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and now, with more searching, I'm less sure that the MAX-10 does not have MCAS.
Why wouldnt the MAX 10 not have MCAS?

Especially given the latest MCAS version we are aware of, as OG stated, the reasons MCAS is there have not changed.

Just curious, in reading the latest MCAS, it states that the electric trim can be disabled and go to manual trim wheel....has the manual trim wheel problem been fixed?

Looking at the 77X, and those engines, one has to wonder if it has MCAS on steroids.,...
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Old 9th Dec 2019, 23:54
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Originally Posted by tdracer View Post
Nice post, too bad it's almost entirely wrong.
There is something called the "Changed Product Rule" or CPR (and before you get on about the FAA, CPR has been completely harmonized with EASA).
CPR basically says that when you make a major change to an aircraft (and new engines qualify), anything that is changed has to step up to the latest regulations.
If you bother to check the MAX TCDS, you'd find precious few regulations date back to the original 737 TCDS (mainly having to do with structures).
For all the problems with the MAX, the regulations it was certified to are not one of them.
Correcto-mundo. But the CPR is part of the problem. It needs to be simplified and it needs to lead to a much less gerrymandered certification basis.
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Old 9th Dec 2019, 23:55
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As shown by multiple posts, the CFR CPR is a problem? No, abuse of the CPR is the problem...manufacturers should know better. (who wrote and lobbied for the CPR?)

The sales of the MAX were based on what, no additional training, yet the flightdeck is reorg'd,...and some controls/features are in different places..how does a pwerpoint replace memory items (from sim training) when it hits the fan?

This is a good segway to the "children of the magenta line" where the automation is the downfall.

BTW...the MAX 10 is a whopping 1.6m longer than the MAX9....(4.1m longer than the MAX8)

Last edited by turbidus; 10th Dec 2019 at 00:20.
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Old 10th Dec 2019, 01:18
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Originally Posted by turbidus View Post
As shown by multiple posts, the CFR CPR is a problem? No, abuse of the CPR is the problem...manufacturers should know better. (who wrote and lobbied for the CPR?)

The sales of the MAX were based on what, no additional training, yet the flightdeck is reorg'd,...and some controls/features are in different places..how does a pwerpoint replace memory items (from sim training) when it hits the fan?

This is a good segway to the "children of the magenta line" where the automation is the downfall.

BTW...the MAX 10 is a whopping 1.6m longer than the MAX9....(4.1m longer than the MAX8)
1.6m longer? So 3 rows?
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Old 10th Dec 2019, 01:51
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Looking at the 77X, and those engines, one has to wonder if it has MCAS on steroids.,...
You are kidding right? Do you know how FBW works?
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Old 10th Dec 2019, 02:02
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Originally Posted by OldnGrounded View Post
I haven't done the research on the MAX-10, so this is a guess: Stretching the fuselage doesn't usually change the COG in relation to the wing chord very much (because it's important not to do that if you're not designing new wings), but it might well increase the authority of the H-stab and the elevators, so . . . more info needed.
Interesting

IF we assume no significant change ( fore and aft ) of COG, then the lever arm ( distance to effective center of gravity or lift on the stabilizer becomes a bit longer. A longer lever arm ( disregarding for the moment certain possible aero effects) means that the stabilizer could have a smaller effective area to obtain the same up or down movement around the CG. If the area was the same as on the NG or MAX, then it seems likely the range of movement of the stabilizer up or down should be somewhat less than on the MAX or the NG.

Recognize that I am NOT an aero type and do not play one on TV. However I would like to feel comfortable that the real whiz bangs who have a voice and background and facts and data are allowed to make an input and not be chained by bean counters.

Somehow - I do NOT feel comfortable- As the cost of new tooling and design and testing issues appear to have been significant.

Last edited by Grebe; 10th Dec 2019 at 05:38. Reason: clarification of movement
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Old 10th Dec 2019, 05:35
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Exclamation Boeing whistleblower to testify wed 11 dec

The New York Times

Four months before the first deadly crash of Boeing’s 737 MAX, a senior manager approached an executive at the company with concerns that the plane was riddled with production problems and potentially unsafe. That manager, Ed Pierson, plans to tell his story to Congress on Wednesday.

Employees at the Renton factory where the MAX is produced were overworked, exhausted and making mistakes, Pierson said in an interview. A cascade of damaged parts, missing tools and incomplete instructions was preventing planes from being built on time. Executives were pressuring workers to complete planes despite staff shortages and a chaotic factory floor.

“Frankly right now all my internal warning bells are going off,” Pierson said in an email to the head of the 737 program in June 2018 that was reviewed by The New York Times. “And for the first time in my life, I’m sorry to say that I’m hesitant about putting my family on a Boeing airplane.”

Pierson, who is scheduled to testify at a House Transportation Committee hearing on the two 737 MAX crashes, called on Boeing to shut down the MAX production line last year. But the company kept producing planes and did not make major changes in response to his complaints. During the time when Pierson said the Renton facility was in disarray, it built the two planes that crashed and killed a total of 346 people.


Pierson did not raise concerns about the new automated system, known as MCAS, which caused pilots on both doomed flights to lose control. He focused on the potential safety hazards resulting from production problems.

Pierson retired in August 2018, partly because he was uncomfortable with the conditions in the 737 factory. After the first MAX crash in October 2018, he took his concerns to Boeing’s chief executive, Dennis A. Muilenburg, and the company’s board. Boeing lawyers, including its general counsel, spoke with Pierson about his complaints, according to Pierson and documents reviewed by The Times. But Pierson said the company did nothing in response. The MAX has been grounded since March, shortly after the second deadly crash.

Pierson believes that the production problems may have played a role in the crashes. In both accidents, MCAS was triggered when a vane installed on the plane’s fuselage malfunctioned.

“It doesn’t make sense that new airplanes are having these kinds of problems so early in their lives,” he said.

Boeing disputed the notion of any connection between the production problems and the crashes.

“The suggestion by Mr. Pierson of a link between his concerns and the recent MAX accidents is completely unfounded,” a Boeing spokesman, Gordon Johndroe, said in a statement. “None of the authorities investigating these accidents have found that production conditions in the 737 factory contributed in any way to these accidents.”

In the interview, Pierson also identified 13 instances, besides the crashes, in which newly produced MAX jets had safety incidents, including engine shutdowns and problems with hydraulics.

“Boeing is deeply committed to encouraging its employees to raise issues — particularly those that might involve safety or quality — and provides several internal avenues for employees to do so,” Johndroe said. “Mr. Pierson did the right thing by elevating his concerns.”

Pierson described a chaotic factory that was scrambling to produce the 737 MAX despite mounting problems. By early 2018, he said, Boeing had a significant backlog in its production of 737 planes. Delays became 10 times more common, he said, and fewer than 10% of planes were being produced on time.

Despite this, in June 2018 Boeing continued with its plan to increase its production rate to 52 planes per month from 47 per month.

Pierson and his lawyers declined to answer whether he was seeking whistleblower protection or filing a federal whistleblower case. He has hired a prominent whistleblower lawyer, Eric Havian, and could stand to gain monetarily if he pursued such a case.


During this time, Pierson said, a shortage of workers, including mechanics, electricians and technicians, caused the overtime rate at the factory to more than double. Workers were completing jobs out of sequence, leading to additional mistakes. And senior executives at Boeing exacerbated the problems, he added, by berating employees about delays and urging them to work faster.

“What I witnessed firsthand, the chaos and the instability in the factory, is really unsettling to me as someone who’s been around aircraft their entire life,” he said.

Pierson first expressed his concerns to the head of the 737 program, Scott Campbell, in June 2018. Campbell told Pierson that the company was focused on safety but did not acknowledge his suggestion to shut down the production line, a drastic move that would have resulted in serious delays and significant costs to the company.

When Pierson met with Campbell in July 2018, he said, he again urged Boeing to shut down the MAX line. Pierson had spent decades in the Navy before joining Boeing and said he told Campbell that he had seen the military stop exercises over less serious concerns. In response, he claims, Campbell said, “The military isn’t a profit-making organization.”
What with U.S IG hearing on FISA abuse ( FBI and DOJ screwups onTrump -Russia ) and the above hearing, likely to be buried by most of U.S news types

Will it be on CSPAN ? Dont know but worth a try

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Old 10th Dec 2019, 07:23
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Originally Posted by MechEngr View Post
1.6m longer? So 3 rows?
Two more rows than the Max 9.
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Old 10th Dec 2019, 09:32
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So, do we know if the MAX -10 has MCAS or not?

Thanks
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Old 10th Dec 2019, 13:10
  #4371 (permalink)  

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Some posters on airliners.net assumed that, due to the new undercarriage, that the MAX-10 would not need MCAS. Then the story got picked up by the media ... The following reference (in French!) confirms the presence of MCAS:
https://www.air-journal.fr/2019-11-2...x-5216417.html
Apologies for the wild goose chase.
I suppose that the original question more or less stands:
Could a taller undercarriage permit a revised pylon and changed engine position to be used to eliminate MCAS as a last best option?
This SLF thanks you for many hours of safe flying.
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Old 10th Dec 2019, 14:08
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flying the backside of the power curve in a 737?

I'm not sure if this is too off topic, and I"m not sure where in PPRuNe this might better be posted. How easily is it to inadvertently end up flying on the back side of the power curve in a 737?

It almost sounds like this happened in a 2 year old incident in Russia, if anyone is familiar with it? Or maybe even the AirDubai accident? How possible is it to end up
flying on the wrong side of the power curve in a jet?

737-500 flying low on the approach path, with A/P OFF, and AutoThrottle ON.

=======
Utair Boeing 737-500 on approach to Moscow Vnukovo.Federal air transport regulator has revealed that the aircraft was subjected to excessive pitch – up to 45° – and bank of 95° before the crew regained control.The aircraft (VQ-BJP) had been following a precision approach to runway 06 after a service from Krasnodar on 13 October.
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Old 10th Dec 2019, 14:36
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Thomson 737 going into Bournemouth had an upset similar to what you mention -

By David Learmont - Flight Intl.
On 23/09/2007
The airspeed of a Thomson Boeing 737-300 on approach to Bournemouth airport, UK, dropped to 82kt, the aircraft stalled, and the maximum pitch-up during the crew's go-around manoeuvre was 44°, according to an AAIB report. The crew recovered control of the aircraft successfully and landed safely from a second approach.
The AAIB says the main cause was that the crew allowed the airspeed to decay to 20kt below the approach reference speed of 135kt because they did not notice the auto-throttle had disconnected for an unknown reason after it had reduced the engine power to idle thrust for the early descent.

The captain eventually noticed the low speed and took control, announcing a go-around just before the stall warning stick-shaker operated. The lowest altitude reached during the recovery manoeuvre was just above 1,500ft.

The result of applying maximum power was that the engines exceeded their full power setting, causing a nose-up pitch moment that exceeded the elevator authority, although the captain had applied full nose-down pitch on the control column. The low approach speed had caused the autopilot to motor the horizontal stabiliser to a high nose-up trim setting, and the AAIB notes that aircraft's quick reference handbook does not alert crews to the fact that trim may need to be applied to aid recovery from the stall or extreme attitudes.

One of the AAIB's recommendations is that crew should be made aware of this need.

A contributory cause of the incident, according to the AAIB, is that the auto-throttle disconnect light, which is not associated with an audible alert on 737 classic models such as this one, failed to attract the crew's attention, and the agency recommends that Boeing, the US FAA and the European EASA should study whether the alert is sufficiently effective.
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Old 10th Dec 2019, 15:49
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Originally Posted by Drc40 View Post

........ Boeing also told stakeholders that it had flown 1,850 hours with the software updates and spent more than 100,000 hours engineering and test-developing them, CBS News reported.....
1,850 hours of actual wings in the air (or even Master Switch On) time during the 10 months since grounding, much less testing hours since the final software update, is a bit hard to believe and does not pass a sanity check.
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Old 10th Dec 2019, 19:04
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Originally Posted by answer=42 View Post
Some posters on airliners.net assumed that, due to the new undercarriage, that the MAX-10 would not need MCAS. Then the story got picked up by the media ... The following reference (in French!) confirms the presence of MCAS:
https://www.air-journal.fr/2019-11-2...x-5216417.html
Apologies for the wild goose chase.
I suppose that the original question more or less stands:
Could a taller undercarriage permit a revised pylon and changed engine position to be used to eliminate MCAS as a last best option?
This SLF thanks you for many hours of safe flying.
The "taller" undercarriage is a temporary extension capacity used during take-off and probably landing. It squats back to the original height at all other times, placing the engines close to the pavement just like always. The main effect doesn't seem to be from the forward placement, but from the larger diameter which presents a far larger frontal area (radius-squared). There are overlays of the NG vs MAX and the difference in engine longitudinal placement is slight.

Making that increase permanent isn't likely. The landing gear tucks into the fuselage and any increase in length changes the wing structure by placing the upper mount farther out, increasing the bending loads on the wing, especially during landing. It would also raise the fuselage, making the low-impact ground support more difficult to do; baggage handling, fueling, food delivery, and I'm sure others. Longer escape chutes might require increases to the storage areas in the fuselage. It seems like a small change, but it snowballs pretty quickly. And the airlines, the customers, don't like snowballs.

To put the engines where they would be neutral to pitch response is likely to require a substantial increase in landing gear length making for a large snowball.
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Old 10th Dec 2019, 19:48
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Originally Posted by rog747 View Post
So, do we know if the MAX -10 has MCAS or not?

Thanks
I don't think we know.
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Old 10th Dec 2019, 22:04
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Originally Posted by theFirstDave View Post
1,850 hours of actual wings in the air (or even Master Switch On) time during the 10 months since grounding, much less testing hours since the final software update, is a bit hard to believe and does not pass a sanity check.
Well, they could use more than one aircraft. They certainly have plenty of them sitting around.
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Old 11th Dec 2019, 00:00
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Originally Posted by theFirstDave View Post
1,850 hours of actual wings in the air (or even Master Switch On) time during the 10 months since grounding, much less testing hours since the final software update, is a bit hard to believe and does not pass a sanity check.
276 days since March 10 = 6.7 hours each and every day. I doubt very much they flew every day and even if they have more than one aircraft set up for testing, still a tall ask.

A good time for the FAA to step in to confirm and check some log books while at it.

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Old 11th Dec 2019, 00:18
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There hasn't been a test flight since for over 2 weeks. Last one was Saturday November 23.
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Old 11th Dec 2019, 00:27
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I do think local media would have noticed that many fights around Renton. I'm pretty sure I saw one flight test and it was quite distinctive, no way of mistaking it for a regular flight. (It is quite impressive to see a commercial airliner pretending that it is a YAK-3 at an airshow, must have been fun for the pilots!)
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