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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 3rd Oct 2019, 19:08
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Originally Posted by Mr Optimistic
(pax). I can just about see why MCAS failure would be a major hazard (rather than catastrophic as it is still possible to recover and fly). However DAL -B has a max failure rate of 10^-7 per year. Is that really a credible reliability for the AOA sensor and processing?
​​​​​
Hazard criticality is determined first. Then based on that you design at the appropriate assurance level.
But DALs don't have failure rates.

And the criticality probabilities are per flight hour, not per year. And that's per flight hour of the entire fleet/type, not a single aircraft.

How the individual probabilities for parts of a system/subsystem add up depends on the relationships, determined in the FTA (fault tree).

And FWIW, in a FTA software failures have a probability of 1. There's really no way to calculate the probability of a defect in software, just as there is no defect free software (of any reasonable complexity).
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Old 3rd Oct 2019, 19:16
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Originally Posted by etudiant
Given the absence of any public progress to date, does anyone still believe the early 2020 return to service date?
What exactly do you think would be said/shown?

We have reports from the SIM tests of the MCAS changes by airline pilots.

Beyond that there's never really a timeline. Certification doesn't follow a A then B then C sort of process. While reviewing B, they can ask for more details, or go back to A for something, or add a new step that wasn't anticipated.

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Old 3rd Oct 2019, 19:34
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Originally Posted by ST Dog
What exactly do you think would be said/shown?

We have reports from the SIM tests of the MCAS changes by airline pilots.

Beyond that there's never really a timeline. Certification doesn't follow a A then B then C sort of process. While reviewing B, they can ask for more details, or go back to A for something, or add a new step that wasn't anticipated.
Well there was a "timeline" for the original certification when they built a jet around it's engines so.......
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Old 3rd Oct 2019, 19:41
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Originally Posted by etudiant
Lastly, has anyone in the regulatory bodies considered what the impact of a third, post return to flight fatal accident would be?
I'd think their necks are just as much on the line now as Boeing's managements. So they will surely be extra careful. To me, that suggests the odds are not good for the Max to ever return.
If you take that view it's unlikely that any aircraft will be certified again in the future.

Hopefully, the present interest in regulatory processes will lead to a recognition that elements in the skillset of a regulatory person such as competence and practical experience in whatever they're dealing with and the integrity to challenge poor safety assurance from operators and manufacturers, are essentials.
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Old 3rd Oct 2019, 20:30
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Originally Posted by jdawg
Well there was a "timeline" for the original certification when they built a jet around it's engines so.......
Well, you have that with Boeing's estimates. But I've never seen much of a detailed timeline for certification efforts.

You don't see things like the SRS for subsystem X on date Y, or status for any other certification artifacts.
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Old 3rd Oct 2019, 20:53
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Boeing digs deeper while aiming footnuke .


https://www.seattletimes.com/busines...ax-over-costs/


Congressional panel wants to interview whisteblower who says Boeing blocked key safety upgrades for 737 MAX over costs

Oct. 3, 2019 at 11:30 am Updated Oct. 3, 2019 at 12:17 pm

By Lewis Kamb
Seattle Times staff reporter

A Congressional panel investigating the deadly crashes of two Boeing 737 MAX jets that killed 346 people wants to interview the engineer who filed a scathing internal ethics complaint alleging that company management blocked key safety improvements during the aircraft’s development due to cost concerns.

U.S. House Transportation and Infrastructure Committee Chair Peter DeFazio, in a statement Wednesday, cited a Seattle Times report that first detailed engineer Curtis Ewbank’s allegations. He contended Boeing had failed to turn over Ewbank’s ethics complaint despite the panel’s request to the company six months ago for all such internal documents.

“These reports certainly add to my concern that production pressures may have impacted safety on the 737 MAX, which is exactly why it’s so critical we get to the bottom of this,” according to the statement from DeFazio, D-OR. “On April 1st we asked Boeing for all complaints regarding the 737 MAX and though we’ve been poring over hundreds of thousands of pages of documents and emails from Boeing and FAA, we were not aware of Mr. Ewbank’s complaint.”

The committee specifically asked Boeing for a copy of Ewbank’s complaint, and to make the engineer available for an interview.

“All of this information is critical to have as we prepare for our Committee’s October 30th hearing with Boeing’s CEO, as well as Boeing’s Chief Engineer of its Commercial Airplanes division, and the Chief Pilot for the 737,” the statement added.

Boeing did not immediately respond to a request for comment Thursday. An attorney for Ewbank, who previously declined to comment, also did not immediately respond to messages Thursday.

Ewbank’s ethics complaint, a copy of which was reviewed by The Seattle Times, was submitted on April 29, four weeks after the panel’s document request to Boeing. It cites specific proposals for 737 safety upgrades and generally criticizes the culture at Boeing, questioning whether the company’s safety priorities were compromised by business considerations during the MAX’s development.

The complaint suggests that one of the proposed systems for the MAX could have potentially prevented the fatal crashes of Lion Air Flight 610 last year, and Ethiopian Airlines Flight 302 this year.

A new anti-stall flight-control system, called Maneuvering Characteristics Augmentation System, or MCAS, that was implicated as a factor in both MAX crashes, may not have been activated by faulty sensors had a system called synthetic airspeed been included on the jet as proposed, the complaint suggested. Three of Ewbank’s former colleagues interviewed by The Seattle Times concurred.

The FBI, which is conducting a criminal investigation related to the MAX crashes, has since interviewed at least two Boeing employees about the complaint.

Ewbank filed his complaint seven weeks after the second fatal crash. By then, the FAA had ordered the airplane grounded and various investigations were launched, including probes by Congressional House and Senate panels.

Boeing is now preparing to submit software fixes to resolve the problems with MCAS, as well as address other issues to convince regulators to return the MAX to flight. The company also faces further scrutiny in the months ahead. The Department of Justice’s criminal investigation remains ongoing, foreign regulators and investigators have launched their own reviews, and the Congressional panels are preparing more hearings. Boeing CEO Dennis Muilenburg is expect to address the House transportation panel on Oct. 30.

Federal lawmakers have heavily scrutinized the Federal Aviation Administration’s regulatory role in the 737 MAX’s development, including delegation of some safety certification aspects to Boeing itself while the company pushed for approval of the airliner.

In May, a Seattle Times investigation found that Boeing engineers who were officially authorized as FAA delegates to help certify the MAX as safe and airworthy faced heavy pressure from Boeing managers to limit safety analysis and testing so the company could meet its schedule and keep down costs. The Times also reported Thursday, based on a review of documents, that Boeing convinced the FAA to relax safety standards for the MAX related to cockpit alerts that would warn pilots if something went wrong during flight.

Late last month, Boeing’s board of directors recommended a series of internal reforms, including changing oversight of the controversial FAA delegation program so that authorized representatives report to a new aviation safety organization within the company, rather than to business and program managers.
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The Times’ story about Ewbank’s complaint, followed by a report in The New York Times, quickly caught the attention of the House panel, prompting the request to interview the engineer, committee spokeswoman Kerry Arndt said Thursday.

Should Boeing make Ewing available for the interview, committee staff likely would interview him in private — just as it has conducted various other interviews concerning the MAX probe to date, Arndt said.

“A lot of work in this investigation has not been public-facing,” Arndt said. “That’s more so than usual because of the sensitive nature of the information. It’s been pretty locked down at this point.”
What was boeing thinking - er uh assumes capability not evident in corner offices
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Old 3rd Oct 2019, 21:47
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Originally Posted by Tobin
I expect, like myself, people are curious as to how the supposed last-ditch backup that is the manual trim wheel actually works in extreme load scenarios, how it interacts with the motor, and whether it's fit for purpose. That is entirely relevant to any discussion of MCAS, runaway trim, etc.

I'm not sure why you're in such a bad mood over this, but none of your links contain the answer to the question I and others have about the design (unless I've missed it) and saying "do your research" is not particularly helpful. We're tying to understand. With the depth and breadth of expertise from various contributors on these boards, it's surely not too much to make the query, and hope that someone who has the answer will reply.
I'll no doubt regret this- but via private message I did get a link or two which may help re the clutch. without further comment


https://lessonslearned.faa.gov/North...tem_pop_up.htm

It appears in:
https://www.quora.com/Why-did-the-FA...does-that-mean

END of this part of clutch discussion here by myself - suggest those who insist on pursuing go to Tech Log

Grebe
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Old 3rd Oct 2019, 22:06
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Originally Posted by Grebe
I'll no doubt regret this- but via private message I did get a link or two which may help re the clutch. without further comment


https://lessonslearned.faa.gov/North...tem_pop_up.htm

It appears in:
https://www.quora.com/Why-did-the-FA...does-that-mean

END of this part of clutch discussion here by myself - suggest those who insist on pursuing go to Tech Log

Grebe
I believe these are pre-737NG drawings, possibly from a 737 classic. To the best of my knowledge, the 737NG and MAX have only one stab trim motor that runs at multiple speeds, and not the two motors shown in the drawing. The clutch mechanism could be similar, but that is beyond my level of expertise.
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Old 3rd Oct 2019, 22:23
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Boeing was simply trying to milk the 737 for all it was worth, squeezing the last drop of profit from 50 years of grandfathering. Its only competitive advantage over the A32x family was the faux CCQ - Cross Cockpit Qualification. Airline managers faced with a new type certification for their crews for EICAS would then immediately consider the A32x family as coming in to play. If you are going have to type your crews anyway, your degree of freedom just increased.

Boeing was actually able to monetize this lack of training, capturing some of this value for itself by charging a higher price for an old airframe whose development costs had long ago amortised to zero. It extracted an economic rent - a profit beyond fair value. If crews had to be typed on, an airline manager would simply assign a lower future value to the new aircraft to take into account the additional training costs, and Boeing could not have extracted that rent.

Having flown in a mixed classic / NG fleet system with a 90 day recency requirement for each model. Quite frankly it was a nightmare for all involved, it imposed a large inefficiency onto the organisation and crew. I can actually understand why airlines such as Southwest would write a $1 million penalty into a MAX contract if additional simulator training was required. They would not want a mixed fleet from a crewing perspective.

Having said all that, Boeing pushed the system too far. The $10 billion in industry costs for an EICAS model is now a line ball breakeven, and 346 people have lost their lives. Even worse, the 737 line is now done, the MAX will be the last 737 model. Airline managers would look to any new narrow body from Boeing as a risky proposition compared to the mature A32x family given all the issues with the entry into service of the B787. In effect, Boeing has devaluled the future value of it's future narrow body model. It will have to offer a steep discount the A32x family initially to gain the confidence of airline managers.
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Old 3rd Oct 2019, 22:33
  #2870 (permalink)  
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Originally Posted by Tomaski
I believe these are pre-737NG drawings, possibly from a 737 classic. To the best of my knowledge, the 737NG and MAX have only one stab trim motor that runs at multiple speeds, and not the two motors shown in the drawing. The clutch mechanism could be similar, but that is beyond my level of expertise.
Yes, from postings of the same drawing in other places, it appears that these are for the Classic.
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Old 3rd Oct 2019, 22:41
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Originally Posted by Tomaski
I believe these are pre-737NG drawings, possibly from a 737 classic. To the best of my knowledge, the 737NG and MAX have only one stab trim motor that runs at multiple speeds, and not the two motors shown in the drawing. The clutch mechanism could be similar, but that is beyond my level of expertise.
You are correct sir. On the NG - One motor, and two circuits. One for main electric trim and the other for the autopilot trim.

The glaring difference between the operation of the MAX Stab Trim Cutout and the NG was discussed previously. I think ?
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Old 4th Oct 2019, 00:02
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Did this guy really say this?

Still, former FAA Certification and Regulatory Enforcement Support specialist, Larry Williams, has said any experienced pilot should have been able to handle the Max emergencies.

“You grab the yoke and pull it back and if you can’t override it you just kick off trim and fly it manually. It’s autopilot disconnect, basically. Push a button on the yoke and disconnect — grab the wheel, keep it from turning.”
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Old 4th Oct 2019, 01:09
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Originally Posted by Grebe
Nope- Kellogs has a APB out they are missing this flake ...
No Loose Rivets was correct. FAA need to look up the meaning of specialist.

https://www.scoopnest.com/user/danny...-about-reality
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Old 4th Oct 2019, 02:13
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Originally Posted by Bend alot
Did this guy really say this?

Still, former FAA Certification and Regulatory Enforcement Support specialist, Larry Williams, has said any experienced pilot should have been able to handle the Max emergencies.

“You grab the yoke and pull it back and if you can’t override it you just kick off trim and fly it manually. It’s autopilot disconnect, basically. Push a button on the yoke and disconnect — grab the wheel, keep it from turning.”
Mr. Williams may have been posting here, under multiple user IDs.
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Old 4th Oct 2019, 03:19
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SRM

Originally Posted by Grebe
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES

Boeing 737 Series Aeroplanes

AD/B737/88

Applicability: Requirement:

Compliance:

Background:

Horizontal Stabiliser Trim Electric Actuator 8/95

Model 737-300, -400 and -500 series aircraft identified in Boeing Alert Service Bulletin 737-27A1191 Revision 1 dated 3 November 1994.

Replace horizontal stabilizer trim electric actuator Part Number (P/N) 10-62033-3 with an actuator that has been modified and re-identified as P/N 10-62033-4, in accordance with Boeing Alert Service Bulletin 737-27A1191 Revision 1 dated
3 November 1994.

Note: FAA AD 95-10-05 Amdt 39-9222 refers.

Prior to 12 June 1996, except that actuators P/N 10-62033-3 may not be installed in an aircraft after 12 December 1995.

Note: Actuator P/N 10-62033-3, if installed in an aircraft prior to 12 December 1995, may remain fitted in that aircraft until removed in accordance with Requirement 1.

Several operators have reported instances where the stabilizer trim wheel continued to turn when the stabilizer trim switches were operated and released. A binding condition of a clutch disc in the stabilizer trim electric actuator was found to be the cause of the reported incidents. Action specified by this Directive is intended to prevent reduced controllability of the airplane caused by the binding clutch.
The 727 had the same problem, I had this happen to me on final approach into Brisbane many years ago.

After carrying out the Runaway Stab recall items, the trim wheels continued to rotate.

The Capt called Mayday and we obviously landed safely.

This was apparently the first time it had occurred on the 727.



Last edited by SRM; 4th Oct 2019 at 03:22. Reason: Mistake
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Old 4th Oct 2019, 04:42
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Originally Posted by ST Dog

We have reports from the SIM tests of the MCAS changes by airline pilots.
Any details on these sim tests?
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Old 4th Oct 2019, 04:55
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Originally Posted by OldnGrounded
Mr. Williams may have been posting here, under multiple user IDs.

An incredibly impressive resume as a bureaucrat. And qualified as ‘certified weather observer’ to boot !

I missed the lack of any record of ever having flown a jet in any professional capacity. However; he taught and administrated extensively. I continue to be puzzled by the fact that we ended up in this position .....





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Old 4th Oct 2019, 07:34
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Originally Posted by Bend alot
Did this guy really say this?

Still, former FAA Certification and Regulatory Enforcement Support specialist, Larry Williams, has said any experienced pilot should have been able to handle the Max emergencies.

“You grab the yoke and pull it back and if you can’t override it you just kick off trim and fly it manually. It’s autopilot disconnect, basically. Push a button on the yoke and disconnect — grab the wheel, keep it from turning.”
A lot of mistakes in there. If AP is on MCAS doesn’t operate anyway. Complete confusion as to the controls required to disable trim. Also the words “you just...” smack of some other machos posting on here.
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Old 4th Oct 2019, 07:50
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Originally Posted by jack11111
Before you blame the human and think, "I would do much better", watch this video please.
Most of us know about Three Mile Island, Unit 2. Here's the story behind the story.

https://www.youtube.com/watch?v=1xQeXOz0Ncs
What a very enlightening video. We can all learn from this in so many ways. Interesting when applied to these types of threads too. I am sure it will cause many to reflect.
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Old 4th Oct 2019, 10:02
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Still, former FAA Certification and Regulatory Enforcement Support specialist, Larry Williams, has said any experienced pilot should have been able to handle the Max emergencies.

“You grab the yoke and pull it back and if you can’t override it you just kick off trim and fly it manually. It’s autopilot disconnect, basically. Push a button on the yoke and disconnect — grab the wheel, keep it from turning.”
Read that and thisFAA inspectors weren't qualified to certify Boeing 737 Max pilots, investigation finds

A government watchdog agency says some Federal Aviation Administration safety inspectors were not fully qualified to certify pilots to fly a variety of aircraft, including the troubled Boeing 737 Max.

The U.S Office of Special Counsel, acting on a whistleblower complaint, says it found instances of inspectors who had not received all required formal training and were not certified flight instructors. Yet, according to the whistleblower, the inspectors were involved in hundreds of evaluations, known as "check rides," to certify pilots to fly aircraft ranging from the Gulfstream VII to the 737 Max. The Office of Special Counsel outlined its findings Tuesday in letters to President Donald Trump and to Congress.

On the MAX, it was reported that as of yesterday, the software fix has not been submitted.
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