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Boeing 737 Max Recertification Testing - Finally.

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Boeing 737 Max Recertification Testing - Finally.

Old 7th Sep 2020, 21:53
  #261 (permalink)  
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Is not the issue of what happens if another Max gets into trouble? It would be totally destructive of any confidence in the regulatory apparatus.
So what is being incrementally provided to the pilots to help them cope if another Max goes wonky?:The Ethiopian guys knew all about it and they still got killed. What is going to make for a different outcome now?
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Old 7th Sep 2020, 22:10
  #262 (permalink)  
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First impression of the agreement for deferral of Synthetic Airspeed addition is that it tends to unwind some, at least, of the Gordian knot that the MAX has become, compared with the more typical processes of approvals by air safety regulators.

Still it will be very interesting to see what the other participants in this process, or should it be the various constituents of participants - have to say about this reported agreement, assuming it bears out as fact. Color me skeptical that the Dep't of Transportation Inspector General (and Office of General Counsel), both of which were pretty acerbic in their initial reports on the regulatory debacle, will find this agreement a bright spot (despite it appearing to be a case of necessity mothering invention). And what will the FSB (Flight Standards Board) and JOEB (Joint Operations Evaluation Board) have to say? - although perhaps JOEB blessed this or is known by inside players to be very likely to bless it??

I'm not reaching what the legislation-writing committees on Capitol Hill, who are ginning up various measures to address the certification process, will make of this deferral agreement. But I will say that a contact of which I am aware, which was made to the attorneys conducting the FOIA lawsuit against FAA and which offered meaningful assistance for coordinating, with other MAX litigation, the "shadow FAA" effort which the FOIA lawsuit is supposed to enable, met with studied non-response. I'm told the contact, made to attorneys at the FOIA plaintiffs' law firm who were general counsel to the national committee of one of the two major political parties, came from a person more associated with the other major party. Maybe the FOIA lawsuit has produced so little timely response by FAA (probably in large part due to Boeing assertion of proprietary privilege on many documents) that any chance for the crew assembled by the plaintiffs, which is headlined by Capt. Sully, to speak to the issues before hard decisions are taken. In any event, it also would be most interesting to know what this crew (the expert panel assembled by the FOIA lawsuit plaintiffs) think of this deferral arrangement.

Not least, one wishes a lot fewer lawyers, and a lot more aeronautical engineers -- oh, and pro pilots -- were involved in all this.

Last edited by WillowRun 6-3; 8th Sep 2020 at 13:39.
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Old 8th Sep 2020, 06:31
  #263 (permalink)  
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There are excellent GPS based AHRS units commonly used in GA that would give the required information to keep control of the aircraft while they regain situation awareness and sort out any technical issues. These units only require a power source and have a back-up battery and provide GPS ground speed (that can be switched to IAS...but why would you?), GPS track, GPS attitude, GPS bank angle and GPS vertical speed. Certainly more use than a liquid compass with a correction card or a standby horizon that requires data from faulty aircraft sensors...cost...£1500 to £2000.
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Old 8th Sep 2020, 08:35
  #264 (permalink)  
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Your links report what has been suggested, but not necessarily the current situation; neither EASAs view of the proposed modifications or actually how the changes will achieve the sort of redundancy required for recertification.
The core problem is the use of dual AoA sensors in a control system which requires a higher level integrity.

With new MCAS protections, a residual issue is how to minimise the number of alerts associated with an AoA Disagree; - continuous stick-shake, IAS and ALT Disagree, the new AoA Disagree, conflicting EFIS low speed awareness, Air Data, etc.
Airspeed per se is not the problem.

With an AoA failure after takeoff the crew has to prioritise activities; - approach to the stall, potential UAS, - but there is a standby ASI, but, but, the potentially useful AoA display is also unreliable, … and, … all combinations of alerts and distractions in-between.
There is potential for confusion and high workload, which in certification terms depends on how this is judged - subjective.

An interesting technical aspect of the mod is the use of the Split Vane (AoA) monitor, and 'new' Middle Value Select function - FAA Preliminary View 6.1.3. This appears to involve some novel computational techniques (assumptions ?) to differentiate between 'valid' and 'valid failed', and 'valid erroneous' AoA data. My non-technical appraisal suggests that this is similar to, but not the same as, a triple AoA input. Possibly an average of small differing values - incorrect, but good enough for some situations.

These changes could move the certification argument from unacceptable workload / consequences of a single failure - specifically MCAS, from subjective judgement - which for MCAS with hindsight was incorrect, to a certification probability / reliable argument; i.e. from qualitative to quantitative certification, where the first depends on who makes the judgement and the second on numerical appraisal.
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Old 9th Sep 2020, 00:21
  #265 (permalink)  
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It is highly probable that the original MCAS design would not have resulted in the upset accidents. It was when the MCAS power was dramatically increased that it became really dangerous. This increase in the power of MCAS was the result of the failure of the original system to allow the airplane to meet certification standards. From what I can see the new MCAS light configuration has even less effect on the flying characteristics than the original lower powered version. So if that version could not meet the certification standards then one even less powerful obviously will not. So how has Boeing and the FAA got around this conundrum ? What am I missing here ?
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Old 9th Sep 2020, 00:57
  #266 (permalink)  
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"So how has Boeing and the FAA got around this conundrum ? What am I missing here ?" (Big Pistons Forever)

It was questions exactly like these which were the premise of the FOIA lawsuit against FAA. The point of that litigation was to force FAA to divulge the documentary record upon which it was proposing to act with regard to returning the aircraft to service. And more specifically, to divulge those documents so that a group of independent, distinguished experts and authoritative professionals could inform the public about whether FAA's proposed action would meet safety requirements. The disclosures, and the review, were intended to be complete before the return to service decision would be made final.

But FOIA litigation doesn't exactly move with speed requiring wind tunnel tests.

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Old 9th Sep 2020, 14:31
  #267 (permalink)  
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Red face

Very little in the Federal government does. Nevertheless, in spite of the great need for fairness and transparency, regulator’s deliberations dealing with the details of type design are obliged to protect proprietary design information. Failure to do so can further restrict how much technical detail the manufacturer shares. Though, granted, it seems that Boeing may have been stingy in that regard, anyway.
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Old 9th Sep 2020, 15:14
  #268 (permalink)  
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On timing, the entire premise of the FOIA lawsuit was to obtain the documentary record on which it was anticipated the FAA would decide when, and under what conditions, a return to service would be authorized. So the nominal slow-motion imitation which much of the USFG conducts was, at least as I read the Complaint by the plaintiffs (and some parts of the court file to date), intended to be set aside. There are expedited proceedings in federal court and not only motions for temporary restraining orders (another example is reinstatement motions on behalf of aggrieved employees under Sec. 10(j) of the National Labor Relations Act).

As for proprietary rights of - in this instance - Boeing, it's indisputable that the FOIA exemption serves an important purpose. However . . . and this is not an argument over whether or not the exemption applies to this or that specific document. Instead, in this situation, it can be argued (and probably should be argued) that the proprietary interests of Boeing with regard to the design of the aircraft as such design is in question in the aftermath of the accidents, that those proprietary interests have been relinquished. The public interest in getting assurance that the aircraft this time around is in full conformance and compliance with the certification standards outweighs the interests served by protecting proprietary information.

It isn't the standard rejoinder to assertions of an exemption applying but this is far from a standard matter. If the independent group which is seeking to run a "second set of eyes" review and assessment of the FAA decision-making process isn't going to see everything, what is the point served by their court action? I don't ascribe cynical motives to their court action, whatsoever. Certainly between the legal counsel for plaintiffs - old and established Washington players - and the billable-hours minions of Boeing, somebody can craft a sufficient protective order.
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Old 9th Sep 2020, 15:39
  #269 (permalink)  
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Big Pistons Forever,
The proposals (§) don't suggest a reduction in MCAS trim rate. The system's ability to trim the horiz stab still uses the higher rate, but limited to one application of xx deg, thus in normal operation it should to provide sufficient aerodynamic effect to meet certification requirements.
The changes appear to involve higher system reliability - MCAS / AoA should not fail so often (how and why is in the small print), and if there is a MCAS / AoA failure, detection and inhibiting the trim output is improved so that the trim cannot offset by more than the pilot is capable of recovering from.

The stab trim runaway situation remains, as it does for pre Max 737s; detection, inhibit, and recovery still depend on pilot intervention, although there could be a small numerical argument from re-routing trim wiring.

Will a single trim application per AoA increase will be sufficient?
If the same aero effect from a single application as previous - trim rate and duration, then yes
If not, then flight test judgement and cert interpretation, but some trim would be better than none of the basic aircraft.
Then the debate would again be changed from a hard numerical system safety requirement (10^ - x) to a subjective interpretation of a requirement - slope of the trim curve in rarely encountered situations with minor stability effect which pilots can control, and for which there are certification precedents.

§ https://www.faa.gov/news/media/attac...ummary-v-1.pdf
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Old 9th Sep 2020, 23:14
  #270 (permalink)  
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@WR 6-3. I’m not arguing one way or the other for the FOIA request. I imagine that FAA deliberations include its consideration for details of the type design, which make a response to the FOIA at least difficult to sort through, and in preparation of the response, carefully consider its legal obligations regarding the protection of proprietary rights (trade secrets etc.). All of this adds a lot viscosity to the lubricating oil of government machinery and in no way implies reluctance to meet legal obligations of the FOIA act. Like it or not.
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Old 13th Sep 2020, 02:27
  #271 (permalink)  
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Regulators to examine pilot training for Boeing 737 Max jets The review will include aviation officials and pilots from the U.S., Canada, Brazil and the European Union
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Old 13th Sep 2020, 12:27
  #272 (permalink)  
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Wall Street Journal's aviation reporters Andrew Tangel and Andy Pasztor have a story on the website for Monday's edition which discusses interviews given to Congressional investigators (House of Representatives), by two senior Boeing managers, sometime in May. Given the paywall I'm not upping a link here. But the story indicates that the final report by that House Committee is expected to be released this week.

According to the article, the two managers defended the Boeing process for design decisions, overall.

In light of the earlier report by the House Committee, considering the description of the interviews in the article, the anticipated final report should be even more vehement. Here's a link to a Committee document which references its preliminary report, and through which most if not all of its output (including videos of hearings) can be accessed. https://transportation.house.gov/new...tive-findings-
As Congressional reports go, the preliminary report title had a kind of interesting ring to it: “The Boeing 737 MAX Aircraft: Costs, Consequences, and Lessons from its Design, Development, and Certification".

Although the FOIA litigation is a separate track in Washington, in an important context, it's the same track. Specifically, despite the usual machinations of FOIA litigation on the part of respondent government agencies, and also despite the need usually to process proprietary information carefully and in accord with the statutory scheme, the FAA is nearing a decision about return to service. Other CAAs also are in assessment and evaluation processes. The purpose of the litigation, as stated expressly in the Complaint filed in federal district court, was to enable an independent group of experts with authoritative experience to examine the full documentary record BEFORE a return to service would be decided upon. So usual FOIA processes should be out the window, and it is to be hoped that the forthcoming report from the House Committee will provide the necessary kickstart. (Tons of respect for the House Committee staff but no one has advocated equating those good people with the independent panel put together by the FOIA lawsuit plaintiffs.)
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Old 13th Sep 2020, 20:34
  #273 (permalink)  
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Two senior Boeing Co executives who oversaw the development of the 737 MAX defended the company’s decisions on a key cockpit system later tied to two fatal crashes, according to testimony before congressional investigators seen by Reuters.
Story Link:
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Old 14th Sep 2020, 02:28
  #274 (permalink)  
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Seattle Times

Boeing 737 MAX program leaders who approved flight control system say they didn’t know key details
Sep. 13, 2020 at 6:00 pm Updated Sep. 13, 2020 at 6:34 pm

By Dominic Gates
Seattle Times aerospace reporter

In testimony to congressional investigators probing the fatal crashes of two 737 MAX jets,Michael Teal, the chief engineer on Boeing’s 737 MAX program who signed off on the jet’s technical configuration, said he was unaware of crucial technical details of the flight control system that triggered inadvertently and caused the crashes.

And under questioning, both Teal and Keith Leverkuhn, the vice president in overall charge of the MAX development program, denied the airplane had any design flaws beyond an assumption that the pilots would have reacted differently to the triggering of the system.

These two top executives on the MAX program, accompanied by Boeing lawyers, were interviewed separately in May by investigators from the U.S. House transportation committee. Transcripts of the interviews, copies of which were obtained by The Seattle Times, are expected to be made public this week when the final report of the House investigation is due to be released.

Teal, vice president and chief project engineer during development of the MAX, said he was not aware that the errant flight control software that brought down the two jets — the Maneuvering Characteristics Augmentation System (MCAS) — was triggered by a single sensor.

He learned that only after the first crash, Lion Air flight JT610, he said, “Most likely through the press.”

He was also unaware that the system could activate repeatedly, as it did in the crash flights, relentlessly pushing down the noses of the jets each time the pilots pulled them up.

“I had no knowledge that MCAS had a repeat function in it during the development,” Teal told investigators. “The technical leaders well below my level would have gone into that level of detail.”

Likewise, only “when it showed up in the press” later, did Teal learn that a warning light that was supposed to tell pilots if two angle of attack sensors disagreed wasn’t working on most MAXs, including the two that crashed — even though Boeing engineers had discovered this glitch in August 2017, more than a year before the first accident.

And Teal, who said he “signed off on the configuration of the airplane to include the MCAS function,” couldn’t recall any discussion of the decision to remove all mention of MCAS from the pilot flight manuals.

Leverkuhn also said he knew nothing of these key details about the flawed flight control system and said there was minimal focus on MCAS at his level.

“MCAS is a revision of a software in the flight control computers,” Leverkuhn said. “It really wasn’t considered, to my understanding, new or novel.”

In the interviews, which were first reported Saturday by The Wall Street Journal, the two also addressed criticisms beyond the failure of MCAS: that Boeing chose to retain the earlier 737NG model’s flight deck and not upgrade the MAX’s pilot instruments to more modern regulatory standards; and that it mandated only minimal training for pilots transitioning to the MAX from the NG.

Both executives insisted these decisions were not driven by cost considerations.

Instead, said Leverkuhn, making the MAX and NG so similar that little training would be needed, with no time in a flight simulator, was a matter of safety.

“We knew that flight crews were going to be potentially flying an NG in the morning and then flying a MAX in the afternoon,” Leverkuhn said. “So for safety reasons, we wanted the MAX to have as close as possible to the same look and feel of the NG.”

“Knowing that the NG had a terrific safety record, terrific maintenance record, we knew that that airplane was familiar and ubiquitous throughout the world,” he added.

Teal echoed this: “To me, this is a safety conversation,” he said. “It’s not about the dollars and cents.”

Both executives insisted that the MAX design and development program followed Boeing’s regular process and that, as Teal put it, “there’s no reason to believe that those processes were flawed at that time.”

Teal repeated the line about Boeing having followed its tried and true processes so often in the interview that he conceded, “I sound like a broken record.”

Both men defended the Boeing process and insisted the only error made was the engineering assumption that the pilots would have reacted differently when MCAS began swiveling the horizontal tail and pushing down the nose of each jet.

Teal — now chief engineer on Boeing’s next new plane, the 777X — said Boeing would learn from this error for future airplane designs.

“I am not going to discuss whether or not the process is what was the cause of the accidents,” Teal said, then added in awkwardly cold phrasing: “I will acknowledge with you that we have had a learning. Unfortunately, we’ve had two learnings.”

When Leverkuhn was asked if, in light of the two crashes and the fact that the MAX has been grounded for 18 months, he would consider the MAX’s development a success, he responded: “Yes, I would.”

“I do challenge the suggestion that the development was a failure,” Leverkuhn insisted.

Dominic Gates: 206-464-2963 or [email protected]; on Twitter: @dominicgates.
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Old 14th Sep 2020, 03:57
  #275 (permalink)  
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Who did Leverkuhn report to at Boeing?
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Old 14th Sep 2020, 14:06
  #276 (permalink)  
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Both Teal and Leverkuhn said that they had never met MCAS and that it was a low-level coffee boy and worked for Boeing for only a short time.
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Old 14th Sep 2020, 16:31
  #277 (permalink)  
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Unsafe Culture? What culture?

Hard to fix what’s really wrong at Boeing (and FAA) when they really don’t think anything is wrong. Don’t wait for them to fix it.
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Old 15th Sep 2020, 00:24
  #278 (permalink)  
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Teal echoed this: “To me, this is a safety conversation,” he said. “It’s not about the dollars and cents.”
Oh, yes it was all about the dollars and cents, $1M per airframe to SouthWest.
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Old 15th Sep 2020, 06:51
  #279 (permalink)  
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Originally Posted by B744IRE View Post
There are excellent GPS based AHRS units commonly used in GA that would give the required information to keep control of the aircraft while they regain situation awareness and sort out any technical issues.
In GA you barely fly in the jetsstream with 100+ knots of wind speed...
This is just another "good weather umbrella" that will fail wenever it is really required.
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Old 15th Sep 2020, 17:56
  #280 (permalink)  
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Want to understand the term "root cause"? It's simple.
The story of the MAX will join with Deep Water Horizon as epitomes of the end result of profit outweighing safety on the scales of corporate culture. One could add Chernobyl and the Global Financial Crisis of 2008 in the mix to include the role of regulators in the causal chain.

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