Don Hudson

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  1. Podcast: When Will the Boeing 737 MAX Fly Again? May 16, 2019 Joe Anselmo, Sean Broderick and Guy Norris | Aviation Week & Space Technology https://aviationweek.com/commercial-aviation/podcast-when-will-boeing-737-max-fly-again?utm_rid=CPEN1000001138147&utm_campaign=19738&utm_medium=email&elq2=7c605d60570f4bfb9c9d6949cd64d44c Comments: Some key observations..., MAX will be ungrounded next month by the FAA, other regulators will definitely not follow, (understandably skirted the obvious question, "Why?"), Boeing parking lots getting full even in the paint lot & Texas, lots of resources dedicated to MAX so reduced resources for the new B777X, "MMA" (is that "mid-term model adjustment? - something like that?), subject broached, and a turn from MMA to the possibiliity of a B737 replacement is broached. Discussion about design philosophy, reasons for "simplicity" of MCAS is Boeing expected pilots would use "runaway" drill if MCAS broke, (even though Boeing never told pilots or anyone else about the system and how it worked), AW&ST's Sean Broderick is asked by the moderator, "With the benefit of hindsight...What did Boeing do wrong?"; some good & fair observations from Sean, very few weasel words. Guy Norris was asked same; some weasel phrases, a lot of softening words, like the phrase, "sort of", rather than just coming out and stating something, lots of hesitation, equivocations & use of "words not wanting to offend" stuff). It's a good listen if one is into the informality of podcasts.
  2. Boeing 737 MAX Training Changes Eyed And Simulator Time Considered May 14, 2019 Sean Broderick | Aviation Week & Space Technology As Boeing moves closer to wrapping up changes to the 737 MAX aimed at getting the grounded fleet back into service, training has become the focal point. One key consideration is whether simulator sessions should be added to the existing MAX pilot-training package based on lessons learned from the two fatal 737-8 accidents. A third round of public input on FAA-led Flight Standardization Board (FSB) draft recommendations closes May 15, and the comments are expected to help shape a final set of minimum training protocols for all operators to build upon. The Air Line Pilots Association (ALPA) weighed in during the initial public-input window. While the pilots’ group may amend its recommendations, its original comments do not call for mandatory simulator training on the Maneuvering Characteristics Augmentation System (MCAS) scenarios for 737 MAX pilots before they can fly. But ALPA told the FAA that simulator sessions may be a prudent step to cover emergency procedures linked to MCAS failure scenarios, and should, at a minimum, be included in recurrent training. “ALPA believes that operators must ensure that this system is trained in some method, and this case should be examined by the FSB,” the association’s comments say. “ALPA recognizes the current differences [between the 737 Next Generation and the MAX] are limited to Level B, however, it should be examined that another level of training may be appropriate to adequately [instruct pilots on] this system.” If computer-based Level B training is deemed sufficient, ALPA insists it should be “robust” and include not only system details and failure scenarios but also “visual and audio descriptions” and reenactments of recent similar occurrences. The union further says that “pilots should receive hands-on flight training on the MCAS during their next recurrent training opportunity or qualification course” as simulators become available. ALPA’s initial training recommendations include other additions to the draft document as well—most of which emphasize MCAS-related differences between the NG and the MAX. The MCAS was needed for certification purposes to enhance MAX pitch stability with slats and flaps retracted at very light weights and full aft center-of gravity (CG), ensuring the MAX handled like the NG. The system activates when the aircraft’s speed approaches threshold angle of attack (AOA), or stickshaker stall-warning activation, for the aircraft’s configuration and flight profile. The union wants the AOA Disagree alert message and its relation to the MCAS added to items given “special emphasis” in MAX training. The MCAS is fed by AOA data and activates when the data show the aircraft’s nose as being too high for the current flight profile. ALPA wants pilots to understand the link between AOA Disagree alerts, which will now be standard on primary flight displays for all MAXs, and the MCAS’ role of automatically moving the horizontal stabilizer to compensate for an AOA approaching aerodynamic stall. The union also wants MAX pilots to understand that nose-down stabilizer trim applied by the MCAS cannot be countered by pulling back on the yoke. The MCAS is an extension of the 737 speed trim system (STS), which automatically moves the stabilizer to ensure pitch is maintained as speed increases. On the NG, stick-force inputs override runaway trim, including the STS runaways. On the MAX, stick force overrides all runaway trim conditions; the MCAS does not. Boeing designed the MCAS to operate in the background, and both the company and the original FSB that worked on the model’s 2017 certification determined that special training on the system’s operation was not necessary. The system was not covered in flight manuals and was largely unknown to pilots outside of Boeing until the October 2018 crash of Lion Air Flight 610 (JT610). Boeing and the 2017 FSB team also determined that pilots would recognize an MCAS-related failure as a stabilizer runaway—a common air transport issue that pilots are trained to handle with a memorized checklist. But in each 737-8 accident sequence, the crew did not immediately diagnose the MCAS inputs—trigged by erroneous AOA data—as stabilizer runaway. The pilots countered the MCAS with manual electric trim inputs, which reset the MCAS and caused it to activate again based on the continued stream of faulty AOA data. Had the crews not used the electric trim, the MCAS system would not have activated repeatedly and so would not have led to uncontrollable dives. Boeing’s software update removes this function so that electric trim does not reset the MCAS, removing the possibility of it firing again based on faulty data. It also will update manuals to include details on the MCAS. ALPA, which represents pilots at U.S. MAX operator United Airlines and Canada’s WestJet, also advises that pilots practice as many MCAS-failure-related emergency scenarios as necessary to demonstrate competency, its initial comments reveal. Boeing’s first detailed explanation of the MCAS followed the JT610 accident aftermath and listed nine related “indications and effects” that could result from an AOA Disagree alert and possible MCAS activation. In a statement to Aviation Week, ALPA emphasizes that its recommendations could change, depending in part on what Boeing’s final package of MCAS updates and training modules includes. “ALPA has not yet determined whether or not simulator training will be necessary to return the 737 MAX to service and will continue to review any and all additional information as it becomes available,” the association says. “Until Boeing formally submits its plan to the FAA for consideration and approval, it is impossible to fully evaluate what actions will need to be taken to ensure the aircraft’s airworthiness.” Regardless of what the final FSB standards say, some regulators and individual operators are expected to incorporate MCAS-related simulator sessions into their training. Air Canada has said it is already using its MAX simulator—the only one in airline hands in North America—to run its 420 MAX pilots through MCAS-related scenarios. Regulators in Europe and China are among those that are expected to conduct independent reviews of the MCAS upgrades and related training—evaluations that could see their banning of MAX operations extend well into late this year and the return-to-service requirements go beyond what the FAA approves. Boeing is close to finalizing the MAX changes and presenting its conclusive package to the FAA. The last major step is certification flight tests of the MCAS 12.1.1 software. Boeing and the agency are working to complete the tests before a May 23 regulators-only meeting during which the FAA will present its work on evaluating the MCAS updates and respond to inquiries. The 370-aircraft operational MAX fleet has been grounded since mid-March, a direct result of the Ethiopian Airlines Flight 302 crash on March 10. Boeing began working on the MCAS changes after the Lion Air accident.
  3. Ethiopian MAX Crash Simulator Scenario Stuns Pilots May 10, 2019 Sean Broderick | AW&ST Aviation Daily Wreckage from Ethiopian Airlines Flight 302. Jemal Countess/Getty Images WASHINGTON—A simulator session flown by a U.S.-based Boeing 737 MAX crew that mimicked a key portion of the Ethiopian Airlines Flight 302 (ET302) accident sequence suggests that the Ethiopian crew faced a near-impossible task of getting their 737 MAX 8 back under control, and underscores the importance of pilots understanding severe runaway trim recovery procedures. Details of the session, shared with Aviation Week, were flown voluntarily as part of routine, recurrent training. Its purpose: practice recovering from a scenario in which the aircraft was out of trim and wanting to descend while flying at a high rate of speed. This is what the ET302 crew faced when it toggled cutout switches to de-power the MAX’s automatic stabilizer trim motor, disabling the maneuvering characteristics augmentation system (MCAS) that was erroneously trimming the horizontal stabilizer nose-down. In such a scenario, once the trim motor is de-powered, the pilots must use the hand-operated manual trim wheels to adjust the stabilizers. But they also must to keep the aircraft from descending by pulling back on the control columns to deflect the elevator portions of the stabilizer upward. Aerodynamic forces from the nose-up elevator deflection make the entire stabilizer more difficult to move, and higher airspeed exacerbates the issue. The U.S. crew tested this by setting up a 737-Next Generation simulator at 10,000 ft., 250 kt. and 2 deg. nose up stabilizer trim. This is slightly higher altitude but otherwise similar to what the ET302 crew faced as it de-powered the trim motors 3 min. into the 6 min. flight, and about 1 min. after the first uncommanded MCAS input. Leading up to the scenario, the Ethiopian crew used column-mounted manual electric trim to counter some of the MCAS inputs, but did not get the aircraft back to level trim, as the 737 manual instructs before de-powering the stabilizer trim motor. The crew also did not reduce their unusually high speed. What the U.S. crew found was eye-opening. Keeping the aircraft level required significant aft-column pressure by the captain, and aerodynamic forces prevented the first officer from moving the trim wheel a full turn. They resorted to a little-known procedure to regain control. The crew repeatedly executed a three-step process known as the roller coaster. First, let the aircraft’s nose drop, removing elevator nose-down force. Second, crank the trim wheel, inputting nose-up stabilizer, as the aircraft descends. Third, pull back on the yokes to raise the nose and slow the descent. The excessive descent rates during the first two steps meant the crew got as low as 2,000 ft. during the recovery. The Ethiopian Ministry of Transport preliminary report on the Mar. 10 ET302 accident suggests the crew attempted to use manual trim after de-powering the stabilizer motors, but determined it “was not working,” the report said. A constant trust setting at 94% N1 meant ET302’s airspeed increased to the 737 MAX’s maximum (Vmo), 340 kt., soon after the stabilizer trim motors were cut off, and did not drop below that level for the remainder of the flight. The pilots, struggling to keep the aircraft from descending, also maintained steady to strong aft control-column inputs from the time MCAS first fired through the end of the flight. The U.S. crew’s session and a video posted recently by YouTube’s Mentour Pilot that shows a similar scenario inside a simulator suggest that the resulting forces on ET302’s stabilizer would have made it nearly impossible to move by hand. Neither the current 737 flight manual nor any MCAS-related guidance issued by Boeing in the wake of the October 2018 crash of Lion Air Flight 610 (JT610), when MCAS first came to light for most pilots, discuss the roller-coaster procedure for recovering from severe out-of-trim conditions. The 737 manual explains that “effort required to manually rotate the stabilizer trim wheels may be higher under certain flight conditions,” but does not provide details. The pilot who shared the scenario said he learned the roller coaster procedure from excerpts of a 737-200 manual posted in an online pilot forum in the wake of the MAX accidents. It is not taught at his airline. Boeing’s assumption was that erroneous stabilizer nose-down inputs by MCAS, such as those experienced by both the JT610 and ET302 crews, would be diagnosed as runaway stabilizer. The checklist to counter runaway stabilizer includes using the cutout switches to de-power the stabilizer trim motor. The ET302 crew followed this, but not until the aircraft was severely out of trim following the MCAS inputs triggered by faulty angle-of-attack (AOA) data that told the system the aircraft’s nose was too high. Unable to move the stabilizer manually, the ET302 crew moved the cutout switches to power the stabilizer trim motors—something the runaway stabilizer checklist states should not be done. While this enabled their column-mounted electric trim input switches, it also re-activated MCAS, which again received the faulty AOA data and trimmed the stabilizer nose down, leading to a fatal dive. The simulator session underscored the importance of reacting quickly to uncommanded stabilizer movements and avoiding a severe out-of-trim condition, one of the pilots involved said. “I don’t think the situation would be survivable at 350 kt. and below 5,000 ft,” this pilot noted. The ET302 crew climbed through 5,000 ft. shortly after de-powering the trim motors, and got to about 8,000 ft.—the same amount of altitude the U.S. crew used up during the roller-coaster maneuvers—before the final dive. A second pilot not involved in the session but who reviewed the scenario’s details said it highlighted several training opportunities. “This is the sort of simulator experience airline crews need to gain an understanding of how runaway trim can make the aircraft very difficult to control, and how important it is to rehearse use of manual trim inputs,” this pilot said. While Boeing’s runaway stabilizer checklist does not specify it, the second pilot recommended a maximum thrust of 75% N1 and a 4 deg. nose-up pitch to keep airspeed under control. Boeing is developing modifications to MCAS, as well as additional training. Simulator sessions are expected to be integrated into recurrent training, and may be required by some regulators, and opted for by some airlines, before pilots are cleared to fly MAXs again. The MAX fleet has been grounded since mid-March, a direct result of the two accidents.
  4. ALPA: Simulator Time Not Needed To Un-Ground 737 MAX May 8, 2019 Sean Broderick | Aviation Daily WASHINGTON—The world’s largest pilots’ union will not ask FAA to require additional mandatory simulator training on maneuvering characteristics augmentation system (MCAS) scenarios for 737 MAX pilots before they can fly, but will recommend it as part of routine recurrent training, Aviation Week has learned. The Air Line Pilots Association (ALPA) will make its views known in comments on a draft of proposed minimum 737 training standards out for public comment. The Flight Standardization Board (FSB) draft report does not recommend simulator sessions as part of transition training for 737 Next Generation pilots upgrading to the MAX, opting for less costly computer-based training instead. A person with knowledge of ALPA’s comments tells Aviation Week that the pilots’ union will go a step further, calling for hands-on simulator training at the earliest scheduled opportunity. Under this scenario, MAX pilots would fly simulated MCAS-related scenarios within a year or so as MAX simulators become available, but not before they return to line operations once flight restrictions on the model are lifted. Some regulators are expected to require simulator training as conditions for removing their operations bans, and Air Canada has said it is already using its MAX simulator—the only one in airline hands in North America—to run its 420 MAX pilots through MCAS-related scenarios. ALPA’s training recommendations will include other additions to the draft document as well—most of them emphasizing MCAS-related differences between the NG and the MAX. The MCAS was needed for certification purposes to enhance pitch stability with slats and flaps retracted at very light weights and full aft center-of gravity (CG), ensuring the MAX handled like the NG. The system activates when the aircraft’s speed approaches threshold AOA, or stick-shaker stall-warning activation, for the aircraft’s configuration and flight profile. The union wants the AOA Disagree alert message and its relation to MCAS added to items given “special emphasis” in MAX training. The MCAS is fed by angle of attack (AOA) data, and activates when the data shows the aircraft’s nose as being too high for the current flight profile. ALPA wants pilots to understand the link between AOA Disagree alerts, which will now be standard on primary flight displays for all MAXs, and the MCAS’s role of automatically moving the horizontal stabilizer to compensate for an AOA approaching aerodynamic stall. The union also wants MAX pilots to understand that nose-down stabilizer trim applied by MCAS cannot be countered by pulling back on the yokes. The MCAS is an extension of the 737 speed trim system (STS), which automatically moves the stabilizer to ensure pitch is maintained as speed increases. On the NG, stick force inputs override runaway trim, including the STS runaways. On the MAX, stick force overrides all runaway trim conditions, but not MCAS. Boeing determined that allowing the MCAS to be countered by pulling back on the yoke could negate its purpose, so the column brake is bypassed when the MCAS is activated. Instead, the MCAS can be countered using yoke-mounted electric trim switches or, in extreme conditions, by toggling cutout switches that de-power the trim motors and using hand-cranked trim wheels. The public has until May 15 to comment on the draft FSB report. Approving it will be a key step in getting the MAX fleet back in the air, along with having regulators sign off on changes to the MCAS software that Boeing is finalizing. FAA said it will consider the public’s input before making a final decision on the FSB’s contents. “We are looking forward to reviewing all of the comments,” the agency said. The Air Line Pilots Association did not immediately respond to a request for comment. Regulators grounded the 370-aircraft operational fleet in mid-March following the second of two fatal MAX 8 accidents. The MCAS’s erroneous activation played a role in each accident. Boeing is modifying the system’s logic by adding triple redundant angle of attack validity checks to add data redundancy and reduce its authority to activate multiple times in certain scenarios and by limiting its stabilizer command authority to a single, proportionate nose down trim input. Boeing designed the MCAS to operate in the background and only if the aircraft were being operating in a small corner of the flight envelope. Both the company and the original FSB that worked on the model’s 2017 certification determined that special training on the system’s operation was not necessary. As a result, the system was not covered in flight manuals. The updates will add information on the system’s operation. Boeing and the 2017 FSB team also determined that pilots would recognize an MCAS-related failure as stabilizer runaway—a common air transport issue that pilots are trained to manage with a memorized checklist. But in both MAX 8 accident sequences, the crew did not immediately diagnose the MCAS inputs, trigged by erroneous AOA data, as stabilizer runaway. They countered the MCAS with manual electric trim inputs, which re-set the MCAS and caused it to activate again based on the continued stream of faulty AOA data. Had the crews not used the electric trim, the MCAS system would not have activated repeatedly, eventually leading to uncontrollable dives. Boeing’s software update removes this function so that electric trim does not re-set MCAS so that it cannot operate again based on faulty data. ALPA, which represents pilots at MAX operators United Airlines and WestJet, also will advise that pilots practice as many MCAS-failure-related emergency scenarios as necessary to demonstrate competency. Boeing’s explanation of MCAS following the first accident, Lion Air Flight 610 in October 2018, listed nine related “indications and effects” that could result from an AOA Disagree alert and possible MCAS activation. While the FSB still must be finalized, mandatory simulator training before qualified 737NG pilots fly the MAX is not expected to be part of the package. “At this point, we’re not hearing that [simulator training] will be a requirement,” Southwest Airlines CEO Gary Kelly said recently. “Just getting pilots back into the simulator for an event would be a challenge, and that would take time. But my own interpretation is that we already do the kind of training that one would be contemplating to put the MAX back into service. Managing the aircraft in a runaway stabilizer scenario is something that we already trained on and…has already been covered.”
  5. A timely examination of a topic relevant to these two accidents: https://www.researchgate.net/publication/332686552_The_Role_of_Alerting_System_Failures_in_Loss_of_Control_Accidents_CAST_SE-210_Output_2_Report_3_of_6/download The Role of Alerting System Failures in Loss of Control Accidents CAST SE-210 Output 2 Report 3 of 6 Randall J. Mumaw1, Loran A. Haworth1, and Michael S. Feary2 Executive Summary This report is part of a series of reports that address flight deck design and evaluation, written as a response to loss of control accidents. In particular, this activity is directed at failures in airplane state awareness in which the pilot loses awareness of the airplane’s energy state or attitude and enters an upset condition. In a report by the Commercial Aviation Safety Team, an analysis of accidents and incidents related to loss of airplane state awareness determined that hazard alerting was not effective in producing the appropriate pilot response to a hazard (CAST, 2014). In the current report, we take a detailed look at 28 airplane state awareness accidents and incidents to determine how well the hazard alerting worked. We describe a five-step integrated alerting-to-recovery sequence that prescribes how hazard alerting should lead to effective flight crew actions for managing the hazard. Then, for each hazard in each of the 28 events, we determine if that sequence failed and, if so, how it failed. The results show that there was an alerting failure in every one of the 28 safety events, and that the most frequent failure (20/28) was tied to the flight crew not orienting to (not being aware of) the hazard. The discussion section summarizes findings and identifies alerting issues that are being addressed and issues that are not currently being addressed. We identify a few recent upgrades that have addressed certain alerting failures. Two of these upgrades address alerting design, but one response to the safety events is to upgrade training for approach to stall and stall recovery. We also describe issues that need additional attention: the need for improved alert integration for flight path management hazards, airplanes in the fleet that do not meet the current alerting regulations, a lack of innovation for addressing cases of channelized attention, and existing vulnerabilities in managing data validity.
  6. blues, I think most passengers don't know what airplane they're in. Safety announcments I've heard mention the type but many don't get the Emergency Card out and read it. I think fares have more impact than aircraft type.
  7. https://www.seattletimes.com/business/boeing-aerospace/faa-could-clear-boeing-max-to-fly-again-by-late-may-or-early-june/?utm_source=marketingcloud&utm_medium=email&utm_campaign=BNA_042619204614+BREAKING%3a+FAA+could+clear+737+MAX+to+fly+again+within+weeks_4_26_2019&utm_term=Active subscriber FAA could clear Boeing 737 MAX to fly again within weeks April 26, 2019 at 1:17 pm Updated April 26, 2019 at 1:46 pm Dominic Gates By Dominic Gates Seattle Times aerospace reporter The Federal Aviation Administration (FAA) could clear Boeing’s 737 MAX to fly again late next month or early June, according to a person familiar with the safety agency’s latest thinking. If the FAA gives the green light that soon — much more quickly than many analysts have predicted — airlines would still need weeks to get their planes ready and their pilots trained. But the timetable, which assumes no unforeseen developments, means U.S. carriers could have the MAX flying passengers again by early August. That likely timeline was confirmed by a second person close to the discussions. At a crucial meeting of the heads of civil-aviation authorities from around the world convened by the FAA on May 23, the U.S. regulatory agency is expected to outline its finalized safety analysis in an attempt to foster international consensus. Unless some new issues are discovered, the FAA anticipates telling the assembled foreign regulators that it’s “in a position to clear the aircraft for service sometime in the near vicinity of that meeting,” potentially as early as a week later, said the person familiar with FAA’s latest thinking. . . . .
  8. TWO great-grandbabies?! How wonderful for you, Greg! Please say hello to your son & family for us. We have 3 GB's, 4, 2 & 4mo...we're often a hundred-and-an-eighth in coloring books, toys & 95-110db these days - ! Yes, the Neo...never understood the switch to a 1966 cable-&-pulley bread-and-butter type. I hope it works out for Boeing, and all the airlines that trusted and bought the airplane, but truly, it's an organizational & design/engineering lesson that never should have needed learning.
  9. Hi Greg; The splash-screen seen here in the link to the video posted by Jaydee is a clear illustration of the change in the engine/cowling arrangement, (a "btw", IEEE is a technical/profession/engineering association of which the gentleman who wrote the article is a member.) From the article: The last statement about the raised thrust line being the cause of the pitch up does not make sense. A thrust line that is closer to the longitudinal centerline of the fuselage does not increase force, it reduces it, so the statement is wrong right away without examining the actual design. The higher thrust line is not the reason MCAS was required. It is stated that the increased area of the engine cowlings providing an increase in lift at higher AoA's. This lift came just at the point where the older Boeings would be providing a heavier control column feel to the pilots, which certification standards, (CFR 25.173, I have seen quoted, pasted below), required. On the MAX, as speed reduced and the stall AoA was approached, a certain, required "pull" on the control column was not evident, so Boeing used the MCAS solution to provide this additional pull, which was necessary if the single B737 "type" was to be retained. They just don't appear to have done an "FMEA" when designing/building the system. MCAS action is intermittent, and if the trim wheels are seen rotating right after takeoff, it's the same as STS, (Speed Trim System) operation which is designed to force the pilot to trim out the artificial-feel forces as speed increases. Since the late 60's, we've been trained to recognize a runaway stabilizer as a continuous event, not an intermitent one with "intervals" of operation, which do not raise awareness, signal danger or provide a hint of what's actually happening, particularly when the crew is trying to determine why the stick shaker is activated and the airspeeds appear unreliable. Cheers as always, Greg!
  10. blues, re, "Interesting scrape marks.", yes, and also on the corner of the aileron, perhaps while it was full-down?...(brrrrrr). I have had the experience, once, of "running out of aileron" in a cross-wind in YYC, (A320) while the airplane kept rolling. It would be at the point where the airplane was likely in Direct Law, and I suspect this A321 was in the process of entering Normal Law...I'd have to get out the books. Oh,...wait,...
  11. It's not possible to know/predict the chances of that happening, but the drill is to hold the trim wheel & re-trim to neutral and continue to trim using the manual trim wheels as required.
  12. Both AoA sensors are used by the FCCs on alternate flight legs. The switch between left & right is accomplished through WoW sensing. One hopes the change includes some resiliency in a brittle system that breaks quickly and badly and instead fails gracefully, permitting crews time to assess what kind of runaway they're dealing with - continuous, or by 5" intervals which mimicks STS behaviour after lift-off. Along with comparison software that stops just the MCAS with an AoA disagreement of say, > 5°, one hopes there is clarity for crews on what the cut-off switches actually do. I believe they're both shut off now in the Runaway drill?
  13. j.k., agree with your comments. Also, at time 2:56, the video misleads viewers on the fundamental reason for the existence of MCAS on the MAX. Quote: "Except, moving the engines up on the 737 had a side effect. When the 737 was at full thrust, like during takeoff, the nose tended to point too far upward which can lead to a stall. This was a problem because these planes were supposed to behave like the old ones." end quote. They show the reason for the engine arrangement on the MAX quite well, but the statement regarding thrust & stalling at takeoff defies physics - moving the thrust line higher and thus closer to the longitudinal center of the fuselage, (or just above the floor-line) reduces, not increases, the effect of thrust line. The reason for MCAS is, the increased cowling area for the LEAP engine produced sufficient lift so as to render too-light a response when the a/c was nearing entry to the stall, (discovered in early flight tests). The reduced 'feel' of the CC did not conform to design standards under which the type was certified (in 1966). To be certifiable under the same type, it had to be demonstrated that the MAX had the same response as all previous B737s. Keeping same type was crucial to the sale of the aircraft. MCAS, which produced the required "heavier" control feel was Boeing's solution. This is all simplified I know. The false statement in the video invites an incorrect conclusion regarding the stall warning/stick shaker at takeoff on both accident aircraft, which occur for entirely different reasons to do with the left AoA sensor and possibly the left FCC.
  14. There is lots of scaffolding, meaning renovations were taking place. https://www.msn.com/en-gb/news/other/notre-dame-cathedral-statues-flown-away-for-renovation/vi-BBVRov0