Thank you so much for posting all of these. I have no connection to aviation except that it's a relatively new interest for me, and I love deep technical dives. Your videos are a wonderful resource.
Hello Chris and thank you so much for this thorough explanation. I consider it really precious because I’m considering coming back to the 737 after a few years spent flying the 787 and it’s crystal clear! I also took the opportunity of buying your amazing 737 technical guide which is such a great ressource ! A huge thank you for what you bring to the 737 community.
Thank you, I really appreciate your kind words and I am glad my explanations have been of use. Welcome back to the 737, you will find it like putting on a comfy old pair of slippers!
Chris - from another Chris, hello, and thanks so much for this channel and especially this presentation. I am upgrading to 737 Captain at a U.S. legacy airline with a HUGE 737 MAX order and cannot thank you enough for your time, expertise, and thorough explanations. You have done a tremendous service to your fellow 737 aviators, and I owe you a pint next time I get to the U.K. Cheers!
This post is two years old as I comment from a layman's viewpoint. Place people under enough pressure, and invariably bad decisions are made. Case in point is the Challenger disaster. Religous child abuse which went on for years, and on and on. Heck, I've been guilty myself. I watched a number of your videos. While your target audience is professionals, I myself find your information so clearly and concisely presented that I "get" probably 95% of it. Kudos.
Hi Philip, yes pressure lies at the heart of many a bad decision, in this case commercial pressure from the rise of Airbus. Thank you for your kind comments about my presentation style, my aim is always to try to make a complex subject understandable.
Amazing lecture and review of the MAX story. Thanks for sharing this Chris! And especially all your other videos aswell. It is a wonderful feeling being able to see the big picture, but unfortunately the walk-around takes a little bit longer now 😅
Hi Chris, this is the best and fairest presentation I have seen on this topic, thank you. Would you have any issues if I quote some of the conclusions in a presentation I intend to provide to the New Zealand Society of Safety Engineering and Engineers New Zealand?
Hi Ben, Thank you for your kind comments. I am happy for you to use any of the material in my presentation or website for your presentation. Good luck! Chris
It's downright spooky how accurate AvE was when he made a quick and dirty analysis of the 737 Max and the MCAS system from his shop over 6 months ago. From the fact that they only had one angle of attack sensor, the warning light considered as optional equipment, pilots and flight crew were not informed of the changes to the flight system at all, And how MCAS could basically trick pilots into pushing their nose down and crashing into the ground. The most disturbing part was the flight data recorder logs that showed the pilot applied 180 lb of back pressure on the control stick, a minute later the plane crashed.
@@ChrisBrady737 .... trust me, I already did! 😉 May you please answer a question for which nobody answered me since: - what is the reason for a limitation we often find on FAR 25/CS 25 certified ACFT, "do not establish a HLD - High Lift Devices and/or gear extended configuration above 20000 ft"? 🤔 My guess is that it maybe has something to do with compressibility & chock waves occurrence at these altitudes, but I never did find any justification for such a limitation. Sorry for asking some of your time here. I am just trying to never stop learning. Many anticipated thanks and best regards. Jalil MACHICHI.
@@7591warthog The reason I heard first hand from Boeing is that at the time of certification there was no anticipated need for HLD above 20,000ft so they did not flight test or certify above 20,000ft. There is no aerodynamic reason, just a legal one!
Hello Chris, I’ve recently discovered your channel and I’m drinking from this fountain like a drunkard on St Patrick’s Day (interviews coming up…) I was due to start my line training on the B737 (after 13 years on the B767) when the second accident happened and the aircraft was grounded. I loved every bit of this presentation and following discussion. Kudos for being so thorough in your exposition of facts. One thing I’d disagree, however, is the part where you state that the crews acted correctly. Both situations were admittedly nightmare scenarios, but in our NG simulator our TRIs managed to simulate them by simultaneously triggering runaway stab trim and airspeed disagree. As you very well know the first actions in the stab trim are to block the trim. The Lion crew NEVER touched the cut-off switches, afaik. For the airspeed disagree the first actions are to disconnect A/T, A/P and FDs. None of these actions were performed by either crew, nor was control ever given to the FOs, even though it was clear that the offending IAS was the Captain’s. So, no, unless some more evidence to the contrary comes about crews’ actions, it cannot be honestly said they performed the required QRH actions. I understand that the stick shaker, all the lights, bells and warnings going off in the flight deck were extremely distracting, but that’s why we spend so much time in the sim and that they pay us pilots so much, isn’t it? Oh, wait…
The MAX accidents were not runaway trim events, they were intermittent short uncommanded applications of stab trim. Whenever electric stab trim was applied by the crew the condition stopped (for 5s) making the crew believe that that part of the multiple failure had been addressed. The airspeed disagree, stall warning and various other master cautions (see my video for details) being the other components. Simply setting up a conventional stab trim runaway and an airspeed disagree in the sim does not come anywhere close to what those crews had.
@@ChrisBrady737 I understand what you say. The NG does not have MCAS and MCAS intervention in both cases was different from a pure vanilla runaway stab trim. But imho, not knowing about MCAS, one should interpret the intermittent activation of nose down trim as a weird case of runaway trim. If caught early they could have maintained the aircraft under control. The safest course of action was to flip the trim cut off switches. That's out of pure airmanship, not procedure. Only the Ethiopian FO did it, but far too late to recover. My point is that neither crew acted correctly. The "Airspeed disagree" memory items were never performed, despite "IAS DISAGREE" being shown on the displays. So, imho, both crews lacked airmanship and did not act correctly. Bear in mind, I'm not faulting the crews, they did the best they could at the moment, given the chaotic environment they were in and the training they received during their piloting careers. But they failed to react correctly to at least one checklist (Airspeed unreliable). The blame for this mess from the crew reaction standpoint (setting aside everything else) is to be placed in their airlines and the lack of focus on piloting skills, situational awareness and airmanship in their training. You know better than I do that airlines see training as a cost, rather than an investment, so they try everything they can to spend the smallest amount of money possible on training, barely clearing the minimum required by law. The end result is what the FAA has called "lack of basic piloting skills" (the expression came out in the news after the AF447 accident off the coast of Brazil). Unfortunately most airlines nowadays don't want pilots, they want procedure-followers, checklist-readers and button-pushers. That is all fine and dandy if everything remains within the boundaries of what crews can expect and of what the engineers thought of. But Mother Nature is a bitch and always finds the flaws even in perfectly designed systems. That is why we need pilots, real pilots, in the flight decks of aircraft, not automatons who can't stray from the marked path.
Re the "How did MCAS come about" slide @ 12m31s, the last part about the assessments not being updated and the FAA not being informed... There very well could be an update I'm missing or some context I'm unaware of, but the JT610 final report seems to contradict these points on page 271: "An NTSB review of Appendix “G” found that the introductory section of SSA had not been updated to reflect the March 2016 MCAS maximum authority changes. The introductory section indicated that MCAS was added on the 737 MAX to address potentially unacceptable nose-up pitching moment at high angles of attack at high airspeeds; there was no mention that MCAS had been revised to improve flaps up, low Mach tall characteristics and identification. Additionally, the functional hazard assessment summary table contained within the Appendix still reflected a pre-March 2016 MCAS maximum authority limit of 0.6 degrees. However, an NTSB review of Boeing internal documents confirmed that the FHAs had in fact been reassessed each time that the MCAS requirements were changed, including the change in authority limit from 0.6 to 2.5 degrees. In all cases, the reassessment found that the FHA categories had not changed."
I have been pondering the decision by Boeing engineering to use only one AOA sensor at a time when it will have large control of the elevator. It couldn't have been due to cost savings because the extra cost would be very small. It had to be due to ignorance of some basic automatic flight control system AFCS principals that have been understood even by many of us technician s for well over 60 years. How do people that are ignorant of the basics get into positions of approval authority? All I know is that I have seen a lot of that type of thing in my 40 years working with military aircraft as a military person for ten years and thirty years as a tech rep. I have seen many get promoted who were not competent in their present job. Knowledge of one's job does not seem to be a requirement for promotion anywhere.
sir, also you mentioned that the topic of 'pilot training' deserves a whole new presentation. Looking forward for another lecture and you thoughts on this matter!
change management - critical. There must be transparency on significant changes to an aircraft systems that results in a system safety assessment changes. It astonishes me that this imperative was either downplayed, ignored or discarded
Good Day Capt Brady, 1.Are you feel confidence and safe to fly this 737 max again after Boeing changed the mcas software and mcas system to refer to 2 AOA sensor as an experienced pilot? 2. Short after the 2nd crash ethiopian airlines some news pop up to point at Boeing 737max flaws in design. They mention that in some situation this new LEAP engine can create additional Lift but this lift vector is about in front of the CG(Center of Gravity) so with this addition Lift it creates a little torque(increase the magnitude of horizontal stab downforce). This result will raise the airplane nose up. That why boeing come out with idea to create an assistant software MCAS to counteract this nose up. Some idea also exist that Boeing has to redesign the whole tail(vertical and horizontal stabilizer included elevator and rudder). This redesign will cost Boeing a lot of time for certification of new part through FAA. Do you think this redesign of whole tail will help to solve this problem? 3. If let say we redesign main wing which we increased wing span area A s much as old wing with flap 5.Do you think this idea could also work to solve this problem with the additional lift from new LEAP engine?
A1 I answered in the video at 1:07:13 A2 I don't think that a redesign of the whole tail was necessary but I dont have the aerodynamic data to confirm this. A3 Again, I don't have the aerodynamic data to answer that question.
Thanks Mike. No, disengaging A/P is actually one of the criteria for MCAS activation. Se my other video "MCAS in detail on the 737 MAX" th-cam.com/video/bljlduBx1TE/w-d-xo.html
Hi Chris. Many thanks for putting the videos together. I don't know where to post this question and since it is about the MAX displays this maybe a good place. Being an NG and MAX operator I am very dismayed with the MAX "font" size and dual channel cues not being the same size as the NGs. Do you know why the MAX has all the "real estate" yet the symbology is smaller? Thanks.
Hi - on slide 17, there's mention of a synthetic AoA to be implemented as part of the release of Max10. I believe that Max10 has been cancelled, however, so does this have an implication to the implementation of the synthetic AoA?
Looks like my info was stale or incomplete. There was special dispensation required from US Congress in order to facilitate the type approval for the -10 post a certain date (2023-12-31?). At one point, there was concern regarding whether the -10 would make it to first flight prior to this date and what the implications would be WRT the -10. Perhaps Chris has some detail on this?
@@roscozone8092 The -10 is still going strong. Certification has been delayed by slower processes following the FAAs tightening of procedures following the MCAS accidents. After over 1,000 hours or experimental flight testing, certification flight testing with the FAA began 22 Nov 2023. Certification is expected late 2024 or early 2025.
Hi Chris, I did some digging - a summary of what I found: Following on from the two MAX accidents, the "Aircraft Certification, Safety, and Accountability Act" required that new transport category types and subtypes would require enhanced crew alerting via an EICAS system. This legislation came into effect on 2022-12-31(*), with all new transport category type certificates (and supplemental type certificates) needing to comply with this legislation. This requirement would have resulted in major differences between -8 and -9 (which were certified under prior regulatory requirements and not required to have EICAS), and the -7 and -10, which would have required EICAS, due to their later anticipated certification dates. This would have meant that either that: 1. - The -7 and -10 would have required a new type certification (and aircrews would have had to be certified separately on both the -8 and -9 and again on the -7 and -10); or 2 - The entire existing fleet of MAX -8 and -9 aircraft would have had to have been retrofitted with EICAS and, again, would likely have resulted in the entire MAX series needing a new type certificate, not just a supplemental and crew difference training between Originals, Classics, NGs and MAX subtypes would have been more involved. In other words, there would have been a line of division for operators, either between the -8 & -9 and the -7 and -10 or between the MAX series and all other 737s. It would have been messy. The MAX had been intended as an "easy" option for operators. The intention for aircrews and maintenance personnel to be able to switch between subtypes with minimal difference training would have been negated unless a way could have been found around the legislation. Pilot unions (Allied Pilots' Association) supported the introduction of EICAS, likely following on from the uncertainties following on from the MCAS accidents. In 2022-07, Calhoun stated that Boeing could be forced to cancel the new MAX subtypes over potential regulatory issues. Boeing's filing to Congress stated that if the deadline was not extended and it did not win certification it might choose to discontinue the -7 and -10. American Airlines' and Boeing's position was that disparate alerting systems between subtypes would be more likely to introduce safety issues, rather than eliminate them. Senator Cantwell proposed that the MAX -7 and -10 should be exempt from the requirements of the aircrew alerting requirements under the new Aircraft Certification, Safety, and Accountability Act. Thankfully, some common sense prevailed and Congress granted the exemption for the -7 and -10. As a result, the -7 and -10 will be type certified with the older style recall alterting system rather than with EICAS in order to retain commonality across the fleet. Regards, Ross (*) Earlier than I'd thought - I'd thought it was at the end of 2023, hence I found locating documentation trickier than I'd anticipated.
I have often seen it stated in internet comments that given the scrutiny the 737 Max has undergone, it is now the safest airliner in the sky. This is patently false. All we can say with certainty is that the airplane meets regulatory safety requirements for its certified use, and that its strengths and weaknesses are well understood. Truly modern airliners have fundamentally safer levels of redundancy and capability because they were designed and built using more modern systems, materials, standards, and methods. This comment is not intended to denigrate the safety of the 737 Max, only to point out that heavily scrutinizing an old system and fixing its flaws doesn't make it inherently safer than a well designed system built to modern standards.
I guess one counter argument would be that the 737 has had 50+ years of life to discover and rectify any initial design flaws, thereby making it the most tried and tested airliner.
@@6z0 yes and... No. The lack of QA is obviously a consequence of 737 max production lines having difficulties being profitable after all the 737 max program choices are backfiring. From design to modifications, delayed rework on undelivered planes, supply chain management (and aggressive financial pressure on it), market shifts after loss of trust, etc. We can say it's not a direct 737 max problem but they both (actually we can add 787 and 777-X woes) come from the same root.
28:00 couldn't they have just dealt with the IAS disagree with using memory pitch power. iirc one of the pilots on the Ethiopian kept trying to engage the AP. Then upon identifying the stab trim runaway gone for stab trim cutout? Was the stab trim runaway hard to identify because runaway was periodic? In both transcripts iirc (especially evident for the Ethiopian), both crews seemed to fixated on flying the planned route and complying with ATC rather than flying the plane. Imo the lion air guys had the worst situation of the 2 (information overload)
Of course, from the comfort of or desks, it is easy to say that there were many things that both the Lion Air and Ethiopian crews could have done differently. But they were facing multiple sometimes conflicting signals from an undocumented, untrained system. I find it difficult to criticise their actions.
It’s tragic 364 people died as a result of a financial decision that could only have come from the top. A lot of money must have changed hands prior to these accidents to allow this serious problem to slip through the net.
![[ENGSUB] UNPRODUCTIVE DAY ใช้ชีวิต (เปื่อยๆ) ด้วยกัน 1 วัน! | OUROAD CLOSEFRiEND SS2 EP.9](http://i.ytimg.com/vi/pyYKZ3kra9w/mqdefault.jpg)
Hello Chris. Thank you for making this available. This is a great contribution for the understanding of this very important issue.
Hi Eduardo, you are very welcome. Please check out my presentation on MCAS in depth and please subscribe to my channel to catch future presentations.
@@ChrisBrady737 certainly. Already subscribed and watching the in depth video. Thanks Chris.
Thank you so much for posting all of these. I have no connection to aviation except that it's a relatively new interest for me, and I love deep technical dives. Your videos are a wonderful resource.
Thak you Capt. Brady for your brillant contribution to our safety as airline pilots. Greetings.
Greetings and thank you for watching
Hello Chris and thank you so much for this thorough explanation. I consider it really precious because I’m considering coming back to the 737 after a few years spent flying the 787 and it’s crystal clear! I also took the opportunity of buying your amazing 737 technical guide which is such a great ressource ! A huge thank you for what you bring to the 737 community.
Thank you, I really appreciate your kind words and I am glad my explanations have been of use. Welcome back to the 737, you will find it like putting on a comfy old pair of slippers!
Chris - from another Chris, hello, and thanks so much for this channel and especially this presentation. I am upgrading to 737 Captain at a U.S. legacy airline with a HUGE 737 MAX order and cannot thank you enough for your time, expertise, and thorough explanations. You have done a tremendous service to your fellow 737 aviators, and I owe you a pint next time I get to the U.K. Cheers!
Hi Chris, thank you very much for your kind words. It is feedback like this that makes it all worthwhile. Good luck with your command 🍻
This post is two years old as I comment from a layman's viewpoint. Place people under enough pressure, and invariably bad decisions are made.
Case in point is the Challenger disaster. Religous child abuse which went on for years, and on and on. Heck, I've been guilty myself.
I watched a number of your videos. While your target audience is professionals, I myself find your information so clearly and concisely presented that I "get" probably 95% of it. Kudos.
Hi Philip, yes pressure lies at the heart of many a bad decision, in this case commercial pressure from the rise of Airbus. Thank you for your kind comments about my presentation style, my aim is always to try to make a complex subject understandable.
Amazing lecture and review of the MAX story. Thanks for sharing this Chris! And especially all your other videos aswell.
It is a wonderful feeling being able to see the big picture, but unfortunately the walk-around takes a little bit longer now 😅
Thank you for your kind comments, good to hear that you enjoyed the videos.
Hi Chris, this is the best and fairest presentation I have seen on this topic, thank you. Would you have any issues if I quote some of the conclusions in a presentation I intend to provide to the New Zealand Society of Safety Engineering and Engineers New Zealand?
Hi Ben, Thank you for your kind comments. I am happy for you to use any of the material in my presentation or website for your presentation. Good luck! Chris
Nice explanation Captain. Greetings from Panama.
Glad you liked it!
It's downright spooky how accurate AvE was when he made a quick and dirty analysis of the 737 Max and the MCAS system from his shop over 6 months ago.
From the fact that they only had one angle of attack sensor, the warning light considered as optional equipment, pilots and flight crew were not informed of the changes to the flight system at all, And how MCAS could basically trick pilots into pushing their nose down and crashing into the ground.
The most disturbing part was the flight data recorder logs that showed the pilot applied 180 lb of back pressure on the control stick, a minute later the plane crashed.
The whole MCAS episode was tragic and avoidable if enough consideration had been given to the design.
Outstanding presentation. Very interesting & thourough explanations.
Thanks for watching, check out my other videos and tell your colleagues
@@ChrisBrady737
.... trust me, I already did! 😉
May you please answer a question for which nobody answered me since:
- what is the reason for a limitation we often find on FAR 25/CS 25 certified ACFT, "do not establish a HLD - High Lift Devices and/or gear extended configuration above 20000 ft"? 🤔
My guess is that it maybe has something to do with compressibility & chock waves occurrence at these altitudes, but I never did find any justification for such a limitation.
Sorry for asking some of your time here. I am just trying to never stop learning.
Many anticipated thanks and best regards.
Jalil MACHICHI.
@@7591warthog The reason I heard first hand from Boeing is that at the time of certification there was no anticipated need for HLD above 20,000ft so they did not flight test or certify above 20,000ft. There is no aerodynamic reason, just a legal one!
@@ChrisBrady737
.... again, I really thank you for all this.
Regards,
Jalil MACHICHI.
Hello Chris,
I’ve recently discovered your channel and I’m drinking from this fountain like a drunkard on St Patrick’s Day (interviews coming up…)
I was due to start my line training on the B737 (after 13 years on the B767) when the second accident happened and the aircraft was grounded.
I loved every bit of this presentation and following discussion. Kudos for being so thorough in your exposition of facts.
One thing I’d disagree, however, is the part where you state that the crews acted correctly. Both situations were admittedly nightmare scenarios, but in our NG simulator our TRIs managed to simulate them by simultaneously triggering runaway stab trim and airspeed disagree. As you very well know the first actions in the stab trim are to block the trim. The Lion crew NEVER touched the cut-off switches, afaik. For the airspeed disagree the first actions are to disconnect A/T, A/P and FDs. None of these actions were performed by either crew, nor was control ever given to the FOs, even though it was clear that the offending IAS was the Captain’s. So, no, unless some more evidence to the contrary comes about crews’ actions, it cannot be honestly said they performed the required QRH actions.
I understand that the stick shaker, all the lights, bells and warnings going off in the flight deck were extremely distracting, but that’s why we spend so much time in the sim and that they pay us pilots so much, isn’t it? Oh, wait…
The MAX accidents were not runaway trim events, they were intermittent short uncommanded applications of stab trim. Whenever electric stab trim was applied by the crew the condition stopped (for 5s) making the crew believe that that part of the multiple failure had been addressed. The airspeed disagree, stall warning and various other master cautions (see my video for details) being the other components. Simply setting up a conventional stab trim runaway and an airspeed disagree in the sim does not come anywhere close to what those crews had.
@@ChrisBrady737 I understand what you say. The NG does not have MCAS and MCAS intervention in both cases was different from a pure vanilla runaway stab trim. But imho, not knowing about MCAS, one should interpret the intermittent activation of nose down trim as a weird case of runaway trim. If caught early they could have maintained the aircraft under control. The safest course of action was to flip the trim cut off switches. That's out of pure airmanship, not procedure. Only the Ethiopian FO did it, but far too late to recover.
My point is that neither crew acted correctly. The "Airspeed disagree" memory items were never performed, despite "IAS DISAGREE" being shown on the displays.
So, imho, both crews lacked airmanship and did not act correctly.
Bear in mind, I'm not faulting the crews, they did the best they could at the moment, given the chaotic environment they were in and the training they received during their piloting careers. But they failed to react correctly to at least one checklist (Airspeed unreliable).
The blame for this mess from the crew reaction standpoint (setting aside everything else) is to be placed in their airlines and the lack of focus on piloting skills, situational awareness and airmanship in their training. You know better than I do that airlines see training as a cost, rather than an investment, so they try everything they can to spend the smallest amount of money possible on training, barely clearing the minimum required by law. The end result is what the FAA has called "lack of basic piloting skills" (the expression came out in the news after the AF447 accident off the coast of Brazil).
Unfortunately most airlines nowadays don't want pilots, they want procedure-followers, checklist-readers and button-pushers. That is all fine and dandy if everything remains within the boundaries of what crews can expect and of what the engineers thought of.
But Mother Nature is a bitch and always finds the flaws even in perfectly designed systems.
That is why we need pilots, real pilots, in the flight decks of aircraft, not automatons who can't stray from the marked path.
Re the "How did MCAS come about" slide @ 12m31s, the last part about the assessments not being updated and the FAA not being informed... There very well could be an update I'm missing or some context I'm unaware of, but the JT610 final report seems to contradict these points on page 271:
"An NTSB review of Appendix “G” found that the introductory section of SSA had not been updated to reflect the March 2016 MCAS maximum authority changes. The introductory section indicated that MCAS was added on the 737 MAX to address potentially unacceptable nose-up pitching moment at high angles of attack at high airspeeds; there was no mention that MCAS had been revised to improve flaps up, low Mach tall characteristics and identification. Additionally, the functional hazard assessment summary table contained within the Appendix still reflected a pre-March 2016 MCAS maximum authority limit of 0.6 degrees.
However, an NTSB review of Boeing internal documents confirmed that the FHAs had in fact been reassessed each time that the MCAS requirements were changed, including the change in authority limit from 0.6 to 2.5 degrees. In all cases, the reassessment found that the FHA categories had not changed."
I have been pondering the decision by Boeing engineering to use only one AOA sensor at a time when it will have large control of the elevator. It couldn't have been due to cost savings because the extra cost would be very small. It had to be due to ignorance of some basic automatic flight control system AFCS principals that have been understood even by many of us technician s for well over 60 years. How do people that are ignorant of the basics get into positions of approval authority? All I know is that I have seen a lot of that type of thing in my 40 years working with military aircraft as a military person for ten years and thirty years as a tech rep. I have seen many get promoted who were not competent in their present job. Knowledge of one's job does not seem to be a requirement for promotion anywhere.
Thank you for your robust explanation ! The Aviation Comunity needs to share Knowledge . Grazie
Glad it was helpful!
sir, also you mentioned that the topic of 'pilot training' deserves a whole new presentation. Looking forward for another lecture and you thoughts on this matter!
For the time being I will concentrate on technical areas of the 737 before addressing that issue.
thank you for this truly insightful lecture, captain!
Glad you enjoyed it!
Thanks Chris - excellent review.
My pleasure, I hope you found it useful.
change management - critical. There must be transparency on significant changes to an aircraft systems that results in a system safety assessment changes. It astonishes me that this imperative was either downplayed, ignored or discarded
I couldn’t agree with you more.
Good Day Capt Brady,
1.Are you feel confidence and safe to fly this 737 max again after Boeing changed the mcas software and mcas system to refer to 2 AOA sensor as an experienced pilot?
2. Short after the 2nd crash ethiopian airlines some news pop up to point at Boeing 737max flaws in design. They mention that in some situation this new LEAP engine can create additional Lift but this lift vector is about in front of the CG(Center of Gravity) so with this addition Lift it creates a little torque(increase the magnitude of horizontal stab downforce). This result will raise the airplane nose up. That why boeing come out with idea to create an assistant software MCAS to counteract this nose up. Some idea also exist that Boeing has to redesign the whole tail(vertical and horizontal stabilizer included elevator and rudder). This redesign will cost Boeing a lot of time for certification of new part through FAA. Do you think this redesign of whole tail will help to solve this problem?
3. If let say we redesign main wing which we increased wing span area A s much as old wing with flap 5.Do you think this idea could also work to solve this problem with the additional lift from new LEAP engine?
A1 I answered in the video at 1:07:13
A2 I don't think that a redesign of the whole tail was necessary but I dont have the aerodynamic data to confirm this.
A3 Again, I don't have the aerodynamic data to answer that question.
Is there a layer of "distorted sound noise" in the background in the background? Am I the only one who hears it?
Excellent presentation
Thank you, glad you enjoyed it
Excellent channel Chris, does disengaging auto pilot also disengage mcas, (stab trim cutout in normal position)?
Thanks Mike. No, disengaging A/P is actually one of the criteria for MCAS activation. Se my other video "MCAS in detail on the 737 MAX" th-cam.com/video/bljlduBx1TE/w-d-xo.html
@@ChrisBrady737 Thanks Chris, is this the case pre and post fix?
Yes, it was not changed
Hi Chris. Many thanks for putting the videos together. I don't know where to post this question and since it is about the MAX displays this maybe a good place. Being an NG and MAX operator I am very dismayed with the MAX "font" size and dual channel cues not being the same size as the NGs. Do you know why the MAX has all the "real estate" yet the symbology is smaller? Thanks.
Hi Pauly, yes good point, especially for those of us starting to need glasses! I have no idea why they did this.
Very thorough. Thank you
Glad it was helpful!
Hi - on slide 17, there's mention of a synthetic AoA to be implemented as part of the release of Max10. I believe that Max10 has been cancelled, however, so does this have an implication to the implementation of the synthetic AoA?
AFAIK the MAX 10 has not been cancelled.
Not really buddy, Indian airline Akasa placed an order 150 max's which include the max-10, TODAY.
Looks like my info was stale or incomplete. There was special dispensation required from US Congress in order to facilitate the type approval for the -10 post a certain date (2023-12-31?). At one point, there was concern regarding whether the -10 would make it to first flight prior to this date and what the implications would be WRT the -10. Perhaps Chris has some detail on this?
@@roscozone8092 The -10 is still going strong. Certification has been delayed by slower processes following the FAAs tightening of procedures following the MCAS accidents. After over 1,000 hours or experimental flight testing, certification flight testing with the FAA began 22 Nov 2023. Certification is expected late 2024 or early 2025.
Hi Chris,
I did some digging - a summary of what I found:
Following on from the two MAX accidents, the "Aircraft Certification, Safety, and Accountability Act" required that new transport category types and subtypes would require enhanced crew alerting via an EICAS system. This legislation came into effect on 2022-12-31(*), with all new transport category type certificates (and supplemental type certificates) needing to comply with this legislation.
This requirement would have resulted in major differences between -8 and -9 (which were certified under prior regulatory requirements and not required to have EICAS), and the -7 and -10, which would have required EICAS, due to their later anticipated certification dates. This would have meant that either that:
1. - The -7 and -10 would have required a new type certification (and aircrews would have had to be certified separately on both the -8 and -9 and again on the -7 and -10); or
2 - The entire existing fleet of MAX -8 and -9 aircraft would have had to have been retrofitted with EICAS and, again, would likely have resulted in the entire MAX series needing a new type certificate, not just a supplemental and crew difference training between Originals, Classics, NGs and MAX subtypes would have been more involved.
In other words, there would have been a line of division for operators, either between the -8 & -9 and the -7 and -10 or between the MAX series and all other 737s. It would have been messy.
The MAX had been intended as an "easy" option for operators. The intention for aircrews and maintenance personnel to be able to switch between subtypes with minimal difference training would have been negated unless a way could have been found around the legislation.
Pilot unions (Allied Pilots' Association) supported the introduction of EICAS, likely following on from the uncertainties following on from the MCAS accidents. In 2022-07, Calhoun stated that Boeing could be forced to cancel the new MAX subtypes over potential regulatory issues. Boeing's filing to Congress stated that if the deadline was not extended and it did not win certification it might choose to discontinue the -7 and -10. American Airlines' and Boeing's position was that disparate alerting systems between subtypes would be more likely to introduce safety issues, rather than eliminate them.
Senator Cantwell proposed that the MAX -7 and -10 should be exempt from the requirements of the aircrew alerting requirements under the new Aircraft Certification, Safety, and Accountability Act. Thankfully, some common sense prevailed and Congress granted the exemption for the -7 and -10.
As a result, the -7 and -10 will be type certified with the older style recall alterting system rather than with EICAS in order to retain commonality across the fleet.
Regards,
Ross
(*) Earlier than I'd thought - I'd thought it was at the end of 2023, hence I found locating documentation trickier than I'd anticipated.
In regards to the 2 accidents, how would the Integrated Standby Flight Display been behaving when all this hell was breaking loose?
It should have been behaving normally.
I have often seen it stated in internet comments that given the scrutiny the 737 Max has undergone, it is now the safest airliner in the sky. This is patently false. All we can say with certainty is that the airplane meets regulatory safety requirements for its certified use, and that its strengths and weaknesses are well understood.
Truly modern airliners have fundamentally safer levels of redundancy and capability because they were designed and built using more modern systems, materials, standards, and methods.
This comment is not intended to denigrate the safety of the 737 Max, only to point out that heavily scrutinizing an old system and fixing its flaws doesn't make it inherently safer than a well designed system built to modern standards.
I guess one counter argument would be that the 737 has had 50+ years of life to discover and rectify any initial design flaws, thereby making it the most tried and tested airliner.
Thank you Sir
Most welcome
Thanks!
Thank you Philip, much appreciated
20,000,000,000 dollars later, there are still issues.
not really. the plug door is a boeing problem, not a max specific defect.
@@6z0 yes and... No.
The lack of QA is obviously a consequence of 737 max production lines having difficulties being profitable after all the 737 max program choices are backfiring.
From design to modifications, delayed rework on undelivered planes, supply chain management (and aggressive financial pressure on it), market shifts after loss of trust, etc.
We can say it's not a direct 737 max problem but they both (actually we can add 787 and 777-X woes) come from the same root.
Stick Back pressure?
28:00 couldn't they have just dealt with the IAS disagree with using memory pitch power. iirc one of the pilots on the Ethiopian kept trying to engage the AP. Then upon identifying the stab trim runaway gone for stab trim cutout? Was the stab trim runaway hard to identify because runaway was periodic? In both transcripts iirc (especially evident for the Ethiopian), both crews seemed to fixated on flying the planned route and complying with ATC rather than flying the plane. Imo the lion air guys had the worst situation of the 2 (information overload)
Of course, from the comfort of or desks, it is easy to say that there were many things that both the Lion Air and Ethiopian crews could have done differently. But they were facing multiple sometimes conflicting signals from an undocumented, untrained system. I find it difficult to criticise their actions.
It’s tragic 364 people died as a result of a financial decision that could only have come from the top.
A lot of money must have changed hands prior to these accidents to allow this serious problem to slip through the net.
Some people should be in jail for this