Boeing 737 Max - Page 2
Close
Login to Your Account
Page 2 of 58 FirstFirst 12341252 ... LastLast
Results 21 to 40 of 1148

Thread: Boeing 737 Max

  1. #21
    Join Date
    Apr 2006
    Location
    Manchester, England
    Posts
    8,250
    Post Thanks / Like
    Likes (Given)
    1200
    Likes (Received)
    5223

    Default

    Quote Originally Posted by barbter View Post
    Yes - this was in the US but I cannot remember the actual case.
    But it set president that there is a maximum payout per person for an aircrash.
    And then it's easy to do a cost compare against fix versus crash/payout.

    All this said, I would always want to fly in a Boeing over a Scarebus.
    I don't know if it has changed, but up to only a couple of years ago, Airbus will never allow full control to the pilot where Boeing will.
    I could have this wrong but I think the aircraft concerned in this case was a 747.

    To get back to the recent crashes. There must be something drastically wrong with the flight control systems when two nearly brand new aircraft being flown by experienced air crews dive straight in the sea/earth shortly after take off. That can't just be a co-incidence surely. I'm not sure I'd be happy flying in a 737 Max until this is sorted out.

    CNC aircraft ought to be more reliable than CNC machine tools but how many CNC ops on here haven't had a significant crash ?

    Was it in the film " Dark Star " that one of the computer controlled bombs onboard refused to not explode when it got stuck in the bomb bay ?

    Regards Tyrone.

  2. Likes cyanidekid liked this post
  3. #22
    Join Date
    May 2010
    Country
    DENMARK
    Posts
    3,374
    Post Thanks / Like
    Likes (Given)
    4030
    Likes (Received)
    12604

    Default

    Quote Originally Posted by Tyrone Shoelaces View Post
    I'm not sure I'd be happy flying in a 737 Max until this is sorted out.
    Regards Tyrone.
    Read today that China has grounded all Chinese owned 737-800 MAXs until further notice.

  4. #23
    Join Date
    Dec 2004
    Location
    uk
    Posts
    14,057
    Post Thanks / Like
    Likes (Given)
    4552
    Likes (Received)
    6701

    Default

    Again correct me if im wrong, but this faults really specific to the 737 max, a 747 is a different kettle of fish, its not the anti stall stick pusher, which yes you can over come, its the fact it keeps winding in ever more nose down trim that is the problem, the more it senses the pilot fight it, the more trim it adds every x seconds till the yoke travel is not enough to overcome the trim (trim is greater than stick travel). Whilst throwing enough other alarms + problems the flight crew don't get chance to make sense of it. The whole reason it does this is do to the engine placement and orientation which naturally wants to make the nose come up - stall do to thrust axis every time you add power. Number one stall tactic is add power as well as nose down to recover air speed. Add some failing instruments and it all goes to shit.

    The whole fault ends up becoming a positive feed back loop if not diagnosed till its too late - irrecoverable.

    The fact that china has grounded its 737 maxs kinda says something. Because historically they have been one of the last countries to ground things!

    This is the best explanation by a current 777 pilot i know, of the previous ones data - problem.

    YouTube

  5. #24
    Join Date
    Jan 2017
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    2,543
    Post Thanks / Like
    Likes (Given)
    452
    Likes (Received)
    1810

    Default

    Quote Originally Posted by Tyrone Shoelaces View Post
    ...There must be something drastically wrong with the flight control systems when two nearly brand new aircraft being flown by experienced air crews dive straight in the sea/earth shortly after take off.
    You are really jumping to conclusions here. We're talking about a flight control system that has logged millions of flight hours and hundreds of thousands of TO&L's.

    We don't know the cause of the Ethiopian crash and shouldn't speculate. But we do know that the Lion Air crash was due to the faulty AOA vane, and the plane should have been grounded. The airline operated the jet knowing they had an IAS and AOA MISMATCH. It was the 5th flight of the plane in that condition that crashed.

  6. #25
    Join Date
    Mar 2011
    Location
    Denver, CO USA
    Posts
    10,215
    Post Thanks / Like
    Likes (Given)
    58
    Likes (Received)
    5696

    Default

    Quote Originally Posted by jancollc View Post
    No, it's not that way. The planes are not aerodynamically unstable, and the pilots can overcome the stick pusher by brute force.

    Some military jets are aerodynamically unstable- an F-16 for example. Without the FBW, the jet will swap ends in flight. Commercial and civilian aircraft are not designed that way, they don't need that level of maneuverability.

    What happens in this kind of incident is the pilots suffer from information overload. They just don't have the time to assess everything that's happening.
    The B2 is like that.
    That said, modern planes are flown through software.
    There are no cables running the control surfaces.
    Every movement of the system is run through a computer first.
    The MAX has an auto trim...because setting the trim dynamically in flight would be damn near impossible for the flight crew while also flying the plane.
    Same with every system.
    Managing the engine systems while flying? Let the computer do it.
    Even if you hit manual you are just telling the computer what to do.

    Not to say that mechanics and dumb systems don’t have problems, the rudder reverse issue on the 737 for instance.

    Complex systems have emergent problems.
    Tight performance envelopes become unstable.
    Think of a highly tuned servo being sent out side of its band.
    Add in the erratic inputs of a human operator.

    It’s the nature of the beast.

  7. #26
    Join Date
    Mar 2014
    Location
    Michigan
    Posts
    756
    Post Thanks / Like
    Likes (Given)
    124
    Likes (Received)
    270

    Default

    A Boeing 737-900 engine caught fire on a flight from New Jersey to Houston last night.

    A bang and 'a flash of light' as United jet catches fire en route to Houston

  8. #27
    Join Date
    Dec 2004
    Location
    uk
    Posts
    14,057
    Post Thanks / Like
    Likes (Given)
    4552
    Likes (Received)
    6701

    Default

    Quote Originally Posted by jancollc View Post
    You are really jumping to conclusions here. We're talking about a flight control system that has logged millions of flight hours and hundreds of thousands of TO&L's.
    No this is about the 737 max, not any other model, theres only been 300 odd delivered, they only started flying this model in 2017 commercially, this does not apply to older aircraft - non max versions. Thats if its the same fault as before. The max is significantly different - a pretty big redesign!

    Currently all we do know is the flight radar profile is similar and thats about it, but its a very strange - specific flight profile of multiple climbs and dives despite the aircraft still gaining air speed and what should have been a stable portion of the flight steadily gaining height was akin to a roller coaster. With ever increaseing air speed it shows the engines and rest of the plane was clearly pretty dang functional, the rate of climb and lack of gain in altitude is the real question. Admittedly the radar data only covers about half the flight. But the previous time this happened that radar data was scary similar.

    The flight data recorders have been found so we presumably will have some answers pretty fast if it is the same fault.

  9. #28
    Join Date
    Jan 2017
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    2,543
    Post Thanks / Like
    Likes (Given)
    452
    Likes (Received)
    1810

    Default

    Quote Originally Posted by adama View Post
    No this is about the 737 max, not any other model, theres only been 300 odd delivered, they only started flying this model in 2017 commercially, this does not apply to older aircraft - non max versions.
    Negative. The flight control system on all 737NG and MAX is the same. There are over 7000 737's flying with this flight control system.

    The MAX is a re-engined 737NG with some minor modifications to the wings and airframe.

  10. #29
    Join Date
    Sep 2007
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    5,173
    Post Thanks / Like
    Likes (Given)
    187
    Likes (Received)
    1534

    Default

    Quote Originally Posted by jancollc View Post
    Negative. The flight control system on all 737NG and MAX is the same. There are over 7000 737's flying with this flight control system.

    The MAX is a re-engined 737NG with some minor modifications to the wings and airframe.
    Negative to your negative, I think . MCAS is unique to the MAX 737's, owing to the installation of the LEAP-1B engine, which required changes to engine mounting location, which resulted in aerodynamic changes.

    Regards.

    Mike

  11. Likes cyanidekid liked this post
  12. #30
    Join Date
    Jan 2017
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    2,543
    Post Thanks / Like
    Likes (Given)
    452
    Likes (Received)
    1810

    Default

    Quote Originally Posted by Miguels244 View Post
    The B2 is like that.
    Good grief, a 737 is not a B2.

    Quote Originally Posted by Miguels244 View Post
    That said, modern planes are flown through software.
    There are no cables running the control surfaces.
    All jetliners use hydraulics or jackscrews to move the control surfaces. Of course they use software- that doesn't mean the planes can't be flown manually. The flight control computers are triple redundant- if one mismatches, it's ignored.

    Quote Originally Posted by Miguels244 View Post
    The MAX has an auto trim...because setting the trim dynamically in flight would be damn near impossible for the flight crew while also flying the plane.
    Nonsense. The MCAS does not even turn on until the AOA exceeds a preset limit. It is strictly an augmentation system for manual flight. The jet can be manually trimmed by the pilots just fine without it.

    You REALLY have no idea how easy these are to fly. If MCAS was essential for manual flight, there would be no DISABLE switch. If the jet was as hard to fly as you are imagining, it couldn't even take off.

  13. #31
    Join Date
    Dec 2004
    Location
    uk
    Posts
    14,057
    Post Thanks / Like
    Likes (Given)
    4552
    Likes (Received)
    6701

    Default

    ^ Yes but the system of the nose down trim application is only on the later max ones. This was a near brand spanking new plane that was only delivered in November!

    That said there is now a bit on one of the news feeds saying locals saw it trailing smoke and debris + makeing bad noises prior to the crash. So here is to hoping it is down to something other than the new trim system and really was not caused by that.

    But when you have over 1/3rd of that specific model grounded by its operators over the fear of similarity between a previous accident, you gotta ask the question and i don't think its unreasonable to assume the same at this point till proven other wise is it?

    Again 2 of the same new model of air craft crashing in similar fashion in such a short time span is a significant event. All the more so when the patch to the first crash has still not been rolled out yet. Again, china grounding its 90 planes is pretty dang significant, considering upto a few years ago they were pretty lax about this kinda stuff.

  14. #32
    Join Date
    Dec 2004
    Location
    uk
    Posts
    14,057
    Post Thanks / Like
    Likes (Given)
    4552
    Likes (Received)
    6701

    Default

    Quote Originally Posted by jancollc View Post
    The flight control computers are triple redundant- if one mismatches, it's ignored.

    Yeah but theres still more than a few examples out there of all 3 failing. When your having a truly bad day and some one wants you dead its surprising how much can go wrong at the same time!

  15. #33
    Join Date
    Mar 2011
    Location
    Denver, CO USA
    Posts
    10,215
    Post Thanks / Like
    Likes (Given)
    58
    Likes (Received)
    5696

    Default

    Quote Originally Posted by jancollc View Post
    Good grief, a 737 is not a B2.

    All jetliners use hydraulics to move the control surfaces. Of course they use software- that doesn't mean the planes can't be flown manually. The flight control computers are triple redundant- if one mismatches, it's ignored.

    Nonsense. The MCAS does not even turn on until the AOA exceeds a preset limit. It is strictly an augmentation system for manual flight. The jet can be manually trimmed by the pilots just fine without it.

    You REALLY have no idea how easy these are to fly. If MCAS was essential for manual flight, there would be no DISABLE switch. If the jet was as hard to fly as you are imagining, it couldn't even take off.
    Turn off all the computers...then try to take off.
    Fly-by-wire - Wikipedia

  16. #34
    Join Date
    Jun 2015
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    422
    Post Thanks / Like
    Likes (Given)
    87
    Likes (Received)
    101

    Default

    Quote Originally Posted by jancollc View Post
    If MCAS was essential for manual flight, there would be no DISABLE switch. If the jet was as hard to fly as you are imagining, it couldn't even take off.
    I don't believe there is a disable switch. My understanding is Boeing made an app to compensate for the new engines changing how the plane handles. This app was supposed to be invisible to pilots. They were not trained on it because it was invisible. When things go wrong, it's not clear the pilots knew they were fighting the app and did not know how to disable it.

  17. #35
    Join Date
    Jan 2017
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    2,543
    Post Thanks / Like
    Likes (Given)
    452
    Likes (Received)
    1810

    Default

    Quote Originally Posted by adama View Post
    Again correct me if im wrong, but this faults really specific to the 737 max, a 747 is a different kettle of fish, its not the anti stall stick pusher, which yes you can over come, its the fact it keeps winding in ever more nose down trim that is the problem, the more it senses the pilot fight it, the more trim it adds every x seconds till the yoke travel is not enough to overcome the trim (trim is greater than stick travel).
    The MCAS is new to the 737 MAX, but it does not work as you are imagining. A manual trim adjustment on the trim wheel kicks MCAS out. The disable switch kicks it out. It doesn't even engage until the AOA is too high.

    The FIRST thing in the chain of events is the faulty AOA reading- the MCAS would not normally even be operating- IOW, it would be ON but not necessarily providing trim corrections.

    It's possible that the combination of the stick pusher and MCAS is too much for the pilot to overcome- but that's pure speculation, and the MCAS is easily disabled if that's the case.

    Also, the trim state has no effect on the control column travel.

    Quote Originally Posted by adama View Post
    Number one stall tactic is add power as well as nose down to recover air speed. Add some failing instruments and it all goes to shit.
    On a departure stall you are already at full power. The recovery is just lower the nose. On an approach stall you are at flight idle, so you add power and lower the nose.

    Quote Originally Posted by adama View Post
    The fact that china has grounded its 737 maxs kinda says something. Because historically they have been one of the last countries to ground things!
    China isn't the only one to ground their fleet, and it's the right thing to do until the causes are determined.

  18. #36
    Join Date
    Jan 2017
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    2,543
    Post Thanks / Like
    Likes (Given)
    452
    Likes (Received)
    1810

    Default

    Quote Originally Posted by Finegrain View Post
    Negative to your negative, I think . MCAS is unique to the MAX 737's, owing to the installation of the LEAP-1B engine, which required changes to engine mounting location, which resulted in aerodynamic changes.

    Regards.

    Mike
    Yes, I noted the addition of the MCAS. But the actual flight control system is the same one as the NG. The MCAS is an add-on, not part of the stall warning system which is activated by inputs from the pitot static and AOA sensors.

  19. #37
    Join Date
    Jan 2017
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    2,543
    Post Thanks / Like
    Likes (Given)
    452
    Likes (Received)
    1810

    Default

    Quote Originally Posted by CosmosK View Post
    I don't believe there is a disable switch. My understanding is Boeing made an app to compensate for the new engines changing how the plane handles. This app was supposed to be invisible to pilots. They were not trained on it because it was invisible. When things go wrong, it's not clear the pilots knew they were fighting the app and did not know how to disable it.
    That's not accurate. Yes, the system is automatic, but there has always been a cutout switch. The decision was made to not include it in the training by some airlines, because it's supposed to be invisible to the pilots.

    If you read the TSB from Boeing, they specifically say to disable the auto stab trim and leave it off for the duration of the flight.

    See pic.
    737-max-trim-control.jpg

  20. Likes adama liked this post
  21. #38
    Join Date
    Dec 2004
    Location
    uk
    Posts
    14,057
    Post Thanks / Like
    Likes (Given)
    4552
    Likes (Received)
    6701

    Default

    Quote Originally Posted by jancollc View Post
    Also, the trim state has no effect on the control column travel.
    Yes you can move the stick just as much, but my understanding was at the full trim stick fully back was not enough to then take the plane back to level flight based on the previous accident report? The pilots in that one had done multiple trim "reductions" but the auto system then just reapplied it and more mere seconds later, add in the cockpit confusion from one pilots angle of attack showing 20 degree's different to the others.

    If the local report about it already trailing derbies and smoke and such then its more than plausible this is going to be down to something else. But based on the crater i feel really sorry for who ever has to try and find any real component failure items.

    Like it or not but as humans were rapidly now approaching the point were automated system fails are probaly going to become a bigger killer than ever before. Its going to become a hard pill for people to swallow knowing after the event some simple differences in code and such could have prevented the accident and the real world reduction in human errors won't do much to make people any more will to accept being killed by a machine not a human. Even if the machine is only tiny fractions of a percent as likely to kill you.

    You only have to look at the self driving cars to see this, for miles traveled there way safer, but every single bump sees them dragged across the coals.

  22. #39
    Join Date
    Jan 2017
    Country
    UNITED STATES
    State/Province
    Oregon
    Posts
    2,543
    Post Thanks / Like
    Likes (Given)
    452
    Likes (Received)
    1810

    Default

    Quote Originally Posted by Miguels244 View Post
    Turn off all the computers...then try to take off.
    Fly-by-wire - Wikipedia
    So what? Disable the ECM in your car and try to drive away...

    Do you understand what "manual flight" means?

  23. #40
    Join Date
    Jun 2015
    Country
    UNITED STATES
    State/Province
    Texas
    Posts
    422
    Post Thanks / Like
    Likes (Given)
    87
    Likes (Received)
    101

    Default

    Quote Originally Posted by jancollc View Post
    That's not accurate. Yes, the system is automatic, but there has always been a cutout switch. The decision was made to not include it in the training by some airlines, because it's supposed to be invisible to the pilots.

    If you read the TSB from Boeing, they specifically say to disable the auto stab trim and leave it off for the duration of the flight.
    I'm not sure what you say is accurate either. That disable doesn't disable MCAS. From what I've read on the pilot chat area, MCAS will kick back in shortly. Plus cranking a handwheel while the Z axis is full rapid towards the table may be not enough. I'm not a pilot, so I won't comment further. Seems to be the plane needs to be grounded until it's fixed and pilots are trained. Boeing did a lot of hand waving after Lion Air and got off without a grounding and no fix implemented.


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •