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Thread: OT: not about 737MAX, but yeah, it kinda IS about that.

  1. #1
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    Default OT: not about 737MAX, but yeah, it kinda IS about that.

    This article as linked... apparently it is NOT just 737MAX that have had similar issues, and not only recently:

    https://avherald.com/h?article=47d74074
    1601

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    Hashim Khan

  2. #2
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    I've been following a very long ongoing discussion on airliners.net, about the recent 737MAX incidents. More than 3800 posts in the thread so far!

    http://www.airliners.net/forum/viewt...519&start=3800

    The full report on the most recent Ethiopian Air incident is expected very soon. Some other articles:

    https://www.zerohedge.com/news/2019-...tware-engineer

    https://www.straitstimes.com/asia/se...to-last-flight

    Here is an incredible video showing a similar aircraft entering a stall and being recovered, but it seems to require a nose down and steep dive to pick up speed before pulling up and leveling out. Not too hard when instruments and controls are working, and you have enough altitude to dive a few thousand feet without impacting terrain.


  3. #3
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    Quote Originally Posted by PStechPaul View Post
    Here is an incredible video showing a similar aircraft entering a stall and being recovered, but it seems to require a nose down and steep dive to pick up speed before pulling up and leveling out. Not too hard when instruments and controls are working, and you have enough altitude to dive a few thousand feet without impacting terrain.
    That steep dive that you mention is not quite as it appears. A stall is when the plane loses lift and literally starts to fall out of the sky. The nose down lets you get air flowing over the wings again (proper angle of attack) and the speed is necessary to generate lift. Once you have sufficient lift you are flying again and can pull up.

    But you are right, a low altitude stall can be quite deadly. That's why stall alarms and stall indicators are required in all planes.
    At the end of the project, there is a profound difference between spare parts and extra parts.

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    Nose down IS THE stall recovery technique.... A stall is excess angle of attack (wing angle with respect to airflow) and is associated with slow speed relative to the air density at your altitude. A "low energy" position. As you go slower, you need increased angle of attack, or else flaps.

    So, nose down means increasing speed, and increasing energy, as well as a decreasing angle of attack.

    The MCAS automatically trimmed the nose down, which seems to be the issue in the crashes... it did not need to because there was no stall, the sensor, which is known to be a possible issue (see link), was giving bad data.

    But, there was a switch to shut down the system, and that switch was apparently not used.

    https://www.bloomberg.com/amp/news/a...-later-crashed
    Last edited by J Tiers; 04-02-2019 at 02:39 AM.
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    They didn't have much time to react - see this simulation: https://www.youtube.com/watch?v=l-tmcQebeN8

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    Quote Originally Posted by danlb View Post
    That's why stall alarms and stall indicators are required in all planes.
    Just a slight correction. While that is true for some classes of aircraft operating under some sets of FAA regulations, it is not true for all aircraft. There are 10s of thousands of aircraft that operate safely without a stall warning system (including mine).


    A comment on a different post about the autopilot disconnect. In my opinion, the ability and knowledge to disable an autopilot is critical. I have that same kill switch and have had to use it when the autopilot did not do what it was supposed to. (Predominantly because of a programming button pushing error by me). One must be able to kill the autopilot quickly and simply. Disconnection and hand flying is the safe alternative in many cases.
    Last edited by rzbill; 04-02-2019 at 12:36 PM.
    Bill Pendergrass
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    It's happened to other Airbuses as well: https://en.wikipedia.org/wiki/Qantas_Flight_72

    Level flight, the avionics decided that the plane suddenly had an angle of attack of 50 degrees, and quite naturally put the plane into a dive to "recover". How? The software relabeled altitude data as AoA data. Happened on other flights as well.

    There's lots of criticism of Boeing flying around, but didn't I read that the copilot, Ahmed Nur Mohammod, had 200 hours of total flying time? He also hadn't been on the 737 MAX simulator. I'm sure it all goes fine when everything's normal, but would someone with this level of experience be an effective crew member in an emergency situation?

    As JT mentions, there's a switch to disable MCAS (as there is for most systems on airliners), and the switch wasn't used...

    Ian
    All of the gear, no idea...

  8. #8
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    The combination of a low time pilot and a possibly faulty system can prove deadly.
    I hope the fix for the system is easy. The fix for the pilot is easy. Just demand more hours.
    The FAA raised the minimum to 1500 hours for an ATP rating in the USA after a crash involving two low time pilots here.
    My grandson is a flight instructor here in Florida building hours so he can get a job with the airlines.
    He has accumulated 1350 hours in the last 2 years of instructing mostly foreign students. He says they get 2-300 hours and then go home and fly for their countries airlines well before they should in his opinion.

    The general aviation segment is not immune from this sort of accident.
    We fly a CitationJet in our company. There is a third party company (not Cessna) that has developed a set of variable incidence computer controlled winglets for the CitationJets. We were looking at them for our airplane because they increase the climb rate and cruse speed.
    A very qualified pilot that had flown our aircraft on on a trip for us a few days before crashed killing all aboard in the CitationJet he flew regularly that had those winglets. There have been more than one incidence of loss of control because of a computer failure in that system.
    The NTSB report has not been issued but the winglet system is under suspicion.
    Needless to say we have stopped looking at that system.
    Bill
    I cut it off twice and it's still too short!

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    There's a lot of discussion lately of pilots on modern large aircraft relying on automation, becoming complacent, and losing the ability to fly the aircraft. The, when something like a bad sensor provides erroneous data, there's precious little time to sort it out.

  10. #10
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    Quote Originally Posted by danlb View Post
    That's why stall alarms and stall indicators are required in all planes.
    That would be quite annoying in an an Extra 300....

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