737 grounded???

Discussion in 'Hangar Flying' started by Aerowerx, Mar 13, 2019.

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  1. Apr 7, 2019 #61

    DangerZone

    DangerZone

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    It seems the media is trying to pin that imidge to Boeing, but in reality Boeing has some better design choices than Airbus. Feel free to watch the following video to see what it's like when Airbus computers go berzerk. Luckily, the pilot was an experienced ex-US Navy pilot who managed to save the lives of everyone on board.

     
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  2. Apr 7, 2019 #62

    Jerry Lytle

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    As a follow-on to Danger Zone's comment on Airbus's flying by wire problems I would submit:American Airlines Flight 587 November 12, 2001, According to the NTSB, the aggressive use of the rudder controls by the co-pilot caused the vertical stabilizer to snap off the plane, along with the plane's two engines separating from intense forces before impact.
    At the time I questioned the ability of a human's physical force on rudder pedals would have enough energy to sever the tail and both engines from the plane. Likely a human pilot couldn't, but the fly-by-wire system had no similar energy limitation.
    Can fly-by-wire still kick the tail off an Aibus 330?
     
  3. Apr 8, 2019 #63

    lr27

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    If memory serves, the problem was that he went back and forth on the rudder a few times. It wasn't just one big stomp that did it. Don't most jetliner's controls have hydraulics? I imagine it's very possible to program a fly by wire system NOT to break off the rudder by restricting the travel when yaw rate and air speed were above certain values together.
     
  4. Apr 8, 2019 #64

    TFF

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    It probably does have a rudder limiter. If the program gets compromised, it’s all up in the air. When I worked for a regional, we had a plane take off and when the autopilot was engaged, it tried to fly straight down. It would not disengage. The captain was a small woman and she could not hold it against the elevator servo. The FO was this big dude who held the pressure off so she could fly it. It would have made the news. She was pissed when she got off the plane. She was never pissed. Cause? Someone checked their email on a secure computer that programmed the flight control computer boards. Grounded about 100 airplanes across the US. The emergency AD was so fast that it was cleared before they could put it in print. The avionics company programmed day and night for a week to get everyone going. I think we had 15 planes that had to be dealt with. People are not foolproof and neither is anything people make. We get darn goood but nothing is 100% ever.
     
  5. Apr 8, 2019 #65

    pictsidhe

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    I'm no expert pilot, but I'm starting suspect that knowing how to deal with malfunctions of the ever increasing automation may be stretching many pilots too far. It seems that there are an increasing number of accidents where the pilot forgot an obscure procedure in the phone book sized manual. Top notch pilots often fly out of these situations, but the ones who scraped through and tend to get the jobs in lest prestigious airlines, less often. Considering that there is something of a pilot shortage, raising the bar further isn't going to fix the situation.
     
  6. Apr 8, 2019 #66

    davidb

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    Yes, rudders are typically hydraulic and are limited by phase of flight. Rapid full reversals of rudder causes some immense forces that are well beyond certification criteria. Current upset recovery training emphasizes not using the rudder so as to avoid the possibility of breaking off vertical stabilizers and engines.
     
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  7. Apr 8, 2019 #67

    Vigilant1

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    I don't know about an A330, but it seems very unlikely that a fly-by-wire rudder control system caused the crash of AA Flight 587. It was an A300-600, and there is no true fly-by-wire control of the ruder in the A300-600.

    There's a description and drawing of the A300's rudder system on Pg 19 of the pdf here:https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR0404.pdf

    The rudder controls are unpowered/unaugmented pushrods, bellcranks, and cables from the foot pedals to the rudder. There's an electrohydraulic yaw damper and there's the standard electric trim, but neither has the rate of movement needed to exert the forces that snapped that fin off. But a pilot dancing hard on the rudder pedals, back and forth, could do it. Pages 28-29 provide a clue to the possible problem: at 250 knots, every pound of pressure applied to the rudder pedals in an A300-600 produced a lot of rudder travel: about 4-8 times as much rudder displacement as the same amount of foot pressure would have produced on Boeing and McD-D airliners.
     
    Last edited: Apr 8, 2019
  8. Apr 8, 2019 #68

    BJC

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    You have a legitimate concern.

    Another is the scope and effectiveness of the training. Do pilot’s today learn what they need to know about actually flying an airplane rather than operating systems? Remember the rule, “First, fly the airplane”? That (perceived, by me) training deficiency applies to Private pilots as well as Airline Transport pilot’s.


    BJC
     
  9. Apr 8, 2019 #69

    TXFlyGuy

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    The major US carriers, especially the legacy airlines (AMR / DAL / UAL), all emphasize hand flying the airplane during training. While going for my 777 type rating, one sim session was devoted entirely to hand flying the airplane. No autopilot, no auto throttles. We were allowed the use of the flight director, however.

    This was the most difficult sim ride of the entire syllabus. Not because we could not hand fly, but simply because the big jets from Boeing / Airbus are designed to be operated using the A/P.

    The workload environment in today's ATC system, especially on departure from busy airports like EWR, plus some airports in Europe, pretty much require the use of the A/P.

    On a busy / complex SID, the monitoring pilot can become overloaded...setting altitudes, headings, airspeeds, plus answering all of the radio calls. Having the flying pilot use the A/P greatly decreases workload, and enhances safety by a huge margin.

    The same thing can be said about STAR's. It can get very busy. It takes two pilots to safely fly the airplane. In my case, with single or double augmented crews, I have seen times when having that 3rd or 4th pilot on the flight deck was a huge help.

    Certainly, hand flying has a place. But there are many times when simply using the A/P is the wiser and safer choice.

    Just my nickels worth...
     
  10. Apr 8, 2019 #70

    BJC

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    Sorry, I wasn't clear. I wasn't referring to hand flying, or even flying transport aircraft. I was referring having experience flying at all the edges of the flight envelope, recovering from unusual attitudes, becoming proficient in spins, slips, stalls, etc.


    BJC
     
  11. Apr 8, 2019 #71

    gtae07

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    Is it just "manual flying skills" themselves that are deficient? Or is it also insufficient training and conditioning in breaking out of "target fixation"--that is, getting pilots used to recognizing when they're getting swamped and realizing it's time to click off George and take over?
     
  12. Apr 8, 2019 #72

    Vigilant1

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    The ironic part is that, when the 737 MAX autopilot is engaged, the MCAS routine is inactive. From what has been released so far about these crashes, neither would have accurred if "George" was flying. That's not to say that crewmembers don't need to know how to hand fly the aircraft.
    These >particular< crashes, from what has been released, to me indicate that systems knowledge, knowledge and ability to implement the memory procedures, and an understanding of the rationale behind the published procedures is important. Boeing didn't help by not publicizing the existence of the MCAS, but prompt application of the existing procedures and the ability/willingness to hand-fly the plane (to include use of the manual trim wheel in place of electric trim) would apparently have seen these incidents through to a different ending.
     
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  13. Apr 8, 2019 #73

    BJC

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    I was not referring to hand flying. I’m referring to the skill set that should have let the crew of Air France flight 447 recognize, and safely recover from, their stall. I’m referring to the skill set that would enable a flight crew to recognize that a trim system or a stick shaker is not operating properly. I’m assuming that if they recognize that, they will know what to do.


    BJC
     
  14. Apr 9, 2019 #74

    TXFlyGuy

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    In the case of AF447, all of the hand flying skills in the world would not have saved these two pilots. They simply failed to correctly interpret the data that was presented to them. The info was right there, if they would have looked at it. Yes, it would have been a challenge, but not for someone who knew what to look for. Pitch and power. Not to over simplify, but that would have been a good start, and would have saved their rear ends. Had they just done nothing, they would have been better off.
     
  15. Apr 9, 2019 #75

    BJC

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    I never referred to hand flying skills, except to explain to you and ‘07 that I had not referred to hand flying.

    Yes, they “simply failed ...”. That illustrates my point.


    BJC
     
  16. Apr 9, 2019 #76

    TXFlyGuy

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    I guess I misunderstood.

    When it comes to hand flying an airliner, it is normal for me to hand fly up to FL180 on departure, if it is not a super busy ATC environment, and if the departure SID is not extremely complicated.

    On arrival, I always leave the A/P on until the preceding aircraft is clear of the runway. Just in case we would have to execute a missed approach.
     
  17. Apr 9, 2019 #77

    davidb

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    I’d say that is typical practice for U.S. airline pilots. I wonder what is typical for other countries. The preliminary report indicated the pilots of the latest crash were attempting to engage the autopilot at 400 feet. The minimum engagement altitude is 800 feet and the common action for most control/indicator anomalies is to disengage the autopilot.

    If the standard practice is to engage and rely on automation as soon as possible, it leaves one at a disadvantage when automation isn’t available nor appropriate.
     
  18. Apr 9, 2019 #78

    TXFlyGuy

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    The 777 has a restriction of 200 feel AGL for the A/P to be used on departure. On arrival, it can be used all the way through the flare, and touchdown. This applies to a single engine approach also. The Triple is certified for CAT III single engine autoland.

    With regards to the 737 / MCAS, how many incidents have happened with US carriers that were successfully dealt with by the crew, thus it never made the news?
     
  19. Apr 9, 2019 #79

    BJC

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    I’ve wondered about that. Discussions among ALPA members likely would be the best source of data. What have you airline pilots heard?


    BJC
     
  20. Apr 9, 2019 #80

    davidb

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    AFAIK, there has been no inappropriate stick shaker or MCAS events at U.S. carriers wrt the Max.
     
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