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retread

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Posts posted by retread

  1. Russian hacking skills are 4 years more advanced than the last Presidential election. Like triple posted in another thread, there are also other govts. that also have the ability to hack into voting systems without being detected. It's not unreasonable to think that the Russians would take advantage of those resources as well.

    And we haven't addressed Russian hacking in '16 to any reasonable degree. This is what a foundering country looks like.

  2. 36 minutes ago, WhatTheBuck said:

    Case in point: one of his supporters who parroted his hate speech murdered 22 people in El Paso just two weeks ago. Then Trump staged a photo op with an orphaned baby. 

    I know that we all know this, but it can't be said enough. This sociopath had someone bring the orphaned baby back to the hospital for a photo opp. The same baby who was orphaned in no small part due to the inflammatory, racist, hate-mongering rhetoric of the US President.

    • Like 4
  3. 6 hours ago, Bobby_Batronic said:

    There’s 5500 of them ordered. Airbus couldn’t make up the difference in their wildest dreams. The Max will not only survive, but will be a mainstay in the skies. 

    If you were in charge of fixing/removing MCAS, how would you handle it? Appreciate all the good insights from the pilots itt.

  4. It's amazing. Only on the Cheeto timeline would the media/nation be talking about buying Greenland, as opposed to child-rape rings, impeachment, white supremacist violence, imprisoning children in cages, Saudi Arabia murdering a WaPo journalist, etc. It all just falls by the wayside when he throws new shit on the wall.

    • Like 1
  5. 48 minutes ago, ChiTownDoc said:

    I have seen some otherwise put together acquaintances end up in pics like this - they're drunk 100% of the time. 

    I'd like to point out that President kissy face does not drink. 

    Do you think he's a pill popper? What kind?

  6. Interesting read as to why ET302 was flying so fast, and why the pilot's electronic trim commands were short bursts, as opposed to longer durations.  https://leehamnews.com/2019/04/05/bjorns-corner-et302-crash-report-the-first-analysis/

    Quote

    The insufficient trim mystery after re-activation of Electric Trim
    After 7 PF commands Electric Trim Nose Up in two short cycles. I asked my selves (as did others) why these short trims? They are fighting to get the nose up to the extent they risk switching in the Electric Trim again. Then why not trim nose up continuously or for at least long cycles once Electric Trim is there? It took me several hours to find an explanation. Here my take:

    To understand the blip trims one must have flown fast jets at low altitude. At the speed ET302 is flying, 360kts, it’s hypersensitive to trim. The least trim action and the aircraft reacts violently. Any trimming is in short blips.

    As PF holds the nose up with a very high stick force, now for a long time, he’s sensitivity to release stick with trim is not there (this is what Pilots do when they trim nose up, otherwise the aircraft pitches up fast). He trims therefore in short blips and has difficulty to judge the trim effect he has achieved. His is not flying on feel. He can’t, he is severely out of trim, holding on to the Yoke with a strong pull force.

    Anyone who has flown a grossly out of trim aircraft at high speeds knows your feel is compromised. The sensors you have to rely on are your eyes, not your hands.

    PF has the horizon glued to read the aircraft. The result is the short nose-up trims we see. The nose goes up and the stick force needed is reduced. His judgment is; this is enough for now, it was a powerful response. Any MCAS attack I now trim against, then I correct my trim if I need to.

    But the aggressive MCAS, trimming with a speed 50% higher than the pilot and for a full nine seconds, kicks in at 8 with a force they didn’t expect. Speed is now at 375kts and MCAS was never designed to trim at these Speed/Altitude combinations. Dynamic pressures, which governs how the aircraft reacts to control surface movements, is now almost double it was when last MCAS trimmed (Dynamic pressure increases with Speed squared).

    Quote

    The throttles are left at 94% thrust for the whole flight. This is higher than normal but this is a high takeoff. At 7,600ft it is a full 2,200ft higher than Denver, which is the US Benchmark for high takeoffs. And with Stick Shaker and IAS disagree you keep high thrust and fly a slow climb (the IAS disagree is present in the traces but not mentioned in the report specifically. We don’t have all the Crew callouts and discussions present in the report is my conclusion).

     

  7. Boeing personnel were authorized to work on behalf of the FAA. Tasks were divided up. As the MCAS was tweaked on simulators, the engineers adjusted the maximum rotation of the stabilizer. Most engineers thought it was 0.6 degrees. Turns out, MCAS had been set up to be able to move the stabilizer 2.5 degrees each time. It was also authorized to actuate multiple times.

    That info was not included in the System Safety Analysis submitted for the MAX's final approval. IIRC, it's supposed to include everything that is changed.

    "After the Lion Air Flight 610 crash, Boeing for the first time provided to airlines details about MCAS. Boeing’s bulletin to the airlines stated that the limit of MCAS’s command was 2.5 degrees.

    That number was new to FAA engineers who had seen 0.6 degrees in the safety assessment.

    The FAA believed the airplane was designed to the 0.6 limit, and that’s what the foreign regulatory authorities thought, too,” said an FAA engineer. “It makes a difference in your assessment of the hazard involved.”

    Quote

    The safety analysis:

    Understated the power of the new flight control system, which was designed to swivel the horizontal tail to push the nose of the plane down to avert a stall. When the planes later entered service, MCAS was capable of moving the tail more than four times farther than was stated in the initial safety analysis document.

    Failed to account for how the system could reset itself each time a pilot responded, thereby missing the potential impact of the system repeatedly pushing the airplane’s nose downward.

    Assessed a failure of the system as one level below “catastrophic.” But even that “hazardous” danger level should have precluded activation of the system based on input from a single sensor — and yet that’s how it was designed.

    After the Lion Air Flight 610 crash, Boeing for the first time provided to airlines details about MCAS. Boeing’s bulletin to the airlines stated that the limit of MCAS’s command was 2.5 degrees.

    That number was new to FAA engineers who had seen 0.6 degrees in the safety assessment.

    “The FAA believed the airplane was designed to the 0.6 limit, and that’s what the foreign regulatory authorities thought, too,” said an FAA engineer. “It makes a difference in your assessment of the hazard involved.”

     

     

    The higher limit meant that each time MCAS was triggered, it caused a much greater movement of the tail than was specified in that original safety analysis document.

    The former FAA safety engineer who worked on the MAX certification, and a former Boeing flight controls engineer who worked on the MAX as an authorized representative of the FAA, both said that such safety analyses are required to be updated to reflect the most accurate aircraft information following flight tests.

    “The numbers should match whatever design was tested and fielded,” said the former FAA engineer.

    But both said that sometimes agreements were made to update documents only at some later date.

    https://www.seattletimes.com/business/boeing-aerospace/failed-certification-faa-missed-safety-issues-in-the-737-max-system-implicated-in-the-lion-air-crash/

  8. Lion Air pilot did pretty well fighting MCAS with the electronic thumb switch. IIRC, MCAS rotates the stabilizer at a greater rate than the pilot's thumb switch, but I'm not sure. So, if he kept hitting that switch, could he have kept the plane in the air? FDR looks like it was a losing battle.

    The pilot handed controls off to the first officer toward the end.

    Quote

    The sources told Reuters that the pilots remained calm for most of the flight. Near the end, the captain asked the first officer to fly while he checked the manual. 

    tNvjGw.jpg

  9. 3 minutes ago, C-Man said:

    It's been a long time since we went over this but I think the contributing factor to the stabilizer being "locked" was that they were going too fast to turn the dial manually.

    Not excusing any of this, BTW. Just trying to remember some of the specifics.

    Yep.^ Forces acting on the stabilizer (internal jackscrew) at higher speeds make it harder to turn the manual trim wheel. If you don't catch it early, you're in trouble.

  10. 45 minutes ago, bschoolprof said:

    So my layman understanding is that they cut the switches to prevent the MCAS nose down inputs (which is what was talked about a ton on this thread), but the stabilizer was still trimmed to a nose down position (presumably because it just stayed where it was) and the manual trim adjustments weren't working, perhaps in part because the plane was going too fast.  So they turned the automated trim system back on, MCAS took over, and then they crashed.  What should they have done? Slowed down? 

    The pilots can correct me if I'm off, but I think turning the stab trim cut-out switches off early enough is the key. If you don't, the factors you list play against you.

    I think Lion Air tried to use the thumb switch on the yoke (electric trim adjust) more than the Ethiopian flight. Still, they didn't turn of the stab trim switches soon enough. MCAS' actions were more influential than the thumb switch used by the pilot.

    Lion Air FDR https://static.seattletimes.com/wp-content/uploads/2018/11/LionAir-BlackBox-WEB-1560x1040.jpg

  11. I would love to see the Ds effectively run w GoLL's post re: taxes/trickle down. No more tax cuts for the rich. We've tried that and it didn't work. The Rs have been lying to you for 3 decades, etc.

    I'm sure some/most Ds have that as their platform, but I'm talking about effectively pounding that message for the next 15 months.

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