Comments by "GH1618" (@GH-oi2jf) on "Plainly Difficult" channel.

  1. Overall, a good summary of the history of B737 development, but the discussion of the relationship of engine placement to the problem is not accurate. All jet aircraft with engines mounted under the wings experience a pitch-up moment under power, simply because the engine axis lies below the center of mass. This is entirely normal and it is compensated for by adjustment of the horizontal stabilizer, called “trim.” The problem the MAX designers faced was simply that the more powerful engines of the MAX required more trim during takeoff than the previous models, giving the aircraft somewhat different handling. The difference was enough that a new type certification would have been required of pilots. The MCAS automated the application of increased trim during takeoff, which allowed it to be flown with the same type certification as for the NG-series. Sadly, the implementation was botched and there certainly was a shameful attempt by Boeing to avoid responsibility. The issue has been discussed by professional pilots who have YouTube channels, notably Blancolirio and Mentour.
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  2. The B737s have always had two sensors. The problem was in how they were used in the MAX, acting on the data when the two sensors disagreed. Previous versions of the 737 did not take any action which would imperil the plane as a result of bad sensor data. Ironically, the problem was caused by a break from traditional Boeing philosophy, which holds that the pilot has ultimate control of the aircraft.
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  3.  @regaubade8329  — No, there are no bridges like it in Ottawa or anyhere else. It was unique.
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  4.  @crono331  — Certainly the pilots (and the FAA) should have been told about the system, but more importantly they should not have done such a half-baked implementation. We still haven’t been told how this came about and we probably will never know.
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  5. I wouldn't do such things in the USA, either. We have our share of fatalities associated with such things.
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  6. There was no bridge like this one anywhere in the world.
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  7. ABC was not at fault, though.
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  8. To get to the other side.
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  9. The Engineer of Record was Denney Pate (male). Flores was an executive at MCM, the construction company that built the bridge, but she was not involved in this project.
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  10. It is a large intersection on busy road, and whatever measures are taken, you cannot prevent accidents cause by drivers who are inattentive, reckless, or drunk. Pedestrian overpasses are not unusual remedies, but most are built far better than this one and at lower cost.
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  11. No. That has been refuted many times. The reports from OSHA and NTSB are public. Read them.
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  12. Where did you get that? Denney Pate P.E. was engineer of record for the bridge.
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  13. Are you being sarcastic?
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  14. The Engineer of Record was male.
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  15. Not exactly. The bridge engineering company was run by a woman, I think, but the Engineer of Record was male. There were many people of both sexes involved in this fiasco.
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  16. By the way, Accelerated Bridge Construction was not the problem. The design was.
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  17. psikeyhackr — The WTC buildings are completely understood. The analysis is available in a NIST report. WTC conspiracy nuts disgust me. They dishonor the dead by exploiting the tragedy to promote their cockamamie fantasies.
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  18. What you call an “aerodynamic problem” really wasn’t one. It was just a small change in behavior which had economic consequences. The plane could be flown perfectly well without MCAS, but FAA rules would have required separate type certification for pilots, which has a cost. Boeing did neglect to tell anyone about it and, what’s worse, they botched the implementation. Those were problems and, to compound the problem, they tried to claim the crashes weren’t their fault, even when everyone (including Boeing) knew they were. That doesn’t mean it was malice — that’s a subject for lawyers.
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  19. If you want a suspension bridge, or a cable stayed bridge, you have to start with that concept and build it accordingly. In this case, they rejected a cable-stayed design because they wanted to erect the span with minimal road closure time required. They put the “decoration” on because they liked the look of a cable stayed bridge, but that is not what caused the collapse. It collapsed because they built an extraordinarily heavy truss out of inappropriate materials, and poorly designed, which was not strong enough to hold itself up. Adding a few more supports could not save a fundamentally unsound concept.
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  20. The initial mistake was to build a two-lane bridge, apart from the flexibility issues. It did not make economic sense.
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  21. This was not about diversity hires. It was about hubris and politics.
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  22. "Coincidence" means only that two events happen at about the same time. There are countless coincidences every day.
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  23.  @ericpeterson9110  — The university was certainly in on the concept, which was fundamentally unsound. They wanted a signature bridge.
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  24. It isn’t true that it hires only women. The Engineer of Record, a FIGG employee, is male.
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  25. Even steel trusses are not fully redundant. A truss bridge in Washington State collapsed a few years ago when a truck with a wide load struck one member.
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  26. He did cover it and he debunked the misinformation that was circulating on the nature of the problem.
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  27. They used tensioning rods to compensate, but that’s much more complicated than just using a better material.
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  28. There were many male engineers involved in this, beginning with the engineering faculty of FIU, who wanted a structure that would make a bold statement. It did.
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  29. Not in this case. Blue def technology works. VW just didn’t want to implement it and compete on an equal footing with other car makers. They pretended their cars didn’t need it by gaming the system. It was outright fraud.
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  30. The NTSB found that the design was inadequate for the load.
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  31. Many people who followed this incident were interested in the engineering aspects more than the political aspects. I am among them. Anyway, it was not “all female.”
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  32. It is not normal to build any truss with concrete. There is only one other in the US that I am aware of.
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  33. Every building and every fire is a unique event. The failure of building Seven was thoroughly documented by NIST, along with the others. Edit: By the way, nobody cares whether you believe it. The NIST reports are for people who want to understand what happened.
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  34. Texas?
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  35. There was before the grounding and rework of MCAS. The problem was that MCAS was fighting the pilot’s intentions and the pilots has no knowledge of the system so had to figure out what to do on the spit, with very little time to do it. There is no question that as originally implemented the plane’s behavior in certain circumstances was fundamentally wrong. That is why the whole world grounded the aircraft and demanded that it be fixed.
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  36. Any high-speed train needs grade separation from other traffic for safety. If it were at ground level, there would be additional cost for fencing. A long route without crossings would be an inconvenience, so you might need expensive underpasses. Elevation also makes it easier to build a level track over uneven ground.
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  37. FIGG engineering and Denney Pate have been barred from federal projects for ten years.
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  38. This was a truss, but a poorly designed one.
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  39. The highway was there before the pedestrians.
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  40. Boeing builds what their customers want. There was considerable input from their largest customers that led them to make a new variant of the 737 rather than an all-new aircraft. Boeing is not the only company motivated by the economics.
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  41. I expect FIU had a great deal to do with the concept, as you suggest. Today, of course, nobody will admit to creating the concept. But even if FIU designed the concept, FIGG is to be faulted for agreeing to design it. The Engineer of Record put his stamp on it. He advised, more than once, that the cracks were not a safety concern. He is responsible.
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  42. They were not only large, they were active.
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  43. This is an engineering history channel, not a news channel.
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  44. Resistance to wind is separate from resistance to gravity. Had it been able to hold itself up, it might have withstood wind easily, because it was heavy and was open so the wind would just blow through.
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  45. Either way, stretching a vehicle as is done for these stretch limos is craziness. This was not the first disaster, and it won't be the last until they are banned. The only legitimate way to make a limo for a large group of passengers is to start with a commercial truck chassis, and use it the way it comes, with a custom limousine body.
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  46. I doubt any board member has ever been held criminally responsible for an airplane crash. That just isn’t going to happen. Which board member and for what violation of law did you have in mind?
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  47. The did get some advice from TY Lin. They ignored it.
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  48. Two executives were fired. Probably not enough.
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  49. They aren’t too big. They just changed the characteristics of the aircraft enough to make the FAA think it was a new type.
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  50. In order to put someone in jail you have to prove a specific criminal act committed by the individual.
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