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I used to instruct in a 172 that had been flipped onto its back by jet blast years earlier. Probably as a result of that, it didn't fly straight, and "coordinated flight" was done with the ball about 1/4 scale deflected to the right. That airplane had a number of other fun quirks (it was a 1969 model, so nothing was located where you'd expect it to be), and I think the flight school eventually sold it when instructors basically refused to fly it.
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Apr 4, 2019 18:28
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Spanish C-295 failed to land.  Experts undecided yet as to whether it'll buff out.
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Apr 4, 2019 19:10
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Looks to me like it landed just fine 
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Apr 4, 2019 19:29
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Cat Mattress posted:Spanish C-295 failed to land. Both props feathered...?
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Apr 4, 2019 19:30
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my kinda ape posted:Looks to me like it landed just fine Yeah, looks like one you can walk away from, so there's that.
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Apr 4, 2019 19:35
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Cat Mattress posted:Spanish C-295 failed to land. RCAF expected to take delivery shortly
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Apr 4, 2019 21:08
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Prelim report on the Ethiopian crash if it wasn't already posted: https://assets.documentcloud.org/documents/5793877/Preliminary-Report-B737-800MAX-Ethiopia.pdf TL;DR Boeing hosed up
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Apr 4, 2019 21:50
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Boeing is in for some pain. Ralph Nader's grandniece was on board the Ethiopian Air flight and he's calling for a complete recall of the MAX jets. Odds of this actually happening?
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Apr 4, 2019 22:00
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dubzee posted:Boeing is in for some pain. Thats effectively what grounding until they can re-manufacture the system is, isn't it? KodiakRS posted:Prelim report on the Ethiopian crash if it wasn't already posted: https://assets.documentcloud.org/documents/5793877/Preliminary-Report-B737-800MAX-Ethiopia.pdf Look at the manual trim commands on page 26 - it just stopped responding.
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Apr 4, 2019 22:05
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dubzee posted:Boeing is in for some pain. Big yikes
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Apr 4, 2019 22:06
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dubzee posted:Boeing is in for some pain. I would say that this is de-facto happening. At this point, the writing is on the wall that the system will have to be reworked before they're allowed to fly again. The real question is if they'll be allowed to keep the same type rating.
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Apr 4, 2019 22:11
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hobbesmaster posted:Thats effectively what grounding until they can re-manufacture the system is, isn't it? Nader is on about the design itself being defective. Adding the larger engines throws off the CG hence the software being needed to keep the thing from stalling. Updating the software doesn't fix a hardware issue. Disclaimer; I don't know poo poo, just going by what he said in the NPR interview.
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Apr 4, 2019 22:20
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hobbesmaster posted:Look at the manual trim commands on page 26 - it just stopped responding.
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Apr 4, 2019 22:24
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Twerk from Home posted:I would say that this is de-facto happening. At this point, the writing is on the wall that the system will have to be reworked before they're allowed to fly again. The real question is if they'll be allowed to keep the same type rating. Generally, a software change won't require a new type rating, but there's no way that a substantial segment on "This is what MCAS does, here's how to disable it" isn't going to be mandated as part of the differences training for the MAX. I'm guessing the biggest change to come out of this whole mess is a substantial overhaul of the FAA certification process, since it's looking like they were totally asleep at the wheel on this one, and pretty much let Boeing sign off on certifying their own work.
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Apr 4, 2019 22:26
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https://twitter.com/washingtonpost/status/1113914415374585857quote:A Boeing-led review of a stall-prevention system suspected in the deadly crashes of two of the company’s new 737 Max jetliners has detected an additional software problem that the FAA has ordered fixed before the planes are cleared to fly again, the company acknowledged Thursday.
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Apr 4, 2019 22:27
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The real question is not "can the planes be made safe" it's "are customers ever going to want to book routes on them again?" The DC-10 was partially killed over public safety perception and that was before the era of social media and 24 hour news cycle. This is going to have a pretty big ripple effect throughout the airline industry. If people shy away from MAX flights, they are going to become uneconomical to fly no matter what.
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Apr 4, 2019 22:45
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standard.deviant posted:I don’t know anything about the units they’re referencing in the report, but am I correct in assuming that if stab trim ran away and they cut it out but couldn’t manually trim it back then they were going to crash regardless of anything else they did? That’s the manual electric trim. There is no indication that they ever touched the trim wheels, which is concerning.
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Apr 4, 2019 22:52
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Rebrand the 737 MAX the “757-300”
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Apr 4, 2019 22:53
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Platystemon posted:Rebrand the 737 MAX the “757-300” Put GEnxs on this long bitch 
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Apr 4, 2019 22:57
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MrYenko posted:That’s the manual electric trim. There is no indication that they ever touched the trim wheels, which is concerning. There's speculation that the high rate of speed combined with high level of trim the system dialed in made it impossible to move the manual trim wheel effectively.
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Apr 4, 2019 23:02
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KodiakRS posted:Prelim report on the Ethiopian crash if it wasn't already posted: https://assets.documentcloud.org/documents/5793877/Preliminary-Report-B737-800MAX-Ethiopia.pdf Some weird stuff in there for sure. At 5:41:46 the FO asks if he can try to trim manually and then responds it isn't working a few seconds later. During that time the pitch trim doesn't change at all. That's a fully manual system, just cables and pulleys to the back. I don't know why it wouldn't work, but before that, the overspend clacker started going off and they exceeded VMO. Maybe they haven't got enough mechanical advantage over the aero forces on the stab to move it during an overspeed? I genuinely don't know, I'm not a 737 expert.
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Apr 4, 2019 23:04
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MrYenko posted:That’s the manual electric trim. There is no indication that they ever touched the trim wheels, which is concerning. It wouldn’t be in the telemetry if it didn’t work... quote:At 05:41:46, the Captain asked the First-Officer if the trim is functional. The First-Officer has replied that the trim was not working and asked if he could try it manually. The Captain told him to try. At 05:41:54, the First-Officer replied that it is not working. So the question is what did the FO do “manually”
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Apr 4, 2019 23:06
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MrYenko posted:That’s the manual electric trim. There is no indication that they ever touched the trim wheels, which is concerning. Yeah it's a bit unclear, but reading between the lines, the FO asks to try to trim it manually, but there's nothing on the recording at that point that the control column trim switches were moved, so you can assume he tried the manual wheel, but you can't be 100% sure from the report.
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Apr 4, 2019 23:07
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^^^ if there isn’t an encoder on the wheels connected to the data recorder we can never be 100% sureFinger Prince posted:Some weird stuff in there for sure. At 5:41:46 the FO asks if he can try to trim manually and then responds it isn't working a few seconds later. During that time the pitch trim doesn't change at all. That's a fully manual system, just cables and pulleys to the back. I don't know why it wouldn't work, but before that, the overspend clacker started going off and they exceeded VMO. Maybe they haven't got enough mechanical advantage over the aero forces on the stab to move it during an overspeed? I genuinely don't know, I'm not a 737 expert. Is it pulleys to the back? Stabilizer control is electrical, not hydraulic according to the report
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Apr 4, 2019 23:08
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hobbesmaster posted:^^^ if there isn’t an encoder on the wheels connected to the data recorder we can never be 100% sure I think it's a chain actually. The manual trim wheels are exactly that, you're physically turning the jackscrew with them once you've cut out the electric trim. The most concerning thing, which may be the "additional software issue" referred to by Boeing/FAA is this: quote:At 05:43:20, approximately five seconds after the last manual electric trim input, an AND automatic This was after the cutout switches were already in cutout. There should have been no further electric authority over the stab at that point, so how did it move nose down electrically?
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Apr 4, 2019 23:32
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Yeah, it looks like from the diagram that the manual wheel turns the gearbox of the jackscrew via mechanical linkage.
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Apr 4, 2019 23:34
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Jealous Cow posted:Put GEnxs on this long bitch loong loooooooong plane
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Apr 4, 2019 23:36
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bull3964 posted:There's speculation that the high rate of speed combined with high level of trim the system dialed in made it impossible to move the manual trim wheel effectively. Supplemental 737 MAX training: leg day.
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Apr 4, 2019 23:38
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There's a small part of me remembering people saying they'd never fly on an Airbus because  Boeing does it right and always allows the pilot to override the flight computer To which I say "what now"
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Apr 4, 2019 23:49
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bull3964 posted:Yeah, it looks like from the diagram that the manual wheel turns the gearbox of the jackscrew via mechanical linkage. Uhh how much effort does that require? Those wheels are in a spot where the Capt or FO could put much force into it.
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Apr 5, 2019 00:02
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dubzee posted:Boeing is in for some pain. unsafe at any altitude!
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Apr 5, 2019 00:04
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dubzee posted:Nader is on about the design itself being defective. Adding the larger engines throws off the CG hence the software being needed to keep the thing from stalling. Updating the software doesn't fix a hardware issue.
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Apr 5, 2019 01:17
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Military jets are primarily known for their maneuverability, though, and the pilot has an exit in case something goes wrong; lower risk, for an actual reward (unstable planes are more maneuverable). A plane with 100s of passengers whose primary task is "fly in a straight line efficiently" has zero reason to be designed with negative stability. Aside from stubbornly maintaining a 50 year old type certificate despite massive design changes like that.
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Apr 5, 2019 01:21
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Fender Anarchist posted:A plane with 100s of passengers whose primary task is "fly in a straight line efficiently" has zero reason to be designed with negative stability. Not true, it brings fuel savings due to a reduction in trim drag. (Well not actually negative stability, but the reduced positive stability that airliners are skirting with)
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Apr 5, 2019 01:24
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hobbesmaster posted:Uhh how much effort does that require? Those wheels are in a spot where the Capt or FO could put much force into it. The WaPo article quotes some expert, FWIW, suggesting that might be a problem: quote:Experts say that the airplane was traveling too fast for the manual trim wheel to be operated. Also, apparently the wrong AoA sensors was reading 75 degrees. I can't imagine that's anywhere near the normal operating conditions for an airliner? ...so this might be even more of an example of computers being stupid than it first seemed. Edit: thinking some more, forcing use of manual trim --- perhaps because they wanted to claim the runaway trim checklist is enough --- as the recovery process for this case is wrong since there was nothing wrong with electric trim, just with the software controlling it, and it seems plausible that electric might have been able to recover. This is of course different from when electric is actually misbehaving, in which case the backup system might just be the best one can do. OddObserver fucked around with this message at 03:45 on Apr 5, 2019 |
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Apr 5, 2019 03:31
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Fender Anarchist posted:Military jets are primarily known for their maneuverability, though, and the pilot has an exit in case something goes wrong; lower risk, for an actual reward (unstable planes are more maneuverable). A plane with 100s of passengers whose primary task is "fly in a straight line efficiently" has zero reason to be designed with negative stability. There are some sweet overreactions ITT, the 737 MAX is not inherently unstable like an F-16, it suffers from a programming flaw.
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Apr 5, 2019 05:26
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A programming flaw in software that was meant to make it fly like a 737NG
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Apr 5, 2019 05:28
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Elviscat posted:There are some sweet overreactions ITT, the 737 MAX is not inherently unstable like an F-16, it suffers from a programming flaw. Also its missing an entire AoA sensor if the MCAS system is truly required for the aircraft to fly.
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Apr 5, 2019 05:42
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Sorry, i read that the bigger engines made it more unstable and made assumptions. Still, it does change the natural handling characteristics.
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Apr 5, 2019 06:02
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bull3964 posted:The real question is not "can the planes be made safe" it's "are customers ever going to want to book routes on them again?" Yeah, this is a thing. I was on an Alaska connecting flight from SEA to SFO and had to reassure a few people when they saw it was a 737 that it was a -900, not a MAX. Alaska bought into the MAX 9, which hasn't actually hit primetime yet, and they don't fly any 8s. BIG HEADLINE fucked around with this message at 06:18 on Apr 5, 2019 |
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Apr 5, 2019 06:08
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