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Someone has watched an AC-130 obliterate a corner of Afghanistan and thought "you know this would make a great show".
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Mar 11, 2019 14:10
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AzureSkys posted:Here's something a bit brighter in the aeronautical insanity category. Oh, so planes can shoot lasers at people on the ground and everyone cheers, but if people on the ground shoot lasers at a plane it's "dangerous" and they go to jail. 
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Mar 11, 2019 14:16
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That was awesome. The icing was the crowd sounded like it was losing its collective mind like they were at the most awesome concert ever put on.
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Mar 11, 2019 14:23
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Finger Prince posted:If it is MCAS related, then the FAA probably steps in and grounds them until they fix it, which will probably be a hasty mandatory AD to deactivate it. Boeing probably eats the manhour cost of implementing it plus lost revenue while they're grounded. That'll be costly, but not the end of the world. Remember that the 787 was grounded for 4 months while they redesigned the battery enclosure, and it's doing fine. That was a much bigger undertaking than a software update and maybe some wiring changes. MCAS can't be just turned off and flown without, it's artificial stability required in order to comply with certification standards, in place in order to compensate for instability contributed by the MAX's nacelles, which are both larger and further forward than previous variants. vessbot fucked around with this message at 14:48 on Mar 11, 2019 |
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Mar 11, 2019 14:23
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Tsuru posted:Then again I'm reading things that the cutouts are not going to disable MCAS, but I have not been able to confirm that with any official documentation. They turn off the trim motors, and thereby disable any electronic system from moving the trim. 737 dudes weigh in? I know we have at least one....
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Mar 11, 2019 14:26
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AzureSkys posted:Here's something a bit brighter in the aeronautical insanity category. Now put the lighting and pyro on the Screamin' Sasquatch. And turn the music up. J85s are LOUD.
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Mar 11, 2019 14:28
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MCAS uses the trim motors to alter the trim of the airplane during very specific flight regimes. Regimes that you would not normally encounter during normal operation. The two stab trim cutout switches cut off all electrical power to the motors, leaving you with only the manual trim wheels to trim the airplane.
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Mar 11, 2019 14:32
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Finger Prince posted:Bob, we need you to cause a distraction so we can sneak past those guards! Basically an airborne https://www.youtube.com/watch?v=e0xPCas2tHQ
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Mar 11, 2019 14:42
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poo poo! We were so distracted we forgot to sneak past the guards!
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Boeing stock loving tanked on open. It's already kind of clawing it's way back up though.
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Mar 11, 2019 15:03
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Arson Daily posted:MCAS uses the trim motors to alter the trim of the airplane during very specific flight regimes. Regimes that you would not normally encounter during normal operation. The two stab trim cutout switches cut off all electrical power to the motors, leaving you with only the manual trim wheels to trim the airplane. Does the pilot also need to manually zero the trim position after turning off the motors if MCAS changed it too much?
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Mar 11, 2019 15:22
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OddObserver posted:Does the pilot also need to manually zero the trim position after turning off the motors if MCAS changed it too much? I believe so? The electric trim is moving the wheels. In looking for the answer however, I found this little tidbit off that uk 737 technical site: http://www.b737.org.uk/flightcontrols.htm#Stab_Trim quote:[Moving the control column in the opposite direction to electric trim will stop the trim, unless the STAB TRIM switch is set to OVERRIDE. The 737 max behaves radically differently from every other 737?!
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Mar 11, 2019 15:30
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Finger Prince posted:Remember that the 787 was grounded for 4 months while they redesigned the battery enclosure, and it's doing fine. That was a much bigger undertaking than a software update and maybe some wiring changes.
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Mar 11, 2019 15:31
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KOTEX GOD OF BLOOD posted:The difference is that no 787s crashed as a result of the battery issues. The MAX 8 hasn’t been out that long and you have two hull loss incidents with 100% fatality. Even if the service consequences are ultimately similar, the loss of public and investor confidence over this is going to be massive. Boeing dropped 12 percent of its share value this morning, and IDK about you but I don’t really want to fly in a MAX 8 anytime soon. Boeing stock took a 12% hit in the wake of the 787 battery grounding in 2014 as well. It recovered nicely. Look I'm not saying this isn't bad, but it's not the end of the world, and it's not like it's some impossible thing to fix. How many people stopped flying on airbusses within a few months of a few of them crashing? Personally I won't be wanting to fly on a Max anytime soon because the seats in the back are maximum sardine can, not because some outlier condition could cause them to crash if the pilots aren't up to speed on what to do when it happens.
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Mar 11, 2019 15:50
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Finger Prince posted:Boeing stock took a 12% hit in the wake of the 787 battery grounding in 2014 as well. It recovered nicely. Look I'm not saying this isn't bad, but it's not the end of the world, and it's not like it's some impossible thing to fix. How many people stopped flying on airbusses within a few months of a few of them crashing? Personally I won't be wanting to fly on a Max anytime soon because the seats in the back are maximum sardine can, not because some outlier condition could cause them to crash if the pilots aren't up to speed on what to do when it happens. Which airbus type had two crashes within a few months a couple of years after their introduction?
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Mar 11, 2019 15:56
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fknlo posted:Boeing stock loving tanked on open. It's already kind of clawing it's way back up though. Wow how deep does this trim tab problem go?
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Mar 11, 2019 16:00
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Nebakenezzer posted:It's like unstealth The new Wild Weasel program seems low budget, but effective.
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Mar 11, 2019 16:02
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Finger Prince posted:some outlier condition could cause them to crash if the pilots aren't up to speed on what to do when it happens. Tsuru posted:If you need all four hands on the yoke to keep it at least level a few hundred feet off the ground going 400 knots with extreme nose down elevator trim you're going to have a grand time reaching for the 2 stab trim cutout switches and turning the wheel manually. Then again I'm reading things that the cutouts are not going to disable MCAS, but I have not been able to confirm that with any official documentation.
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Mar 11, 2019 16:07
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ManifunkDestiny posted:Wow how deep does this trim tab problem go? 
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Mar 11, 2019 16:18
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ManifunkDestiny posted:Wow how deep does this trim tab problem go? The stock hasn't gone full Alaska yet...
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Mar 11, 2019 16:21
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Wasn't it last year or 2 years ago that a commercial flight had problems maintaining speed and altitude on take off and had to return? I think it was somewhere in the east. Does anyone recall which airline or plane it was?
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Mar 11, 2019 16:25
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I don't think it is just me being contrarian, I like every one of these notional F-14 designs better than the one that actually flew.  The fixed wing with the crazy wide planform, and the one with the shoulder mounted intakes for people who really don't like situational awareness are my favorites.
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Mar 11, 2019 16:26
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March of the Pigs posted:Wasn't it last year or 2 years ago that a commercial flight had problems maintaining speed and altitude on take off and had to return? I think it was somewhere in the east. Does anyone recall which airline or plane it was? I thought it was the same plane that later went down? Yeah lion air 610.
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Mar 11, 2019 16:27
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KOTEX GOD OF BLOOD posted:It seems it's less that pilots just aren't "up to speed" and more that the procedure isn't feasible in the situation you'd need to use it: Tsuru is incorrect. Stab trim cutout fully removes electrical power from the stab trim actuator. The EAD advice is to disengage AP and attempt to regain trim control with the electric trim switches on the yoke, and if that doesn't work, select cutout and leave it there and manually trim the stab for the remainder of flight. http://publicapps.caa.co.uk/modalapplication.aspx?appid=11&mode=detail&id=8913
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Mar 11, 2019 17:01
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Plinkey posted:I thought it was the same plane that later went down? I thought there was an incident were the pilot managed to bring it back around successfully. This was the same plane that crashed in the Lion Air flight?
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Mar 11, 2019 17:51
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March of the Pigs posted:I thought there was an incident were the pilot managed to bring it back around successfully. This was the same plane that crashed in the Lion Air flight? Yeah the wiki reads like it had a similar issue the previous day/flight but the pilots were able to land, so an AoA sensor was replaced or something and it was flagged as good to go the next morning and crashed 12 minutes after takeoff.
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Mar 11, 2019 17:58
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Finger Prince posted:Tsuru is incorrect. Stab trim cutout fully removes electrical power from the stab trim actuator. The EAD advice is to disengage AP and attempt to regain trim control with the electric trim switches on the yoke, and if that doesn't work, select cutout and leave it there and manually trim the stab for the remainder of flight. A runaway trim condition may make it very difficult to perform any procedure. I think I linked a write up of a colgan crash when Lion air went down: https://www.planeandpilotmag.com/article/trim-trouble/ This is on a beech 1900, not a 737 but illustrates the problem here. The crew immediately recognized the issue: quote:The plane departed runway 24 at Hyannis at 3:38 p.m. Shortly after takeoff, the flight crew declared an emergency and reported a “runaway trim.” The airplane flew a left turn and reached an altitude of approximately 1,100 feet. After the flight crew requested to land on runway 33, no further transmissions were received. They correctly applied the procedures to disconnect electric trim... quote:At 3:38:50, the captain stated, “Roll back, roll back, roll back, roll back, roll back.” According to the DFDR, the elevator trim then moved from approximately minus-three degrees to minus-seven degrees at a speed greater than the capacity of the electric-trim motor. Next, the captain stated, “Do the electric trim disconnect.” At 3:39:04, the captain instructed the first officer to “go on the controls” with him. But since it was already full pitch down... quote:The elevator trim system cockpit controls consisted of a manual trim wheel and two switches on each yoke, which activated an electric elevator trim motor. NTSB investigators calculated that at the peak out of trim condition, the flight crew was attempting to counteract control column forces of 250 pounds. Whats the full force required on a 737's control column? More? Less? Seems like it'd be kinda hard to work when you're trying to pull 250 lbs.
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Mar 11, 2019 17:58
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hobbesmaster posted:A runaway trim condition may make it very difficult to perform any procedure. I think I linked a write up of a colgan crash when Lion air went down: https://www.planeandpilotmag.com/article/trim-trouble/ From what I can tell, a beech 1900 doesn't have hydraulic flight controls. I doubt you'd be pulling that hard on a 737 but that's just speculating. The AD mentions "initially, higher control forces may be needed to overcome any stabilizer nose down trim already applied", but doesn't specify how much more.
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Mar 11, 2019 18:09
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Plinkey posted:Yeah the wiki reads like it had a similar issue the previous day/flight but the pilots were able to land, so an AoA sensor was replaced or something and it was flagged as good to go the next morning and crashed 12 minutes after takeoff. Ah okay, thanks. As for runaway stab trim, on the CRJ900 it actually doesn't take much force to override it, but doing it for 20 minutes straight is very fatiguing. My sim instructor decided to "let" me keep flying and land the plane. My arms were burning when I finally let go. It my not have actually been 20 minutes, but it sure felt like it.
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Mar 11, 2019 18:19
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This is something I don't understand... for anything more complicated than a general aviation aircraft, why would they design the aircraft to provide more control feedback than a reasonably strong pilot could easily overpower? Why would Boeing make it so that two adults need to strain like crazy to pull the yoke when (as I understand it) there's not a direct link between yoke and control surfaces anyways? I'm sure there's a reasonable explanation for this, I just don't have the engineering knowledge to understand.
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Mar 11, 2019 18:38
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kathmandu posted:This is something I don't understand... for anything more complicated than a general aviation aircraft, why would they design the aircraft to provide more control feedback than a reasonably strong pilot could easily overpower? Why would Boeing make it so that two adults need to strain like crazy to pull the yoke when (as I understand it) there's not a direct link between yoke and control surfaces anyways? Not sure if this is relevant here, but legally the 737 Max 8 launched in 2018 is a variant of a plane certified in 1967. This can lead to some weird things.
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Mar 11, 2019 18:53
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kathmandu posted:This is something I don't understand... for anything more complicated than a general aviation aircraft, why would they design the aircraft to provide more control feedback than a reasonably strong pilot could easily overpower? Why would Boeing make it so that two adults need to strain like crazy to pull the yoke when (as I understand it) there's not a direct link between yoke and control surfaces anyways? Because the artificial feel wouldn’t feel right if it didn’t, and could lead to possible over controlling.
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Mar 11, 2019 18:56
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kathmandu posted:This is something I don't understand... for anything more complicated than a general aviation aircraft, why would they design the aircraft to provide more control feedback than a reasonably strong pilot could easily overpower? Why would Boeing make it so that two adults need to strain like crazy to pull the yoke when (as I understand it) there's not a direct link between yoke and control surfaces anyways? I'm not agreeing that that's the case, but until very recently, Boeing has kept a direct link to the flight controls with cables and pulleys. How they feel is very much a factor of what their customers and their management (generally pilots and former pilots, especially back in the day) believed an aircraft should feel like. That way of thinking took a long time to shake, and it wasn't really until Airbus came along with true FBW that changed those preconceptions. There's still plenty of pilots out there who believe the Airbus way is wrong and a certain amount of force feedback is good and proper. None of those people are engineers.
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Mar 11, 2019 19:02
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kathmandu posted:This is something I don't understand... for anything more complicated than a general aviation aircraft, why would they design the aircraft to provide more control feedback than a reasonably strong pilot could easily overpower? Why would Boeing make it so that two adults need to strain like crazy to pull the yoke when (as I understand it) there's not a direct link between yoke and control surfaces anyways? Maybe it's not control feedback, but if the plane senses it's stalling through various sensors it will "push" the nose forward to break the stall and recover. In the CRJ900 that's about 80lbs, I think, someone correct me if I'm wrong. That's enough to yank the controls out of your hands and start the recovery process. Your right, any reasonably healthy pilot can over power that if they want. Maybe the MAX is designed to overpower any pilot's attempts to overpower the plane and start an automatic recovery process, but if something is really wrong with the sensors it will keep pushing down. Pure conjecture on my side though.
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Mar 11, 2019 19:04
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Finger Prince posted:I'm not agreeing that that's the case, but until very recently, Boeing has kept a direct link to the flight controls with cables and pulleys. How they feel is very much a factor of what their customers and their management (generally pilots and former pilots, especially back in the day) believed an aircraft should feel like. That way of thinking took a long time to shake, and it wasn't really until Airbus came along with true FBW that changed those preconceptions. There's still plenty of pilots out there who believe the Airbus way is wrong and a certain amount of force feedback is good and proper. The controls in a Boeing just go to hydraulic actuators, there is no direct connection from the yoke to the flight controls, the feel is all artificial.
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Mar 11, 2019 19:06
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A 737-900 lost an engine last night near Houstonquote:A jetliner landed safely at Bush Airport after passengers reported hearing a bang before an engine caught fire during their flight from New Jersey to Houston late Sunday.
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Mar 11, 2019 19:10
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e.pilot posted:The controls in a Boeing just go to hydraulic actuators, there is no direct connection from the yoke to the flight controls, the feel is all artificial. Ah, yes you're right. My bad. I guess what I was thinking about is the artificial feel being physically driven by the flight control monkey motion, rather than just being a set of springs/cams that aren't connected to anything external to the control (yoke or stick).
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Mar 11, 2019 19:23
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hobbesmaster posted:The 737 max behaves radically differently from every other 737?! It's not really appropriate to think of the MAX as really related to the 737-200 or whatever. There are four generations: 737-100/200/200adv - the original things with low bypass turbofans, almost entirely out of service except for cargo, remote ops, research, etc 737-300/400/500 - called Classics, first with high-bypass CFMs, some wing changes, stretched, new avionics 737-600/700/800/900 - Next Gens, bigger engines, more wing, more fuel, bigger overall sizes available, glass cockpit 737-MAX - again an "incremental" improvement but with a lot of new stuff and a lot of redesign to accommodate new stuff there was a famous incident, Kegworth Air Disaster, in the UK, where a crew transitioning from -200s to the -400 did not realize or forgot that bleed air came from the opposite engine so they shut down the functioning engine by mistake  point being, a lot has changed with each successive 737 generation besides just size
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Mar 11, 2019 19:39
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KYOON GRIFFEY JR posted:It's not really appropriate to think of the MAX as really related to the 737-200 or whatever. Well yes and no. There are big differences, as you noted. The biggest 737 has something like twice the max weight of the original. And the giant nacelles. But at the same time, a lot of things have been kept the same, and artificially forced to do so by the constraint of being under the original type certificate. Like the control system, the steampunk overhead, ancient warning system, etc. And it's this interplay of old and new that has lead to some of the problems. Like I mentioned earlier the instability from the big, forward-sitting nacelles. If the plane was a clean sheet design, it would have simply had a bigger tail to begin with, appropriate for the stability requirement of the current airframe. But since it's an increment over a previous design with a restriction of keeping costs down, they didn't change the tail (since that is avoidable) and put in MCAS as a hodge podge bandaid fix in software instead... on top of STS, another software bandaid already pre-existing from a generation or 2 before that, that does a very similar thing but over a different regime! The further you stack ad hoc bandaids on top of ad hoc bandaids, sooner or later things might unravel.
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Mar 11, 2019 20:23
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Right, there is a lot of stuff still common for various reasons - I'm just responding to the idea that it's particularly weird that this generation of the 737 does something totally different form preceding generations.
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Mar 11, 2019 20:36
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March of the Pigs posted:Maybe it's not control feedback, but if the plane senses it's stalling through various sensors it will "push" the nose forward to break the stall and recover. In the CRJ900 that's about 80lbs, I think, someone correct me if I'm wrong. That's enough to yank the controls out of your hands and start the recovery process. Your right, any reasonably healthy pilot can over power that if they want. Maybe the MAX is designed to overpower any pilot's attempts to overpower the plane and start an automatic recovery process, but if something is really wrong with the sensors it will keep pushing down. Pure conjecture on my side though. I'm very conscious of the fact that I'm probably making a low-information dumbass "common sense" suggestion here, but: there has to be some kind of middle ground between "the controls feel the right way and respond predictably" and "deadlift 300 pounds or this plane will flip and you will all die bitch"
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Mar 11, 2019 20:47
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