Airline pilots have been complaining for months about Boeing's deathliner

#21

tell me about it. so let me get this straight; boeing calls trump to not to ground the max8, trump calls the head of the FAA, which is or was his fucking private pilot, and the FAA says everythings fine. and then trump tweets about the dangers of too complex systems as proof of non-corruption. are you fucking kidding me?!?

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#22

Just to clarify - Trump tried to install his personal pilot as head of the FAA, but he couldn’t get confirmed, which means that there is no confirmed head of the FAA, only an acting head.

Which is also not great, when you need leadership in an emergency

ETA - and the acting head isn’t his personal pilot either. It’s this guy

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#23

from the wiki-article:

For 16 years, Elwell was a commercial pilot for American Airlines. Elwell also had a role of American Airlines’s Managing Director for International and Government Affairs.

neat. (AA isnt grounding their max8-fleet)

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#24

Even in the event of an unwanted MCAS activation, it can be disengaged momentarily or cut out completely.

The problem, according to Ars Technica, appears to be that in other models of the 737, pulling back on the control stick is enough to disable the MCAS. However, because the 737-MAX 8’s engines are shaped and situated differently, the plane has a tendency to nose up more aggressively than older models (and thus is more likely to accidentally find itself in a stall position). To prevent pilots from accidentally putting the plane into a stall by being unfamiliar with the different flight characteristics of the MAX 8, (essentially, in an attempt to emulate the behavior of older 737 models) the MCAS doesn’t auto-disable when the pilot tries to override it by pulling up. Only manually disabling the MCAS system via a switch will terminate its overriding of the trim controls.

Under most circumstances, this is probably fine. However, in a low-altitude situation with an already-high angle of attack (AOA) like takeoff, malfunctions in the AOA sensor or the MCAS system more broadly are more likely to be difficult to diagnose and correct before the plane noses itself into rapid uncontrolled disassembly. In those circumstances, a pilot’s natural instinct when the plane is nosing down is probably to pull up on the controls. If the plane is fighting that input and not providing the pilot with sufficient information to diagnose the problem, there is precious little time to fiddle with other things, if it even comes to mind to do so. Especially if every other 737 doesn’t require the pilot to take an extra step to disable the thing causing the nose-down.

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#25

Canada has now banned the plane from Canadian Airspace as well, citing “new information”:

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#26

In this case Boeing added the software to compensate for a mechanical deficiency in the plane design. They needed a new more efficient plane to fill the same roles as the 737, but rather than start over with a “clean sheet” plane design which would require years of additional design, testing and certification they modified the existing 737 by putting larger diameter engines that are mounted more forward and lower relative to the plane’s body. The engine placement created a tendency for the plane to “nose-up” when engines are at max thrust during takeoff, which could cause a stall. The MCAS system is meant to push the nose down to prevent that, but obviously the implementation of that system isn’t working out well if a failed sensor or whatever causes it to forcefully nose down even when the pilots don’t want it to.

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#27

exactly.

the FAA statet after the lion air-crash (but not after Ethiopian Flight 302)

This condition, if not addressed, could cause the flight crew to have difficulty controlling the airplane, and lead to excessive nose-down attitude, significant altitude loss, and possible impact with terrain.

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#28

Yep - this is exactly correct and from what I understand there was a faulty sensor in the Lion Air plane that sent incorrect data to the MCAS. The suspicion here was poor maintenance protocols lead them to dispatch the plane when it should have been grounded.

In the recent Ethiopian crash, speculation is the FO had a very low number of hours (~200) so I can see where an unusual flight configuration could have easily confused him to not follow the proper recovery procedure and not manually disengage the system thus causing him to “fight” with the controls which has been reported.

Another pilot weighing in:

I’m not sure if the Lion Air pilots were concerned with the AOA indicator (different from the sensor) and I don’t know how the Lion Air primary flight displays were configured. The sensors were transmitting disagreeing data (20 degree variation) to the flight control computer, but the MCAS, available strictly with autopilot disengaged and flaps up, only took its AOA guidance from the malfunctioning sensor.

My understanding, from reading the report, is that the pilots were struggling with the the nose-down commands the aircraft was independently making, which were countering back pressure on the yoke and nose-up electric trim ‘flicks’ by the hand-flying pilot. This caused the MCAS to cycle on and off 25+ times, each time processing faulty data suggesting the airplane was flying into a stall and thus re-activating, which ultimately overcame the pilots’ efforts to command a climb.

IMO, the biggest issue emerging with the MAX is that the pitch axis augmentation systems (in manual flight only) take data from just one of the two AOA sensors, limiting the fail-safe properties of other automated systems, like yaw damper, which can compare two feeds to diagnose a sensor disagreement. Southwest ordered its airplanes with a AOA sensor disagree annunciation, which is not required, but gives pilots insight and suggests causal factors if an uncommanded nose down pitch trim event is noted.

The forthcoming AD for the 737MAX will likely be a software update to change the architecture of the flight control computer to accept dual-channel AOA input in manual flight, along with a comparison function, for the automated pitch control augmentation systems. The augmentation will automatically disable and annunciate the fault to pilots in the event of an AOA sensor disagree. The capability is there: the autopilot is designed to accept inputs from both sensors and will fault if there is a disagree. The problem is, the AP will fault into manual mode, and manual mode clearly has a shorter progression of > events to a catastrophic outcome…

The starting point is a faulty AOA sensor, which, if undetected and not repaired, can lead to an improper response by a flight control safeguard system that mistakenly concludes the aircraft is approaching a hazardous state. That system is only actuated when other limited criteria are met. From that point, there must be a corresponding incorrect action (or inaction) by the crew to lead to a catastrophic outcome. In all likelihood, a cutout of the automatic stab trim at an earlier point in the Lion Air flight (a procedure for which the crew undoubtedly had training) would have resulted in a safe landing.

So, like anything else, there are multiple, independent factors that combine to create a disaster.

I will caution that my entire analysis is strictly in reference to the Lion Air crash . I know the Ethiopian case involves the same type, with some disturbing similarities, but the truth is the public has little to no objective evidence on which to draw a rational finding. It would therefore be incorrect (but perhaps natural) to impute this discussion to ET302 and further, to conclude that a grounding of the fleet is essential. That determination would be rooted in substantially less factual support, but it’s gaining momentum nonetheless…

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#29

The heart of it is that many experienced people can’t point to what happened until they look at the black boxes.

That’s not an argument to keep flying the planes, it’s just an argument to not point fingers yet.

Even if “Pilots new to the plane were given insufficient training on this plane” is the actual issue, it’s still dodgy to say “We should just keep flying the planes even though we know there’s probably similar cases of inadequate training on this particular plane”.

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#30

Previously he said he would have no qualms flying on one. I’m not sure if that was reassuring, coming from a former astronaut.

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#31

The FAA, which has no head (because Trump nominated his personal pilot and Congress said “no,” and then he never nominated anyone else), and which knew about, and started to address this issue - only to have the efforts shut down along with the rest of the federal government for six weeks. Yeah, that FAA.

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#32

I don’t understand how the planes aren’t grounded in the U.S. – Boeing was already WORKING ON A FIX. A fix means there is a known problem, and a 2nd deadly crash shows that the plane is probably not safe.

Not only that, but the fix was apparently delayed because of the government shutdown, and could have possibly been in place before the Ethiopia disaster.

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#33

Read: NextGen

“The FAA has switched to a satellite-enabled navigation system that is more precise than traditional ground-based navigation aids. Satellites enable the FAA to create optimum routes anywhere in the NAS for departure, cruising altitude, approach and arrival operations.”

Pilot free airplanes is the goal. So, no more pesky complaints about faulty flight control systems or unions.

Note: NextGen is BS. Fast tracked by congress with a shit ton of issues.

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#34

“impact with terrain”-- best euphemism ever.

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#35

Well, well, well…

The right choice.

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#36

I’m sure it was totally his idea and had nothing to do with anything anyone else was doing. He meant to ground them all along.

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#37

Boeing is already painting a picture:

Complete BS. The patch(s) could have been made anytime and FAA could have signed off as soon as the shutdown was over.

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#38

Here’s the time to note that even a broken clock is right twice a day. I doubt he has quite that record, of course.

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#39

IncomparableReadyHornedviper-size_restricted

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#40

Ouch

Prediction: Boeing will issue patches and FAA will approve quickly. Boeing stock will recover. The wild card will be if China’s aviation agency or others will follow suit in the middle of trump’s tariff war.

FAA will still have no administrator.

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