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Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

seattletimes.com

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Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#311

Post by salawat »

theclaw wrote: post #216
davewasthere wrote: post #66

Earlier quoted context omitted.

Yeah, but who is going to want to fly in one again? Even working in aviation in the past and knowing that they've probably nailed the issue, I'd still be less than keen.

Boeing could simply rebrand the plane. Take ‘MAX’ out of the name, call it a 737-8. I think most people have absolutely no idea what model of plane they’re flying on anyway.

That is a despicable, and dishonest thing to do, and there are people who are more than happy to act as repeaters to make sure people know Boeing's NewPlane (TM) is just a rebrand of the MAX, with a healthy dose of "this is how stupid Boeing thought you were."

Such a move would be ill-advised.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#312

Post by salawat »

staunch wrote: post #283
smadurange wrote: post #192

Earlier quoted context omitted.

Airbus uses software to enhance safety. MCAS is trying to fix a very specific and a potentially dangerous issue while keeping it from the pilots. So, I'm not sure if there's a good analogy there.

In both cases the software was designed to prevent the pilot from stalling the aircraft i.e. to enhance safety. And yet hundreds of people died in Air France 447 because the pilot stalled the aircraft when sensor failure disabled the Airbus software without the pilot realizing it. In the case of MCAS, people died because the Boeing software didn't disable itself due to sensor failure. Definitely not the same issue bu…

Also note, Airbus has had issues where pilots are so used to the machine not letting them do something stupid, that direct law has caught them by surprise.

Automation creates complacency, which can be lethal when things go wrong.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#313

Post by acqq »

manigandham wrote: post #310
acqq wrote: post #306

Earlier quoted context omitted.

> The artificial behavior would be fine if the pilots actually knew it was artificial and how it was being done. If I remember correctly, the behavior you promote as "fine" is forbidden by the regulators, and not accidentally.

If it’s prohibited then how was it certified?

> If it’s prohibited then how was it certified?

Without the active MCAS the plane would have not been certified because the behavior of controls is then not inside of the prescribed limits.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#314

Post by salawat »

CamperBob2 wrote: post #303
blattimwind wrote: post #286

Earlier quoted context omitted.

> Remind me, when's the last time we had a major fatality incident in the US domestic passenger airline business? Doesn't really matter much. Incidents in aviation that can happen on continent X could usually have happened on any continent.

A good counterexample: in the Lion Air case, at least one planeload of passengers came within a hair's-breadth of disaster prior to the fatal crash. The pilots figured out what to do in time, in part because a third pilot was available to RTFM while the other two flew the airplane. However, that crew not only didn't take any action to remove the aircraft from service, they apparently didn't even bother to leave a Pos…

He didn't RTFM actually. They performed Crew Resource Management, and he was able to focus his attention on controls the other two pilots didn't have time to manage. Hence noticing the trim wheels running amok.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#315

Post by CamperBob2 »

salawat wrote: post #314
CamperBob2 wrote: post #303

Earlier quoted context omitted.

A good counterexample: in the Lion Air case, at least one planeload of passengers came within a hair's-breadth of disaster prior to the fatal crash. The pilots figured out what to do in time, in part because a third pilot was available to RTFM while the other two flew the airplane. However, that crew not only didn't take any action to remove the aircraft from service, they apparently didn't even bother to leave a Pos…

He didn't RTFM actually. They performed Crew Resource Management, and he was able to focus his attention on controls the other two pilots didn't have time to manage. Hence noticing the trim wheels running amok.

Good point, I was just echoing some of the earliest news accounts there. Those stories came out before it became apparent that the flight manuals didn't actually have much useful information on the subject.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#316

Post by avar »

hakfoo wrote: post #301
avar wrote: post #223

Earlier quoted context omitted.

> the plane CLEARLY flies differently to a 737[...] There's no such thing as "a 737". A 737-600 is 31 meters long[1], and a 737-900ER is 42 meters. Both share the same type rating with the MAX[2], and have the same 36 meter wingspan. That's going from a length:span ratio of 0.86:1 to 1.17:1, you think those sort of airframe changes don't make for a plane that flies differently? Maybe the whole notion of a "common typ…

I think it's all about how far off the mean you are. Consider cars: You can get most full-size sedans with either four or six cyliner engines, manual or automatic transmission, and regular or sporty suspensions. That's potentially eight different sets of handling characteristics. But they're all going to be in a fairly narrow cluster of "this still drives pretty much like a Camry." When you decide "instead of the six…

The question is whether a Camry with that V8 engine is as different from the less powerful of a Camry variant as it is from a Ford F-150. That's what the type rating is about.

The 737-100 had 62 kN of thrust, the 737 600-900 up to 120 kN[1], that whole line (and beyond) shares the same type rating.

1. https://en.wikipedia.org/wiki/Boeing_737#Specifications

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#317

Post by manigandham »

acqq wrote: post #313
manigandham wrote: post #310

Earlier quoted context omitted.

If it’s prohibited then how was it certified?

> If it’s prohibited then how was it certified? Without the active MCAS the plane would have not been certified because the behavior of controls is then not inside of the prescribed limits.

I was talking about the the artificial behavior, so if it was certified then it was deemed allowable to have a stability control system maintain the necessary behavior.

If the plane must have natural behavior, then MCAS would not allow it to be certified because it's artificial control.

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#319

Post by [deleted] »

sabujp wrote: post #151

I don't understand why there's not something that just allows the pilots to completely turn off all autopilot systems without also turning off hydraulic supports? It seems like if they turn off autopilot it makes the steering become not powered or something?

[deleted]

Re: Boeing altered key switches in 737 MAX cockpit limiting ability to shut off MCAS

#320

Post by skybrian »

CydeWeys wrote: post #133
skybrian wrote: post #121

Earlier quoted context omitted.

Yes, it doesn't matter which two countries it was, but it's fine to point out that many airlines in many countries didn't see these problems. The planes flew in many places every day with no trouble. You are calling me out over nothing. This is uncharitable, to say the least. Why make trouble?

There were "only" two instances (which killed >300 people) before the plane was yanked from the air entirely. That means that, roughly speaking, it was only going to happen in two countries at all, or one really unlucky country. So there's no use in pointing out that it didn't happen in many more countries, because that would have required dozens more accidents with tens of thousands of deaths, which was simply never…

You're explaining my own reasoning and then telling me how I'm wrong.

Talking about countries is just another way of saying that the plane was flying in many places all over the world and the risk of accident, despite these horrible accidents, was never very high. As you say, would never happen.

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