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

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

#231

Post by Theodores »

staunch wrote: post #47
djsumdog wrote: post #28

What is the endgame now for 737 MAX planes? Every airline using them has had several weeks to totally reorganize to deal with these huge missing parts of their fleets. Boeing keeps talking about fixing them and putting them back in the air, but I dunno. At this point, it should be agreed the fundamental design flaws are serious, and Boeing should have simply made a brand new plane, with much more modern controls and…

Now imagine if Boeing had created a brand new design instead of the 737 MAX and it had some mysterious fatal flaw as well? Second System Syndrome is something every engineer should understand. There's just no good reason to suspect a brand new design would've been bug free or easier to debug than the 737 MAX. The 787s or A320neos could start dropping out of the sky at any minute. Maybe their carbon fiber panels start…

They should also announce a new aircraft design, a full replacement that is from blank canvas. There might not be that many sales in the sector if the humans are going to take climate change seriously but we all know that isn't going to happen and that Boeing need a fresh design.

The fresh design could tackle problems such as noise in a new way in order to get new customers.

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

#232

Post by CaptainZapp »

djsumdog wrote: post #28

What is the endgame now for 737 MAX planes? Every airline using them has had several weeks to totally reorganize to deal with these huge missing parts of their fleets. Boeing keeps talking about fixing them and putting them back in the air, but I dunno. At this point, it should be agreed the fundamental design flaws are serious, and Boeing should have simply made a brand new plane, with much more modern controls and…

Airbus, Bombardier and others will probably make a lot out of this disaster

I don't think so. Traditionally manufacturers and airlines never argue about a security incident of the competition. I only know of one issue were this unwritten rule was not respected.[1]

[1] https://en.wikipedia.org/wiki/Trump_Shuttle

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

#233

Post by CaptainZapp »

erentz wrote: post #43
djsumdog wrote: post #28

What is the endgame now for 737 MAX planes? Every airline using them has had several weeks to totally reorganize to deal with these huge missing parts of their fleets. Boeing keeps talking about fixing them and putting them back in the air, but I dunno. At this point, it should be agreed the fundamental design flaws are serious, and Boeing should have simply made a brand new plane, with much more modern controls and…

> What is the endgame now for 737 MAX planes? The bugs will be addressed and they'll still fly. Airlines have no choice, there's a limited capacity in the world for airplane construction, several thousands of orders on the books for the 737 and 320 waiting to be filled. What can an airline do? They can cut back some orders but not all orders. > I'd honestly like to see the 737 MAX taken out of service and Boeing simp…

The bugs will be addressed and they'll still fly. Airlines have no choice, there's a limited capacity in the world for airplane construction, several thousands of orders on the books for the 737 and 320 waiting to be filled

While true I don't think that airlines and regulators will go for it, if there's even the slightest risk of an additional accident. No matter what.

And Boeing's "communcation strategy" after the incidents doesn't really help to instill confidence in the plane.

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

#234

Post by cardinalfang »

__m wrote: post #202
Xixi wrote: post #176

Earlier quoted context omitted.

The A350 has 4 AoA sensors: I suspect it is a lesson learned from an A320 that had 2 AoA sensors froze in the same position, outvoting the only AoA sensor that was still working. In other words: failures are not always independent.

Wouldn’t they eventually all freeze at roughly the same position when the AoA doesn’t change for a while? Can’t they be heated?

The A350 has two types of AoA sensor - vanes and multifunction probes - which should reduce the chance of everything failing together.

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

#235

Post by the_mitsuhiko »

jwr wrote: post #155
djsumdog wrote: post #28

What is the endgame now for 737 MAX planes? Every airline using them has had several weeks to totally reorganize to deal with these huge missing parts of their fleets. Boeing keeps talking about fixing them and putting them back in the air, but I dunno. At this point, it should be agreed the fundamental design flaws are serious, and Boeing should have simply made a brand new plane, with much more modern controls and…

I think the 737 MAX should be properly re-certified as a new airplane once the "fixes" are implemented. The whole idea that you can significantly alter an existing airplane by mounting larger engines more forward, add new automatic systems, and still pretend that it's the same airplane, is flawed.

The 737 MAX cannot be certified as a new plane so that is not an option.

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

#236

Post by nwallin »

CydeWeys wrote: post #115
nwallin wrote: post #83

Earlier quoted context omitted.

The 757 "max" is a 767. 757s and 767s share a common type rating. It's not so much that the pilot pool is lacking, it's that a lot of airlines have a pool of existing 737 pilots already on their payroll. If you need to lay off half your employees, and replace them with an entire new pool of people, half of them are going to be terrible employees, and it will take you years to weed out the bad ones. For better or wors…

Huh? There's no such thing as a "737 pilot", there is a "pilot with 737 type rating". It's the whole "becoming a pilot in the first place" part that's hard, not certifying a new type. Plenty of pilots are certified to fly multiple types. The fundamentals of flight are the same across all planes. The airlines would've just had to retrain their existing pilots to fly the new type. It's not nothing, but it's a lot less…

I think you're severely underestimating the time, effort, and money involved in retraining into a new type rating. Usually the process is that the pilot takes a job running air-freight in their new desired type rating. There isn't any money in that, either for the pilot or the airline. You're correct that the fundamentals are the same, but the regulatory burden is enormous.

If getting a new type rating was cheap, this whole 737 max debacle never would have happened. Boeing would have just told everyone the 737 line was done, and to retrain into 767s or 787s, and for anyone who wanted to stick with the 737 to pound sand.

If it was cheap and/or easy for Boeing to tell airlines and/or pilots to get a new type rating, they gladly would have sold them 767s which do everything the 737 MAX does. (it does) They've probably already told them that and they've said no. And Boeing made the 737 MAX with the same type rating as the regular 737. Which is why we're here.

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

#237

Post by CydeWeys »

sjwright wrote: post #199
CydeWeys wrote: post #146

Earlier quoted context omitted.

These planes cost nearly $100M each; how can adding another AoA sensor the size of your hand be that much in the grand scheme of things? https://i.kinja-img.com/gawker-media/image/upload/t_original... Note that the 737 already has two such sensors, but only consults one at a time for MCAS, so there'd be a software change required in addition to adding a new sensor.

Surely they can predict the expected/likely value of an AoA sensor with all of the other telemetry available to an aircraft computer. Surely in combination with software fixes to ensure that both sensors are factored in, they could augment with that computed value to pick a sensor in the case of disagree. If the needed telemetry is already exposed to MCAS, it could all be fixed in software.

MCAS will fly the aircraft into the ground, and has already killed >300 people. These sensors are safety-critical and should not be cheaped out on. A software-only fix is not good enough when the standard in the industry is to have triply redundant systems for safety-critical systems. This is one of those things we learned at the cost of a lot of blood.

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

#238

Post by CydeWeys »

dmix wrote: post #148
CydeWeys wrote: post #146

Earlier quoted context omitted.

These planes cost nearly $100M each; how can adding another AoA sensor the size of your hand be that much in the grand scheme of things? https://i.kinja-img.com/gawker-media/image/upload/t_original... Note that the 737 already has two such sensors, but only consults one at a time for MCAS, so there'd be a software change required in addition to adding a new sensor.

I'd just imagine coordinating with every airport and airport mechanic team to go through this process, have some integration work with the MCAS which has to be done very carefully and thoroughly. Everything is more expensive when you have a super high level of risk management and are working with large bureaucratic organizations like airlines and the FAA. But yes it's certainly not impossible sounding. It's like a mi…

Hundreds of people are already dead because of this. It's the very minimum they can do to prevent more deaths. Whatever the cost is of adding another sensor will be less than the cost of another crash.

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

#239

Post by [deleted] »

bronson wrote: post #221
manigandham wrote: post #210

Earlier quoted context omitted.

Actual engineers do care about the "why" since that's what matters. Otherwise don't bother flying on any aircraft since all models have crashed at some point.

Your second sentence is too glib. By just about any statistic you want to look at, the MAX-8 has an abysmal safety record. Probably worse than any other aircraft in revenue flight. It's perfectly rational to look at the results, regardless of "why", and decide that the risk is just too great.

[deleted]

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

#240

Post by CydeWeys »

kortilla wrote: post #181
CydeWeys wrote: post #109

Earlier quoted context omitted.

The larger point is that the 737 is a highly antiquated design by this point. The cockpit has screens that emulate old analog displays to maintain common type rating, even though much better ways of displaying that data now exist. The plane's controls are highly manual, which are a negative now that fly-by-wire and autopilots are mature and very good. Hell, the entire plane sits so low to the ground because it was de…

>so low to the ground because it was designed to support a non-jetway use case (which is now non-existent) Complete bullshit. I’ve boarded/deplaned without a jetway in Beijing, SLC, JAC, and AMS in the last couple of years alone.

I meant to say "no ground support whatsoever". I've deplaned 737s and 320s on the tarmac recently too (at big airports), and they used mobile stairs. It's the stairs integrated into the aircraft itself that the 737 was designed around, and that's what's antiquated. Hell, just flying the stairs around with you is very fuel inefficient.
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