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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

#261

Post by 7952 »

magicalhippo wrote: post #241
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.

I still don't see how a frozen AoA sensor cannot be detected by the reduction in noise or correlation with other sensors (such as gyroscope or accelerometer).

Maybe you could have a pair of vanes. Each vane is physically limited to a portion of possible angles. Vane A would only work above say -10 degrees AOA and vane B below +10 degrees AOA. This would give you a regular test of both sensors when the AoA changes in normal flight. You have more bounding of correct values.

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

#262

Post by user5994461 »

eCa wrote: post #243
erentz wrote: post #43

Earlier quoted context omitted.

> 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…

> Airlines have no choice Anecdotal: I know of at least one family that booked a trip on a non-Boeing airline, at additional cost, to avoid risking being on a Max. Imagine that after the Max is back in service, that there is a serious incident in the first few months - it doesn't have to be fatal, just a close call of some kind - how many more customers will avoid the Max at all costs?

How do you know the plane model before you board? It's not shown when buying the ticket, it's not written on the ticket either.

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

#263

Post by sean_the_geek »

eCa wrote: post #243
erentz wrote: post #43

Earlier quoted context omitted.

> 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…

> Airlines have no choice Anecdotal: I know of at least one family that booked a trip on a non-Boeing airline, at additional cost, to avoid risking being on a Max. Imagine that after the Max is back in service, that there is a serious incident in the first few months - it doesn't have to be fatal, just a close call of some kind - how many more customers will avoid the Max at all costs?

Count one more please. Searched for flight, saw Boing 737, no thank you! Paid premium for Airbus. That’s for three passengers.

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

#264

Post by sean_the_geek »

user5994461 wrote: post #262
eCa wrote: post #243

Earlier quoted context omitted.

> Airlines have no choice Anecdotal: I know of at least one family that booked a trip on a non-Boeing airline, at additional cost, to avoid risking being on a Max. Imagine that after the Max is back in service, that there is a serious incident in the first few months - it doesn't have to be fatal, just a close call of some kind - how many more customers will avoid the Max at all costs?

How do you know the plane model before you board? It's not shown when buying the ticket, it's not written on the ticket either.

Some airlines do! Qatar and Emirates, I think.

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

#265

Post by kmlx »

user5994461 wrote: post #262
eCa wrote: post #243

Earlier quoted context omitted.

> Airlines have no choice Anecdotal: I know of at least one family that booked a trip on a non-Boeing airline, at additional cost, to avoid risking being on a Max. Imagine that after the Max is back in service, that there is a serious incident in the first few months - it doesn't have to be fatal, just a close call of some kind - how many more customers will avoid the Max at all costs?

How do you know the plane model before you board? It's not shown when buying the ticket, it's not written on the ticket either.

but they rotate them quite a lot, don’t they?

i booked a boeing 787 dreamliner but ended up in a crummy 777 from a decade ago.

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

#266

Post by pentae »

sean_the_geek wrote: post #263
eCa wrote: post #243

Earlier quoted context omitted.

> Airlines have no choice Anecdotal: I know of at least one family that booked a trip on a non-Boeing airline, at additional cost, to avoid risking being on a Max. Imagine that after the Max is back in service, that there is a serious incident in the first few months - it doesn't have to be fatal, just a close call of some kind - how many more customers will avoid the Max at all costs?

Count one more please. Searched for flight, saw Boing 737, no thank you! Paid premium for Airbus. That’s for three passengers.

You know the 737 and the 737 MAX are two completely different planes right?

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

#267

Post by ricardobeat »

user5994461 wrote: post #262
eCa wrote: post #243

Earlier quoted context omitted.

> Airlines have no choice Anecdotal: I know of at least one family that booked a trip on a non-Boeing airline, at additional cost, to avoid risking being on a Max. Imagine that after the Max is back in service, that there is a serious incident in the first few months - it doesn't have to be fatal, just a close call of some kind - how many more customers will avoid the Max at all costs?

How do you know the plane model before you board? It's not shown when buying the ticket, it's not written on the ticket either.

It should be there among the flight itinerary data, often hidden behind an accordion or tooltip.

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

#268

Post by zeroone101 »

jussij wrote: post #157
manigandham wrote: post #80

Earlier quoted context omitted.

There's no fundamental design flaw, the aircraft is sound. The problem came from using software systems to artificially make the plane behave like older designs to avoid entirely new training and certifications. Even that would've been acceptable and similar systems are already in use in other planes but it was the inadequate info, redundancy, warnings and controls to disable the system that created the problem. It's…

> There's no fundamental design flaw, the aircraft is sound. From what I have read, the new aircraft design had a habit of raising it's nose when engine power was applied, which put the plane into a situation where it might stall. The MCAS was added to automatically detect this behaviour and stop the nose lifting. So basically, without the MCAS, under certain scenarios the plane had a tendency to want to stall. That…

All planes with under mounted engines pitch up under power. Some more than others. The MAX just happens to do it more than a traditional 737.

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

#269

Post by MaxBarraclough »

erichocean wrote: post #187
TomVDB wrote: post #180

Earlier quoted context omitted.

A different way to look at this is: does this particular perverse incentive justify reduced regulation so that it can’t happen anymore. Even if your assessment is valid, you’d likely be throwing away the baby with the bath water if you’d cut regulation to avoid it.

I would think it would justify additional regulations to allow for something like "upgrades" to existing certifications instead of the binary (full recertification|pretend plane is identical) standard we appear to have today that resulted in the 737 Max tragedy. Is that less regulation? More regulation? I don't know, and I doubt it matters if it's "less" or "more" since the goal is fewer dead people, not passing an i…

> Is that less regulation? More regulation?

You are suggesting stronger regulation of some aircraft ('upgrades', as you rightly say), without weakening regulation for any other aircraft. So it's certainly 'more regulation'.

> I doubt it matters if it's "less" or "more" since the goal is fewer dead people, not passing an ideological Turing test.

It's a political question, so there's at least some question of ideology. Full-bore libertarians would doubtless find some way to oppose your suggestion.

You said regulation caused perverse incentives that ultimately got people killed. It would be more fair to say that a loophole in the regulations, caused the perverse incentive.

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

#270

Post by jussij »

zeroone101 wrote: post #268
jussij wrote: post #157

Earlier quoted context omitted.

> There's no fundamental design flaw, the aircraft is sound. From what I have read, the new aircraft design had a habit of raising it's nose when engine power was applied, which put the plane into a situation where it might stall. The MCAS was added to automatically detect this behaviour and stop the nose lifting. So basically, without the MCAS, under certain scenarios the plane had a tendency to want to stall. That…

All planes with under mounted engines pitch up under power. Some more than others. The MAX just happens to do it more than a traditional 737.

I don't think the problem is pitching behaviour.

The problem is the fact the MCAS is required to fix the pitching problem.

Boeing tried to fix the design issue with a workaround solution only to then find they had created another, even bigger problem.

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