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U.S. FAA proposes requiring key Boeing 737 MAX design changes

reuters.com

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Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#91

Post by throwaway29102 »

kube-system wrote: post #79
yellow_postit wrote: post #12

Earlier quoted context omitted.

Given the amount of additional scrutiny these models are getting I wouldn’t be surprised if in the long run of their lifetime they have a better safety record.

This has happened with other planes before, like the DC-10.

They didn’t try to fix the DC-10’s design problem (outward-opening doors causing explosive decompression) with a software fix. Also, the aircraft never regained the trust of the flying public, relegating it to freighter duty. That doesn’t seem like a desirable outcome for Boeing or the MAX’s buyers.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#92

Post by Animats »

That's a fairly mild fix. the FAA could have required that the MCAS system meet the requirements for a full authority fly-by-wire system.

Boeing built an unstable airplane, then tried to fix it with a tweak to a non-redundant auto-trim system. If this was a full fly by wire plane, like the 777 and later, or the Airbus 320 and later, there would be much more sensor and compute redundancy. Plus the fly by wire system has more awareness of the overall flight situation.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#93

Post by briandear »

Nacdor wrote: post #6

Given the option, would anyone choose to book a trip on one of these new Boeing aircraft rather than anything else? I know I wouldn't, my family wouldn't, and none of the friends or co-workers I've discussed this with would. Something tells me airlines are going to be making it even more difficult to determine which aircraft you'll be flying on when you book a ticket. As far as I know they're not required to tell you…

It would depend on the airline. Southwest Airlines, definitely. Some third world airline where their pilots come through pilot mills and take the controls at less than 500 hours? No way. But that is true with any airplane, not just the Max. Statistically Southwest Airlines should have had a crash, yet it was Ethiopian and Lion Air that did. Given the maintenance and pilots history of Lion Air, a crash wasn’t unexpected. Is it a coincidence that no European, American, or Canadian 737s crashed despite flying an order of magnitude more flights in the airplane? There was a recent report that said that a large number (hundreds) of Pakistani airline pilots didn’t have legitimate licenses. That kind of thing is more scary than the 737 Max.

The copilot on the Ethiopian airlines crash had just 200 hours of experience. On a US airline, the minimum is 1500 hours. The cause of the malfunction is certainly worthy of discussion, but both the Lion Air and Ethiopian crashes could have been prevented with better pilot actions.

https://www.washingtonpost.com/business/2019/03/21/ethiopian...

https://www.wsj.com/articles/maintenance-lapse-identified-as...

Talking to actual pilots that operate internationally and it’s pretty clear that there are some scary operations going on.

Southwest Airlines requires at least 1000 hours of turbine time as a minimum, along with an ATP rating. At Ethiopian, you could get hired with zero hours of turbine time. That’s the real scandal that these airlines put kids in the right seat of a big airliner with less experience than required to get your single engine commercial license in the US.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#94

Post by l31g »

linuxftw wrote: post #19
zaroth wrote: post #3

https://www.faa.gov/news/media/attachments/19_035n-R3-8-3-20... > "To address the unsafe condition, the FAA proposes to require four design changes: (1) installing updated flight control software (with new control laws) for the FCC operational program software (OPS), (2) installing updated MDS display processing computer (DPC) software to generate an AOA disagree alert, (3) revising certain AFM flightcrew operating p…

To me, this reads as a total reduction in the effectiveness of the MCAS. We still have no indication that operating the aircraft without MCAS is safe, therefor if the system fails during a critical moment or is otherwise unable to account for the increased angle of attack, we could see jets plummet to the earth in a stall scenario. Absolutely the worst thing that could happen.

MCAS is only useful in very extreme situations rarely seen in normal flight. Most pilots will never be in a situation where MCAS is useful.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#95

Post by kube-system »

throwaway29102 wrote: post #91
kube-system wrote: post #79

Earlier quoted context omitted.

This has happened with other planes before, like the DC-10.

They didn’t try to fix the DC-10’s design problem (outward-opening doors causing explosive decompression) with a software fix. Also, the aircraft never regained the trust of the flying public, relegating it to freighter duty. That doesn’t seem like a desirable outcome for Boeing or the MAX’s buyers.

For sure, the horses have already left the barn as far as reputation is concerned. But even freighter duty is infinitely better than what they currently -- over-sized paperweights.

Although I'm sure low-cost carriers or developing nations will gladly fly them at the right price.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#96

Post by rsynnott »

shajznnckfke wrote: post #17
Nacdor wrote: post #6

Given the option, would anyone choose to book a trip on one of these new Boeing aircraft rather than anything else? I know I wouldn't, my family wouldn't, and none of the friends or co-workers I've discussed this with would. Something tells me airlines are going to be making it even more difficult to determine which aircraft you'll be flying on when you book a ticket. As far as I know they're not required to tell you…

Even though this model has big design flaws and a relatively bad safety record, the absolute level of risk is still pretty low. I knowingly expose myself to larger risks in my day-to-day life. So I won’t lose any sleep over booking a flight on this type of plane.

I think the difference is that this is a (potentially) higher level of risk for a generic product. You can avoid it by simply avoiding the plane, which will be trivial for some consumers.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#97

Post by labcomputer »

imglorp wrote: post #66
kevin_thibedeau wrote: post #4

They need to implement triple redundant AOA indicators. It's obscene that these failure modes are even possible much less approved. Knowing there is a disagreement just lets you know you are close to being fucked.

Triple is not needed, just double with a redundant "disagree" alarm. Once the pilot knows there's one bad AOA, they can lock out the bad one as an input to the autopilot/MCAS, or hand fly without automation. Of course this is all a bunch of new software and training though.

How do you know which one is bad?

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#98

Post by stefan_ »

stx wrote: post #82
cockpitherald wrote: post #57

This proposed AD would require installing new flight control computer (FCC) software, revising the existing Airplane Flight Manual (AFM) to incorporate new and revised flight crew procedures, installing new MAX display system (MDS) software, changing the horizontal stabilizer trim wire routing installations, completing an angle of attack sensor system test, and performing an operational readiness flight. https://kokp…

Why not include a secondary angle of attack sensor. From what I hear some military aircraft have 4 of them in case of failure. I do understand that the bigger issue was not just that the angle of attack sensor failed but that the crew was not informed of how to handle the failure.

They have two AOA sensors. In a particular stroke of genius, the MCAS system would select one randomly at boot and use it exclusively (so you have twice the failure rate of a single sensor and no benefits from an extra one).

And the AOA disagree system the FAA "proposes" installing? That was already an optional extra.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#99

Post by yborg »

jonathanliu wrote: post #27
cm2187 wrote: post #5

Boeing and the FAA. Feels like an old couple that has to live under the same roof, so it is broken dishes and shouting all day long.

FAA was the battered spouse until Boeing had those two very public crashes. Thanks regulatory capture.

In a way, it's fortunate that the two MAX crashes happened overseas. If they had happened in the US, Boeing could have used its regulatory leverage to cover up the problem for a few more crashes.

Re: U.S. FAA proposes requiring key Boeing 737 MAX design changes

#100

Post by rsynnott »

vkou wrote: post #71
Nacdor wrote: post #6

Given the option, would anyone choose to book a trip on one of these new Boeing aircraft rather than anything else? I know I wouldn't, my family wouldn't, and none of the friends or co-workers I've discussed this with would. Something tells me airlines are going to be making it even more difficult to determine which aircraft you'll be flying on when you book a ticket. As far as I know they're not required to tell you…

> Given the option, would anyone choose to book a trip on one of these new Boeing aircraft rather than anything else? I know I wouldn't, my family wouldn't, and none of the friends or co-workers I've discussed this with would. You wouldn't, but the thing is - you don't get the option. Your airline won't tell you which plane you'll be flying until boarding time. You then have the option of cancelling your flight witho…

Most airlines only use one manufacturer for this size class; it’ll be 737-XXXs, or a32Xs, but rarely both. So just choose an appropriate airline. Not always an option, of course, but on the biggest routes it generally is.
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