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Boeing whistleblower raises doubts over 787 oxygen system

bbc.com

151–160 of 223 posts

Re: Boeing whistleblower raises doubts over 787 oxygen system

#151

Earlier quoted context omitted.

My wife surely wouldn’t. The upper deck lav leaked on our heads for half the flight from Sydney to LA. What’s worse than a 16 hour flight? A 16 hour flight where you have to stand in the aisles.

I generally spend most long haul flights standing in the aisle. It's much better for your back and butt.

Have some empathy.

Re: Boeing whistleblower raises doubts over 787 oxygen system

#152
post #146

Earlier quoted context omitted.

You are reading that correctly, but as someone who worked on the system over a decade ago, I bet he didn't have it setup exactly like the plane. I bet he tried to fire all the cylinders at once, a 25% failure rate in this configuration actually isn't bad. But on the actual aircraft they don't fire all of the cylinders at once, they are staged front to back because the power draw is too big to fire all the pyrotechnic…

Reading heavily between the lines now but I would think that this person also had enough (though maybe not as direct) experience to know to stagger the deployment, no?

No. As a quality guy he probably has a lot of experience with the single units, but not the system as a whole. No line inspector would have a reason to test a full ship-set of units off aircraft, so I can't imagine a lab setup to do this test with the proper staging.

Re: Boeing whistleblower raises doubts over 787 oxygen system

#153
post #83

Earlier quoted context omitted.

Was not the problem with MAX in part due to Boeing trying to milk the old design?

More due to airlines demanding a new 737 instead of a new plane. Boeing already made a new 737, it’s called the 757 and nobody bought it.

The 757 was made to replace the 727 and serves a different market segment than the 737.

Re: Boeing whistleblower raises doubts over 787 oxygen system

#154
post #110

Earlier quoted context omitted.

Just last week i heard a story from an older friend about a fighter jet crash investigation he was involved in, where the cause basically was that an engineer wired down some bolts (as required) but trimmed the ends of the wires without recovering the trimmed part. That little piece eventually found its way into the main stick mechanics, causing enough resistance at the wrong moment, preventing the pilot from recover…

This is really interesting to me, how are the crash investigators able to pinpoint the exact cause of failure in such circumstances? I'd imagine a small piece of wire would be just another miniscule piece of debris at a crash site, and unlikely to still be in the location that caused the crash.

Starts with data logging, everything is logged. Then you inspect that area and look for anomalies in the metals in that area. At 5Gs, a little piece of wire becomes a razor blade and leaves evidence. A lot of odd nicks in an avionics bay will lead to testing, interviews and more testing. A worker has no reason to hide details, it would be criminal, so the interviews look at all the possible anomalies and then narrows down to the root cause.

Really amazing work, read NTSB crash reports and they outline the methods used

Re: Boeing whistleblower raises doubts over 787 oxygen system

#155
post #127
post #112

Earlier quoted context omitted.

Do you think the pilot had any idea what happened or did he simply die never knowing?

Its lack of relevance to the matter at hand not withstanding, I admit to be a bit bewildered by your question and thus feel the need to ask: what makes you think the pilot could possibly have any idea that trimmed parts from a bolt is what caused the stick resistance, or that he would spend the time thinking about that instead of recovering the aircraft in the few minutes he had at the most ...

He or she would spend time mentally running through the avionics system to think of what to trouble shoot. Experienced pilots know how their craft works just like you know how to debug a failing drive and not waste time looking at your network cable.

My neighbor is a pilot and I asked him completely off hand how to troubleshoot non responsive flaps and he went into detail about the hydraulics system, where the pumps are and the steps he would take to troubleshoot. This was off the top of his head without a checklist.

Re: Boeing whistleblower raises doubts over 787 oxygen system

#156
post #18

Earlier quoted context omitted.

What I know from how an oxygen generator works, you cannot reliably test those destruction free. So you would have to take some out and trigger them. I would be reluctant to believe that this is the procedure.

The 787 doesn't use generators, they use sealed single use oxygen cylinders. This is a newer version of the 787 system https://www.rockwellcollins.com/Products-and-Services/Commer...

Thanks. However if they are sealed I would assume that you can't test them destruction free, either.

Re: Boeing whistleblower raises doubts over 787 oxygen system

#157
post #83

Earlier quoted context omitted.

Was not the problem with MAX in part due to Boeing trying to milk the old design?

More due to airlines demanding a new 737 instead of a new plane. Boeing already made a new 737, it’s called the 757 and nobody bought it.

It's actually a bit worse than that. American Airlines actually announced the "new" 737 variant before Boeing was even thinking of it[0]. At which point Boeing needed to figure out how to make the next 737 happen.

[0] http://news.aa.com/news/news-details/2011/AMR-Corporation-An...

Re: Boeing whistleblower raises doubts over 787 oxygen system

#158
post #156

Earlier quoted context omitted.

The 787 doesn't use generators, they use sealed single use oxygen cylinders. This is a newer version of the 787 system https://www.rockwellcollins.com/Products-and-Services/Commer...

Thanks. However if they are sealed I would assume that you can't test them destruction free, either.

Yes and no. There is a BIT for each unit, (now I don't know the exact details, but this is how I understand/remember it) but the pyrotechnic devices is tested by running a low level current through it to see if it has been fired/failed. The actual seal is verified via testing prior to aircraft certification, and checked in production using helium.

Re: Boeing whistleblower raises doubts over 787 oxygen system

#159
post #134

Earlier quoted context omitted.

Airbus has similar long-standing issues. On ground / airborne detection logic was broken in 1993 and is still broken in 2019, to a point that it can cause loss of flight controls. Boeing, in contrast, uses simple radar altimeter. Whenever altitude reads 10 feet or less, the aircraft is considered to be "on ground" and things like thrust reversers become available. I personally avoid praising or preferring Airbus when…

Airbus has similar long-standing issues. On ground / airborne detection logic was broken in 1993 and is still broken in 2019, to a point that it can cause loss of flight controls. So you're claiming that Airbus knowingly leaves a critical defect in their planes, which may cause the loss of flight controls and which they refreain from fixing for almost 30 years? Either come up with a reliable source for this statement…

>which may cause the loss of flight controls and which they refreain from fixing for almost 30 years?

And, that as far as we know, hasn't caused

Re: Boeing whistleblower raises doubts over 787 oxygen system

#160
post #135
post #70

Earlier quoted context omitted.

The A380 might actually live the destiny of the 767 or 757. Sure, it was a handful for the manufacturer, luckily pulled it off, kinda broke even after some time. But it will be long gone when it will be really needed, when large hubs become even more congested or certain P2P lines heavily overgrow on themselves.

Good riddance. Despite being so big, its fuel efficiency is unimpressive. Something must be wrong with the design.

Can you expand on that?
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