Boeing 787 (lack of) safety claims

[Melburnian1]

It's impossible for mere travellers like me to know whether these claims are factual or grandstanding:

Boeing whistleblower raises doubts over 787 oxygen system

Former quality manager says Boeing was driven by cost and schedules above safety, which it denies.

www.bbc.com

However they are very detailed.

Muckraking, sensationalism or 'on the money?'

What do AFFers with a technical or aviation background think?

 

[oz_mark]

I don't know what the curren situation is, but Qatar were refusing to accept aircraft made in the South Carolina plant.

 

[jb747]

It's impossible for mere travellers like me to know whether these claims are factual or grandstanding:

Boeing whistleblower raises doubts over 787 oxygen system

Former quality manager says Boeing was driven by cost and schedules above safety, which it denies.

www.bbc.com

However they are very detailed.

Muckraking, sensationalism or 'on the money?'

What do AFFers with a technical or aviation background think?

The claims are detailed, but that doesn't mean they're true. On the other hand, the wording of the repudiation by Boeing is suspect as well.

I wasn't aware of it, but a bit of research today would indicate that the 787 has a passenger oxygen system that is different to every other airliner. Up until now, there have been two possible systems. You either have a few very large high pressure oxygen bottles, with plumbing to all of the seats, or you use chemical oxygen generators, with systems installed over every seat. The gaseous systems have the advantage of containing a great amount of oxygen, normally well over an hour. The chemical systems are simpler, but have limited amounts of oxygen, in the region of 10-18 minutes.

The gas systems can be turned off, and can also be reset in flight. The chemical systems are single use. Once a mask is pulled down, they can't be stopped, and must be replaced.

The 787 would appear to be a mix of the two. Basically there are many small oxygen bottles, with each bottle serving 4-6 seats. They are fired pyrotechnically, so once activated, they will need to be physically replaced. They save on plumbing, which probably means a bit of weight. Boeing apparently claimed they'd all been tested...but you can't test pyrotechnics, only the firing circuits.

To be honest, I'm not sure that I like what I read about the system. The old gaseous systems were reliable (there was only ever one failure, amongst untold installations). If accidentally activated, it was no big deal to reset them, and nothing was used up. The 787 system doesn't seem any less complicated, it has reliance upon electrically actuated pyros and accidental activation will be a big event.

 

[Melburnian1]

Thank you jb747 for distilling something that's highly technical down to (mostly) everyday language. Hmmm, I hope government regulators are aware of the issue you raise in the final paragraph.

 

[moa999]

To be honest, I'm not sure that I like what I read about the system. The old gaseous systems were reliable (there was only ever one failure

But far less damage if one of the smaller bottles falls. And with so many bottles on board each 787 the hours flown is now getting pretty high.

From the article it appears that most of the claims have already been investigated and some processes fixed.

would also assume on the failure rate that like most plane systems there is redundancy, so it would be more 3 bottles serving 12-18 people for example.

 

[only4tehlulz]

The 787 system doesn't seem any less complicated, it has reliance upon electrically actuated pyros and accidental activation will be a big event.

Takata v2??

 

[jb747]

But far less damage if one of the smaller bottles falls. And with so many bottles on board each 787 the hours flown is now getting pretty high.

The hours wouldn't even register in comparison with the hours flown by the pressurised systems before one failed. I'm not sure that we understand exactly how the composite fuselage would behave in those circumstances. Fire, especially on the ground is probably the biggest concern, but no more so than the chemical generator systems. And, if people are still in the cabin at the point a fire starts to make them fail, it's already far too late.

From the article it appears that most of the claims have already been investigated and some processes fixed.

Previous systems were simple in that for a gas system, some valves had to be opened. Because multiple bottles are involved, the failure of any valve would have little effect upon the overall system. And because those valves can be closed, nothing is actually used up in actuating the system. Chemical generators need to have a pin physically removed (which is what pulling on the mask does). They don't activate if the masks aren't pulled, so the entire system wouldn't fire for a less than full passenger load. No pyros are involved in either of these systems.

I'm not sure that I have much trust in Boeing these days. No, actually I am sure. I have none.

would also assume on the failure rate that like most plane systems there is redundancy, so it would be more 3 bottles serving 12-18 people for example.

As I understand the system, you basically have one bottle for a block of seats. There is no redundancy within that block, so if the pyro fails to fire, then there would be no supply to them.

 

[Melburnian1]

...I'm not sure that I have much trust in Boeing these days. No, actually I am sure. I have none...

Big statement. Worrying for passengers if those with aviation experience now believe this. Do our other aviators agree?

If this view took hold among aviators (and regulators) it would have ongoing, extremely negative consequences for Boeing. One doesn't want to be alarmist but in a worst case, it could mean the 'death' (or unexpected takeover, continual loss of orders or mass sackings of management) of/by Boeing, and increased market share for Airbus and others (noting that our aviators have not always been complimentary about Airbus initiatives such as 'fly by wire.')

 

[jpp42]

The old gaseous systems were reliable (there was only ever one failure, amongst untold installations). If accidentally activated, it was no big deal to reset them, and nothing was used up.

For those interested in this subject, however, the failure involving QF 30 in 2008 is quite remarkable. See Qantas Flight 30 - Wikipedia . Very lucky that further damage or injury did not result. In general, Qantas has been quite lucky with the serious incidents it has sustained over the years, particularly the period of 1999-2010 (incorporating the Bangkok runway overrun crash in 1999, this oxygen cylinder incident, the A330 loss of control incident also in 2008, and the A380 engine failure at Singapore in 2010).

 

[dajop]

For those interested in this subject, however, the failure involving QF 30 in 2008 is quite remarkable. See Qantas Flight 30 - Wikipedia . Very lucky that further damage or injury did not result.

jb747 does know a fair bit about that particular incident