Malibuflyer wrote:
Therefore what this topic would really require is a neutral scientific evaluation of how big the problem really is: Not influenced by manufacturers or by people fighting for money…
There are quite a few of these but some have been silenced and others simply decried as not serious e.t.c. If you see how “scientific evaluations” are often enough used in politics that should not surprise anyone. The way I see it from following it from afar but still with interest is that slowly but surely the problem is coming to the attention of people who may just have enough influence to finally get the facts on the table rather than pushing it into corners.
My personal take, as I have written above, maintenance is a huge issue on this. Which is why we have seen much less cases in the past than today, where penny pinching and cut throth economy have lead to whatever shortcut can be taken will be taken. Personally I have been privy to some incidents with older planes no longer in use now which were notorious for APU contamination and more recently some concentrating on some companies who appear to have a problem with this as well with recurring incidents, often involving the same planes. It is also noteworthy that in recent times more crews appear to pay attention and declare such cases more often than maybe before.
In my view, those who claim that all bleed air planes would have to be grounded etc disregard the fact that while the problem has become larger, with proper maintenance AND proper warning systems this may not be the case at all. Nevertheless, the industry is reacting positively in my view by offering newer technology to pressurize cabins (787, A320neo as an option).
Seeing how some deficiencies have been poh-pohed over decades only to come back to haunt those who hid them successfully in this industry now, it would be desirable if the industry finally got working on this before they are told to. There are signs in any case that attitude towards the problem is changing for the better.
Was anyone else mildly amused that supposedly the chap was staying at “Contamines-Montjoie”…. 
Reportedly, a whole Easyjet plane is now suspect, after one guy from Brighton (UK) flew in it. The authorities are releasing very little information “due to privacy rights” of a single passenger who had it.
If the current chinese flu virus goes anything like it looks it might be, many of us won’t be taking airline trips…
How about the current one: the corona virus?
In an airliner, you are breathing viruses from potentially 150+ other people. They are no doubt attenuated somewhat, but…
This for example suggests the problem is not that bad, but it isn’t what an airliner maintenance engineer tell you privately Also the ventilation system doesn’t work properly when on the ground.
And “120” other reasons to fly GA are here
The report mentions at least two kinds of problems: a) metallic particles and b) toxic fumes. I would mention a third one: c) visible fumes.
a) On the metal particles the report itself indicates they are mostly iron, titanium and aluminum, none of which are toxic to the human body, and are only present in infinitely small quantities.
b) On toxic fumes, they are typically related to bearing seal damage letting engine lubricating oil into the airflow. This can be easily and quickly isolated by closing the relevant valves and all transport aircraft are designed to allow the continuation of pressurized flight, sometimes with a restriction to FL250. If such is not the case then improper crew procedures may have been involved. You have to bear in mind human nostrils are very sensitive and we typically get reports way before the defect has any material impact. We then use a high-sensitivity sniffer tool to confirm the source. Most of the times, people can smell it before it reaches any measurable toxicity or leakage levels. In a quarter million flight hours, we once had to remove an engine due to such odour, despite leakage being unmeasurable.
Less typically they can be related to a larger engine engine failure leading to multiple engine materials being driven into the bleed flow. The subsequent engine shutdown closes bleed valves in a second isolating the system and impeding flow into the cabin. These incidents are very scarce.
d) Are more frequent. Some could fall into the b) category. Most are the result of moisture condensation due to faulty water separators in the system or simply firing cold air into a moisture-laden cabin, in some cases spectacular but again as harmless as cold water vapour can be.
Having said the above, I prefer the 787’s outside air systems, even if bearing in mind those electric compressors could also leak some bearing lubricant or rubbing metals into the airstream…
Ah, the good old opening the window trick …works great (mostly in cars) unless the (typically ground-) vehicle in front of you is spitting some combustion byproducts into its slipstream….
This is why, whenever the cowlings are off, it’s important to eyeball the pipework which feeds the ventilation air into the cockpit. Best to not skimp on this, too, even if sometimes (with e.g. Socata using metric-sized tubing made by obscure French manufacturers) it may not be exactly cheap.
@Mooney_driver
It‘s actually hard to judge how big the problem really is. It is quite a small but very vocal community that talks about it and brings it forward.
On the other hand, CAAs and national accident investigators do not see this a s a major risk to safety. Some aspects of this discussions are quite „interesting“ (to say it carefully): E.g. in the case of the Spirit Airline captain that is even claimed to have died by such an event there is extremely broad internet coverage, but not even a serious incident report from the NTSB. Hard to judge who is right.
Therefore what this topic would really require is a neutral scientific evaluation of how big the problem really is: Not influenced by manufacturers or by people fighting for money…
@Snoopy
On long haul crews typically fly less than the real frequent flyers (I don‘t refer to those people getting a silver card because they know how a plane looks like but people like the top factory engineers at the global manufacturers who have to fix complex line problems in Brazil on Monday and in Shenzen on Wednesday…).
On the Frankfurt-Joburg flight e.g. you quite often have someone sitting next to you who takes the morning flight into Joburg and gets back on the evening flight while the crew has to rest for a day…
One 787 pilot told me the cockpit gets fresh air directly from the outside
The 787 is not affected by TCP problems because it doesn’t use engine bleed air for pressurization.
