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Airbus A220 Chief Engineer Explains How Cabin Air is Cleaner Than You Think

When at cruising altitudes, the cabin air is a mix of fresh air drawn from the outside of the aircraft and passed through High-Efficiency-Particulate Arrestors (HEPA) filters ( More...

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Peter Steitz 3
Tell the Chief that planes older than about 5 years don't have those filters. Air is brought in from the engine compressor and is very hot and sterile. It then goes into the air cycle machines and mixed with cabin air to control the temperature. Cabin air will contain all the exhaled carbon dioxide, viruses, microbes, fungi and other human waste. It is vented out the rear bulkhead but the cabin is never 100% pure.
Pat Barry 4
Oh, give me a break. Does this Airbus man really expect us to believe this garbage.
Straight talk : the cabin air comes from bleed air on the engines. The more bleed air that is taken for the cabin, the more horsepower that is lost so, by design, on every rotation of air just 1/3rd is replaced.
He goes through this claptrap of vents at the top and vents in the floor and toilets etc, which is true, but the cabin air is only partially replaced on every rotation and viruses and bacteria get circulated throughout the cabin.
The filters are NOT capable of removing a virus. That is a literal impossibility. Besides, they are changed every thirty days, not after every flight, if a virus was caught in a filter it would still be capable of infection for a time.
The airline joke that if someone in first class sneezes that everyone in economy catches a cold is actually true.
A imagine that this is designed to lull a typical passenger into believing that travel on a Scarebus is safe from Covad19, versus Boeing, perhaps? But I really object to the plain untruth of this article. It is just false. Any aircraft engineer knows this.
Janna Brown 2
Has the CDC or anyone posted incidence of positive COVID-19 cases or outbreaks among flight crews, passengers or particular flights? If you know, please share the source. Many thanks!
Zac Grant 1
The only aviation-related thing I've seen is the TSA's list of infected screeners. This research would be difficult, though, because of the amount of contact with people before, during, and after a flight, especially for flight crews. Pilots and FA's spend their overnights in hotel rooms and restaurants, as well as living in big cities, where one is more likely to catch the virus. Unfortunately, I'm not sure there is any way to tell if you got it on a plane or elsewhere in your interactions while traveling
greg satz 2
The challenge for me is what to believe from sources that benefit from getting us to believe something, in this case HEPA is effective against Covid-19. I know I often get sick from flying which leads me doubt that most air carriers have any ability to protect me from Covid-19. Also a Chief Engineer knows how to use numbers. Citing research or studies that in fact their places are effective would go a long way to helping my confidence. This article doesn't do that and that leaves me wondering about its true intention. I am not in a hurry to be an early adopter of this virus.
Q/ Why not build an intense UV source into the recirculation system?
Fred Bailey 2
Tell the chief to fly his children and grandchildren I’m gonna be driving for my staycations for a while. Coronavirus isn’t even close to being sorted out yet,
Scott Sample 2
Is the HEPA filtering described in this article typical of all aircraft in use today, or in the latest designs only? Am at more at risk in an older 747 than I am in an A321?
Zac Grant 1
not sure, tried googling it, but this is all I could find (from IATA): The majority of modern, large, commercial aircraft, which use a recirculation type of cabin air system, utilise HEPA filters. A small number of older aircraft types have filters with lower efficiencies.
Zac Grant 1
The Centers for Disease Control and Prevention (CDC) explains that airplanes built after 1980 recirculate up to 50 percent of cabin air by combining the internal air with external air, filtering the supply through the HEPA filter. On average, this process occurs every three minutes. Only particles smaller than 0.3 microns manage to pass through the device, meaning that the vast majority of contaminants are completely removed.
markstar426 3
Don’t let facts get in the way of your feelings. Take the train
I did that one year. Where are all the toxic chemicals being shipped? By train. It was very instructive. Yikes...
So, if airlines allowed smoking, the cigarette smell would be contained to the smoker’s row. I doubt it. If someone is sick on the plane, whether they know it or not, whether they have a temperature or not, everyone is at risk. Until we know more about the coronavirus and have decent tests and vaccines, I am not flying.
Peter Steitz 1
Exactly. A passenger lit up once on a no smoking flight and we imminently smelled it in the cockpit.
bobinson66 2
A buddy of mine was an overnight aircraft repair guy for United. Back in the days of smoking, if the flight engineer reported a slow pressure leak, it was likely a door seal. All they had to do was inspect all door seals and look for the "tar" stripe and replace that seal. Now that passengers don't smoke on flights, it's a lot harder to find the seal leak.
Pat Barry 3
Back in that time, the filters would collect tar from the cigarette smoke, and the filters are at the aft of the aircraft. I've seen black tar, dripping off the filters, when they were changed at 30 day intervals. It was like honey dripping off honeycomb. Disgusting.
Smoking was a God given right back then. Nobody was going to take their cigarettes away from them!! Smokers were committed to their privilige, and everyone on the plane choked, It was intense.
I was in business upstairs on a United 74-400 and someone in first class lit up, and we got the smoke upstairs. It was disgusting.
The fact is that, still today, despite the claims of some people who claim to the contrary, only 1/3rd of the cabin air is replaced on a rotation, so the bugs are circulated again and again. Hepa filters cannot hold back a germ or a virus - to do so the filter would be so dense as to require great pressure to force the air through, and that doesn't exist on any aircraft.
This was very informative and should get wider exposure to the general traveling public. The article implied that this applied to all modern airliners, which I hope is the case.
Eric Weis 1
Notice the use of word virus clusters. I would be interested to have specific data on CFM and air exhanges, how quickly clean (?) air is being replenished. Also, this has NO bearing whatsoever on surface contamination. Are lavatories being sanitized after every use? Doubtful. Conclusion - confinement in closed spaces will continue to be risky, until herd immunity and/or efficacious vaccines have been proven. As I have a risk factor (age), I won't fly ANYWHERE for at least a year, if not longer.
Robert Cowling -6
I'm still not comfortable flying. Too many idiots, not enough faith and trust in the air carriers, sorry. They seem to be always trying to think of new ways to gouge passengers, I really tend to doubt their statements of spending time and money 'sterilizing' planes, and such. Once bitten...

And how many airlines are dragging their feet on requiring masks! Yikes...
Thomas Brown 5
That’s why you fly general aviation instead of commercial. You get the best seat, and no TSA or airline crap.
Pat Barry 1
Oh, the United States carriers are promoting their sanitizing, but that doesn't make the difference. They are spraying the cabins at night. I'm sure they pay greater attention to tray tables now.
Te fact is that if someone gets on the plane who has the Covid19 virus, it will be spread in the cabin. That's just the way it is. Remember, this thread started with a man stating that Airbus cleansed the air by entering through the overhead vents and existing out through the floor. That would be great if the air was properly replaced, but it's not.
Your loss pal!
Robert Cowling -7
Whatever. Enjoy being needlessly exposed.
paul gilpin 1
needlessly exposed to what?
west nile flu?
bird flu?
do they make you go through security twice with your Y2K kit?
Pete Schecter 0
very good info, looking forward to our 220's getting delivered late this summer!


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