Let's talk about airliner cabin air.

[mn9driver]

I’ve been flying large, pressurized airliners for 38 years. During that time I’ve checked out on a half dozen different types and they all have some things in common regarding the way they handle cabin air.

The first thing is that all the air is tapped from the engine compresser stages. At that point it is extremely hot and guaranteed sterile. It is cooled to a usable temperature and then distributed to the cabin.

In the cabin, the flow of air is mostly from top to bottom. It flows out of ducts above your head next to the skin and flows into return ducts by your feet, also by the skin. From there, it flows to the rear of the airplane under the floor.

At the rear of the plane, in older models it is exhausted overboard. In newer models, about half of it is exhausted and the rest is recirculated after passing through virus-class filters. So, all the air circulating in this way is either sterile to begin with, or has passed through filters that are supposed to be better than any typical face mask.

The one other source of cabin air is from the gasper vents over the seats. These are the small eyeball vents that you can open or close and swivel around if you want. This air is not recirculated. It comes directly from engine packs in its own separate ductwork. It is therefore the most sterile source of air since it is never mixed with recirculated air.

The way the system works, 100 percent of the air in the cabin is changed every two to four minutes, depending on how old the airliner is. Older ones change air faster.

Obviously, sitting close to someone who is coughing or sneezing without a mask is a hazard no matter what. But someone several rows from you is unlikely to give you the virus-at least not in flight. The greater hazard will be during boarding or deplaning.

So, my personal strategy:

-Take a window seat to take advantage of the way cabin air circulates.
-Use the gasper vent to blow sterile air just in front of your face, or to create an air curtain between you and a close neighbor.
-Avoid standing in the aisles during boarding and deplaning.
-Wear a mask as much as possible.

For those of you who will be flying during this time, I hope you find this information helpful.

[BannonsLiver]

1. This is sensible, fact-based advice.

Devoid of emotion, and that's a good thing. I appreciate you posting this.

[leftieNanner]

2. This is great information

My daughter will be flying from LAX to JFK in a few weeks, and I'm very worried. I will pass on your info.

I had heard that most airliners did not have HEPA filters but that some had retrofitted them. Is this true?

[mn9driver]

8. I'm not aware of any US or European airline that doesn't use HEPA class filters.

This has been industry standard practice for years. In older aircraft the filters aren’t really necessary since they don’t recirculate any portion of the air.

[kairos12]

3. Thanks. Great information.

[SaveOurDemocracy]

4. Thanks for this info.

[dhill926]

5. K & R....

thanks for this. I usually fly a lot, haven't since the pandemic, but might have to again. This is vey helpful...

[sorcrow]

6. Thank you

Flying home to Vermont on Saturday from Mexico. I knew about the HEPA filters, but didn't know about air intake and circulation. I feel better about the airborne portion of my travels.

Best regards,
Crow

[octoberlib]

7. I wondered about this. Thanks!

Virologist Dr. Joseph Fair , an MSNBC contributor is currently in the hospital with COVID-19 and he thinks he caught it on a packed flight and not being able to social distance. He had on a mask and gloves but mentioned it can be caught through the eyes.

Link to tweet

Link to tweet

[spinbaby]

10. I'm convinced it's the surfaces

Planes aren’t cleaned between flights, so who knows what’s on those tray tables and armrests. Until recently I’ve flown a lot and picked up bugs only on short domestic flights, not the long-haul flights that started with a clean plane.

[maxsolomon]

22. We always wipe down every plastic surface at our seats with sanitizer

upon seating.

It might help - at least it feels like you're taking action to address the risk!

[cate94]

28. This

We do this too . People look at like we’re nuts, but we’ve been doing it for years now. We bring Clorox wipes for the surfaces and finish with wet ones for our hands. God forbid you have to use a restroom on a flight, but the wet one’s help minimize that risk as well.

[CaptainTruth]

29. I have 3 customers who are pilots & 1 who's a flight attendant.

The flight attendant said what you just said, especially tray tables. She said they're not cleaned between flights & if food is served bits can fall out of people's mouths, or they cough/sneeze on the tray.

She said even before Coronavirus when she flew she carried wipes to wipe down the tray table, arm rests, & seatbelt buckle, to reduce her chances of catching a cold or flu.

[BigmanPigman]

46. I heard that the magazines in the seat pouch

and the plane bathrooms are the worst surfaces to come into contact with. Wear goggles too. I got a pair since I think they may be needed if a stronger, second or third wave comes and there may be a shortage.

[SunSeeker]

57. Good idea. I notice Trump wore goggles at that mask factory.

[BigmanPigman]

70. I did too.

Why are goggles OK for a vain person but not a mask? Maybe after all of those years of bad tanning and make up around the eyes he thinks he already gave the perception of him wearing goggles for years by now and we are used to "goggle eyes".

[oldsoftie]

61. According to the airlines, all planes are being sanitized between flights now.

I have a friend who has a few pre existing conditions; heart surgery being one of them. He has flown every week for work since day one of this. I've looked at him as a guinea pig of sorts. He's said he hasnt had any problems so far. I need to ask him what the most crowded flight was though. I know he's been on several that were sparse.

[enough]

9. Thanks NT

[Voltaire2]

11. If the person 2 inches from you is infected

all the hepa filters and directed air flow aren’t going to help a whole lot.

[stopdiggin]

41. okie doke. then don't fly.

but it's a long old slog driving from Salt Lake to Tallahassee. Ask anyone that does it. But it's your call.

[Voltaire2]

44. I'm not. Nobody else should unless it is unavoidable.

That’s the point. It is not safe.

[BigmanPigman]

47. Only ESSENTIAL flying...like for an emergency,

is what they are suggesting but people are not listening out of choice (selfishness). It is not essential to fly home for Mother's Day or the whatever other excuse you give for endangering yourself and others.

I wouldn't step foot on a plane or in a classroom unless you put a gun to my head since they would have the same outcome....my possible death. Tough decision...you either fly to visit Mom and possibly kill her as well as yourself or you call, skype, send card and flowers (like you have done in the past, I am sure). Real tough decision...

[oldsoftie]

62. Cant remember when i've ever been TWO INCHES from anyone I wasnt being intimate with.

[Voltaire2]

68. so you never sat in steerage on a full plane?

The person next to me: their arm is literally 2 inches or less from my arm. Must be nice to always fly first class.

[oldsoftie]

71. The chances of catching this from an arm is very small.

Far more likely to inhale it than anything else. But yes, the stranger right next to you IS close.
As I posted elsewhere, we're just going to have to get used to paying more for a less populated flight. The airlines have to make a profit & thats the only way it will work without continuing to shove 3 to a row.

I only fly 1st class when i get upgraded. Its SUCH a ripoff price!

[Voltaire2]

72. Actually it isn't. But we digress.

You claimed that no stranger ever sat with 2inches between you and the stranger. That claim would only be true in first class. I can’t imagine why you made that claim when everyone who has flown in coach over the last 30 years or so has experienced the steady shrinking of seat space to where 2 inches is being generous.

Contact is a pretty good way to catch covid. Better yet the person next to you coughs sneezes or talks. If they aren’t wearing a N95 mask fitted correctly then you will be sprayed.

Understand the risks. Fly if you have to but don’t delude yourself that it is safe.

[oldsoftie]

73. Well, its not exactly unsafe. I have a friend who's flown every week with no problems.

And he has several "pre existing conditions". He flies every week for work; many times cross country. Everyone is wearing masks now. He feels secure & i'm using him as my guinea pig.
We havent seen a bunch of stories of planeloads of infections. The Dr in this story SAYS thats where he got it; we really dont know. But even if its true its still isolated. The airlines are learning just like the rest of us.
But hey, thats the beauty of choice; we all can make our own. If people never want to fly again, they'll drive more. And then we'll see more accidents on the roads. People will not stay home forever.

[FM123]

12. Thanks!

[The Velveteen Ocelot]

13. I've always thought the people were more hazardous than the airplanes.

My feet always froze in those old DC-9s.

[Demsrule86]

14. I won't be flying ...will drive.

[matt819]

15. Very helpful

Thanks for taking the time.

[Guilded Lilly]

16. My "teach an old dog new tricks" lesson of the day!...

Thank you for this great information. With your permission I will pass it along.

[mn9driver]

26. Feel free :)

[Marrah_Goodman]

17. my bf flew home this morning

He works for Delta, so he flies for free. There were only a handful of people on the plane, which was nice because he got seated in first class. They are only booking 50% of seats on flights to keep people separated and only 40% in the main cabin.

My daughter flies to VA in a couple days on United. They say they are mostly flying at 50% on planes but there is only a policy of keeping the middle seats empty from what I could see on their website.

Masks seem to be required on all flights and in the airport here in Boston.

[mnhtnbb]

42. United is not promising to leave middle seats empty

There is a photo circulating on line of a United flight several days ago that was cross country. Practically every middle seat filled.

https://www.sfgate.com/travel/article/united-airlines-full-flight-middle-seat-15264194.php

Don't trust the airlines. It's all about $ with them the way it is with most corporations.

[Marrah_Goodman]

43. Ugh.....

I hope her flight isn't like that one.

[BigmanPigman]

48. Yes, this....

https://www.democraticunderground.com/100213421461

"This frighteningly packed flight out of Newark has doctor saying he won't fly again anytime soon
"A San Francisco doctor returning from volunteering at a New York City hospital to help fight the coronavirus says he was forced to endure a packed flight on United Airlines — despite the carrier’s promise to enforce social distancing.

"Dr. Ethan Weiss, a University of California-San Francisco cardiologist, shared a photo Saturday of nearly every seat full on the plane out of Newark Airport in New Jersey.

Weiss said he was traveling with around 25 other nurses and doctors who have been volunteering on the frontlines of Big Apple hospitals for the past few weeks.

"He noted that he previously praised the airline for flying medical workers there for free, but said the nightmare return trip was the “last time I’ll be flying again for a very long time.”

"Just days before flying, he had told ABC7: “I’m scared of getting on the airplane on Saturday. I’ve been taking care of COVID-19 patients for the last two weeks, and I’m more scared of getting on the airplane on Saturday than I’m walking into the hospital.”

https://www.marketwatch.com/story/this-frighteningly-packed-flight-out-of-newark-has-doctor-saying-he-wont-fly-again-anytime-soon-2020-05-10

Ethan Weiss (@ethanjweiss) Tweeted:
I guess @united is relaxing their social distancing policy these days? Every seat full on this 737 https://t.co/rqWeoIUPqL

Link to tweet

?s=20

[llmart]

66. +1

Dr. Joseph Fair's interview that I saw he stated that ticket holders were told the passengers would be "distanced" and when he got on the plane he saw that there was no distancing whatsoever.

So, yes, don't believe what the airlines tells you. This guy was not lying.

[rurallib]

18. marking for later

[Turbineguy]

19. If I may add to this....

The main problem is the low relative humidity of the air and what that does to our airways and sinus passages.

[mn9driver]

25. True, no way to avoid it.

Personally, I try to drink 8 ounces of water during every hour I am flying. I’ve done that for years. Masks make it harder, though.

[rainin]

38. I have to drink, too. Not sure how I'll manage that

[IronLionZion]

20. That's good to know

But people catch viruses while traveling all the time. So the weak spots are probably crowded airport terminals and the various surfaces touched.

[wnylib]

58. Plus the flow of air through the cabin.

Even if the air is "pure" at the point of origin and after going through a filter, there is a period of air flow through the cabin. A cough or sneeze causes some amount of virus to enter the air, where it can remain active for 3 hours.

Carry on bags sit in a rack, touching each other. Passengers touch nearby bags in the process of loading and unloading their own. People touch the arms and backs of the seats as they walk to their own, and as they walk to the bathroom and back. If not with their hands, their clothes brush aginst people and seats as they pass by.

The virus is active on plastic and metal surfaces for 3 days, so any surfaces inside the cabin could have active viruses on them from previous flights up to 3 days before.

If the middle seat is left vacant, there still are not 6 feet between passengers in the same row. And what about the distance between rows ahead and behind you?

Only a really urgent crisis makes air travel worth the risk. (I know that "really urgent crisis" is redundant, but the word "crisis" alone can be too loosely interpreted.)

[Kitchari]

21. K&R n/t

[CaptainTruth]

23. Thank you for sharing! May I tweet this to my followers?

[mn9driver]

24. Of course. Happy to see it shared.

[Canoe52]

27. Then there was that 5 hour flight one time where the guy two rows back sneezed

and coughed the whole trip. I came down with the worst flu or cold of my life.
I might have gotten it somewhere else...who knows.

[LittleGirl]

54. Same happened to me!

I was flying from Phoenix to the midwest to visit my elderly mother. This woman coughed every 50 seconds for 3 hrs and didn't cover her mouth.
I was sick within hours. I had lunch with my Mom and then was in bed in my hotel room for 2 full days before I saw the light of day again.
I was furious!

[Joinfortmill]

30. Thank you very much. I still think I'll stay home.

[DemoTex]

31. Similarly, I have about 20,000 hours piloting such aircraft ..

My fellow aviator, mn9driver (I am DC9 type rated), gives good advice. The airlines can also help by reducing seating density, short-term and long-term. Some already are doing this by blocking center seat assignments on boarding passes. However, governments and manufacturers might have to get in the act, too.

I'll add - FWIW - that in my decades of flying, I never got sick that I could attribute to exposure through the aircraft environmental system, or exposure to passengers or other crew members. Not even in the days of cigarette smoke in airplane cabins. But - as always - your mileage may vary.

[llmart]

67. As an aside, are you old enough to remember...

when the stewardesses passed out free cigarettes? Yes, they actually did that at one time.

On another note, I would love to see them go back to the days when we all weren't crammed in like sardines in a tin. Maybe this will force them to. Plus, TSA needs to stop making people take their shoes off because of ONE incident with a shoe bomber.

[certainot]

32. beauty, thanks

[plimsoll]

33. 787s do not use bleed air for circulation.

That may become more of a trend, and newer airliners have excellent filtration. The problem won't be the flight itself. It will be when you deplane, or board, go through customs, pass through airport security. Those places will continue to have low ventilation, stagnant air.

[bluecollar2]

34. As a retired airline mechanic

I appreciate your concise description of the cabin air circulation process.

Nicely done skipper.

[malaise]

35. Great post

Rec

[trof]

36. From a long retired TWA driver, thank you.

[Jopin Klobe]

37. All well and good ...

... if the airlines change the filters regularly and keep with the protocols ...

... surely they wouldn't endanger people to save money ...

[oldsoftie]

63. The long term is going to be higher fares & fewer passengers per flight.

Its really the only way it will work for both people and airlines. We want to feel safer & they have to make money, so thats where the compromise will have to be. Flights have been cheap for years now anyway, so not much of a surprise for a raise.

[rainin]

39. Tight fitting goggles, too. Eyes are a point of entry

[Warpy]

40. Thank you!

I never knew the air pattern, although I did know where some of it came from and that some was recirculated. It explains why I've never gotten ill from flying and it also explains why that first airplane full of travelers from China who flew with a symptomatic patient never developed the illness.

This is very useful.

[Karadeniz]

45. Thanks for sharing...this is so helpful...I've never known how it worked!

[tiptonic]

49. Many hours on planes

In my working days (for a air carrier), i spent way too many hours, on those airborne tin cans. Ur description is the by far, the best I have heard, on how the air circulates. Moved a lot of animals, so that subject came up a lot, from our clients. Thankyou..

[McCamy Taylor]

50. Hazmat suits.

[GeoWilliam750]

51. Thank you for posting

[GETPLANING]

52. Three years ago, I almost died of the flu

after sitting in the back of a full flight from Detroit to Houston. The air in the cabin was humid and heavy. I appreciate your post and don't dispute the facts of your post. But when 300 people are packed together like animals in a wildlife market, as they are on today's passenger aircraft, germs are going to be transmitted.

[napi21]

53. Thanks for the accurte info for a change. I can't count the times I've had to explain that to

people who arew convinced that the air in a plane is just recirculated for the whole flight. My son works as an aircraft maintenance tech for one of the remaining major airlines. Has been there for 25 years. I asked him about that when so many people were telling me they hate to fly because they fear getting sick from something a passenger had that got in the darn recirculated air. He explained it all to me and confirmed that any planes that didn't have new filtering were retrofitted, but none of them are in their fleet anymore.

[oldsoftie]

74. ALL of my friends think that. I never knew the extent of the filtering myself.

And you cant tell them otherwise.

[Grasswire2]

55. NBC infectious diseases MD expert in hospital now w/C19 - blames it on flying crowded plane to NOLA.

He was just featured tonight. I think he is in about his fifth day of the illness. 42 years old and healthy.

Catch the replay if you can.

[Niagara]

56. +1000 Dr. Joseph Fair on The 11th Hour from his hospital bed

[oldsoftie]

60. NEVER knew that about the eyeball vents! I wouldve thought the opposite.

[GreenEyedLefty]

64. Great info

I assume all this happens when the cabin is pressurized, not during boarding and deplaning, taxiing, etc.

Nevertheless I'd just as soon avoid being in close proximity to other people, especially given the enormous number of asymptomatic carriers.

[AnotherMother4Peace]

65. Joseph Fair, virologist and epidemiologist, believes he got it through his eyes while on a flight.

Dr. Fair, who has worked safely on recent pandemics, said this one "got him". He took recommended precautions and believes covid-19 entered his body through his eyes while on a flight to New Orleans. He began experiencing symptoms 3 days later. Dr. Fair said "if it can take me down, it can take anyone."

Dr. Fair specializes in emerging diseases, globally. He is also a contributor to NBC and the Today Show.

https://www.nbcnews.com/news/us-news/virologist-hospitalized-coronavirus-believes-he-got-it-through-his-eyes-n1206956

[BobTheSubgenius]

69. What a useful and nifty PSA!

Thank you! My wife is so bummed about not being able to go home to WNY for the summer, as is her usual MO. She is also very leery about getting sick, so this will help her feel better about her trip.

Thanks again....