Well that should take care of the HEPA filter myth

[ozbiggles]

https://www.abc.net.au/news/2020-09-30/covid19-ruby-princess-passengers-infected-qantas-coronavirus/12718748

My thoughts are it probably is a hostile environment for Covid...but it has to get there first. Trying to con people into thinking HEPA filters made an aircraft cabin safer always was a dodgy call.

[compressor stall]

HEPA filters won’t stop COVID going from person to adjacent person. No one has ever seriouslyclaimed that.
What they do stop is COVID recirculating throughout the cabin.

One thing that Airbus’s cabin airflow studies recommend - and I have yet to see on 4 airlines I have paxed on in the last few months (including QF) - is closing the overhead air vents prior to pax boarding. Open they will both 1. Spread particles further and 2. Suck any particles into the airflow down onto the pax.

[ozbiggles]

Didn't they?

https://www.abc.net.au/radio/programs/pm/qantas-claims-of-low-risk-on-planes-disputed/12366380

They were very careful in their wording, trying to create an impression that didn't tell the whole story

[OldLurker]

One thing that Airbus’s cabin airflow studies recommend - and I have yet to see on 4 airlines I have paxed on in the last few months (including QF) - is closing the overhead air vents prior to pax boarding.My experience as SLF in Europe pre-Covid (I haven't flown since March) was that all overhead air vents were routinely closed before boarding, presumably by the cleaners. I noticed that because I always wanted them open! YMMV wherever you are.

[compressor stall]

They were very careful in their wording, trying to create an impression that didn't tell the whole story
yes. Careful words.

However a plane will be safer than a bus or train for the same cabin volume per person. Those forms of mass transit (modern ones not red rattlers!) don’t have the same rate of clean HEPA filtered air coming in.

[Lookleft]

11 people infected with a pax load of 243. If the aircraft environment was conducive to the spread of the virus I would have expected a higher number. I would suggest that the 11 infected possibly got it by being seated close to the infected people plus face masks were not being worn by all pax at that stage.

[Sunfish]

Lookleft, I haven’t kept up with what the airflow models are inside the cabin these days, all I seem to remember is that bleed air cost money, smokers were at the rear and the state of the cabin outflow valves at overhaul was just disgusting. Is it possible that the covid infected cruise passengers were sitting in a spot where there was not much recirculation? Maybe if they were in 1A and B they might have infected a plane load?

[Traffic_Is_Er_Was]

Trying to con people into thinking HEPA filters made an aircraft cabin safer always was a dodgy call.
Yet no cabin crew contracted COVID? Do they not breathe the same air? Do they not move throughout the cabin, thus being much more exposed to multiple zones?
Perhaps the HEPA filters were doing more than you think. I would say the infections were more likely caused by contact transmission, given the number of cruise ship passengers on board, and the small number of non-cruise passengers infected.

[compressor stall]

Sunfish, your first sentence is correct. The rest is highly improbable and not borne out by any evidence - papers or anecdotal - to date.

[Bend alot]

Yet no cabin crew contracted COVID? Do they not breathe the same air? Do they not move throughout the cabin, thus being much more exposed to multiple zones?
Perhaps the HEPA filters were doing more than you think. I would say the infections were more likely caused by contact transmission, given the number of cruise ship passengers on board, and the small number of non-cruise passengers infected.
But cabin crew have contracted COVID 19 on at least 1 other flight.

Most cruise ships had pretty low numbers of COVID 19 on a % & time basis - 2 or 3 notable exceptions.

[Anti Skid On]

Yet no cabin crew contracted COVID? Do they not breathe the same air? Do they not move throughout the cabin, thus being much more exposed to multiple zones?
Perhaps the HEPA filters were doing more than you think. I would say the infections were more likely caused by contact transmission, given the number of cruise ship passengers on board, and the small number of non-cruise passengers infected.
Routine practice in hospitals is for rooms to have a positive pressure; the clean air comes from the top, the dirty air sucked out at the bottom. I am guessing that is why CC are less likely to be infected, as they will routinely be above the faces of pax.

[Ollie Onion]

I thought this was good news, you take a bunch of highly infectious symptomatic passengers and put them on a 5 hour flight with 200 plus other people with NO precautions and only 11 other people pick up the virus, they may have picked it up at the airport in the departure lounge, during boarding or disembarking etc, what it shows is that aircraft are not the incubators in the sky many claimed and with extra cleaning, hand washing, lack of service and mask wearing they probably are extremely low risk environments. That long haul study showed after an 8 hour flight a highly infectious person only infected those sat directly around him, once again this was before precautions were being taken.

[turbantime]

I thought this was good news, you take a bunch of highly infectious symptomatic passengers and put them on a 5 hour flight with 200 plus other people with NO precautions and only 11 other people pick up the virus, they may have picked it up at the airport in the departure lounge, during boarding or disembarking etc, what it shows is that aircraft are not the incubators in the sky many claimed and with extra cleaning, hand washing, lack of service and mask wearing they probably are extremely low risk environments. That long haul study showed after an 8 hour flight a highly infectious person only infected those sat directly around him, once again this was before precautions were being taken.

Precisely what I was thinking. 11 highly infectious pax got on, infected another 11. That could have happened anywhere inside the terminal at both ends rather than the aircraft itself. How does this compare to clusters that appear from pubs/clubs/restaurants? Very favourably I'd imagine. Another thing that get overlooked is that the air is a mix of 50% fresh and 50% re-circulated on an aircraft which equates to all the air being replaced every 2-3 minutes on a narrowbody. How fresh is the air at a gym or while seated indoor at a cafe/restaurant?

Make your own conclusions, those who choose to live in fear will never live.

[TLoraine]

With the increase look at HEPA filters it would be good for the regulators to mandate and regulate their use as opposed to just manufacturer recommended guidelines.