Originally Posted by
aussiefarmer
I never believed for a second what IATA claimed. Yes modern airliners carry hepa filters that filter 99.97% of virus etc, but sitting in a cramped cattle class seat for 7 hrs (or 17) next to a person shedding virus is a recipe for guarranteed infection - regardless of masks etc.
From there to infecting the whole airplane that’s just plain stupid and physically impossible.
That was mostly about the US Department of Defence. If the US can't safely transport soldiers by air, then they can't invade anywhere. So one has to read their conclusions with caution.
What I can say is that since March I've been on an international across industry COVID safety body, initially looking at the risk of transit passengers in terminals. Since then the scope has changed and increased. Within the company I am trying to make sure that SOPs are adapted to COVID. So I do know more than many.
What I can say is that HEPA filters are pretty effective, but there are other factors.
The three big things are:
1. Community rates in the passengers (quite hard to know) If you are flying between two ports with low rates and few transfer pax, then in theory there is very little risk. NB: Quick tests as part of the security process would really help here, because they do pick up the vast majority of people with a high enough viral load to infect someone. They've managed it in Rome, but clearly there's practical issues.
2. Length of sector, the infection rate greatly increases as sector times increase. The latest I've seen was something like add 3 hours and the risk doubles.
3. Air replacement frequency: In theory cabin air is replaced 10-15 times more frequently than a building at ground level. That means you can be closer to someone with less risk than on the ground. Air replacement frequency actually can vary quite a bit proportionately based on a whole heap of factors.
For crew the risk of catching COVID from pax is lowered by air circulation flowing down. Conversely that increases crew to pax transmission. Masks help but really you need medical grade P2 or higher.
Touch transmission looks to be less of a problem than feared and swab samples haven't found any on cabin surfaces, not that I'm aware of anyway.
So if you're a passenger flying to NZ via DXB from Europe or Africa, then you're facing high community rates and very long sectors, putting you right at the top of the risk range.
I think a big risk for air transport are border rules dampening demand. Health will become a prerequisite to international travel and old school style medical checks (remember when vaccines were an entry requirement for many nations?). Add an expensive fitness tests (e.g. private negative test of x type within y hours - all different of course) and you begin to price people out.