Covid in cabins: Low risk, no silver bullet

By Bryan Corliss

Oct. 14, 2020, © Leeham News: Covid-19 has made airlines, aerospace companies and suppliers really, really sick. IATA now says it could be 2024 before worldwide travel numbers get back to something near pre-Covid levels.

To get more paying flyers back in the air sooner, the industry is looking for ways to make passengers feel more assured that they won’t get infected while in the air. It’s leading to some innovative solutions and what some industry insiders say is the setting of long-overdue standards for in-flight cleanliness.

Boeing hand-held UV light. Photo: Boeing.

Boeing developed a system using UV-C radiation to sterilize cabin surfaces. One of Boeing’s best-known suppliers, Teague, designed new gaspers to inhibit the spread of airborne virus particles. And several other suppliers are pushing forward with products that inhibit the growth – and potentially kill – viruses and other microorganisms on high-touch cabin surfaces.

Aerospace suppliers say there’s not one silver bullet that’s going to prevent the spread of Covid-19 on jets.

“Buying our material doesn’t magically make your aircraft clean,” said Mathew Nicholls, the sales director for Tapis Corp., which provides virus-resistant fabric imbedded with silver ion strands for seat covers.”

“It’s the sum of all the parts,” he said in an interview for the current edition of Northwest Aerospace News magazine. “The HEPA filters, the airflow exchange. And now we’ve added this, this and this.”

Latest developments

IATA hosted a conference on the subject of Covid cleanliness last week. Airbus, Boeing and Embraer were among the presenters, and some of the key takeaways were:

  • Thanks to air flows in cabins, the risk of Covid-19 transmission when seated on an aircraft is low – even if the person sitting next to you is infected. If everyone is wearing a standard cloth mask, the risk of you inhaling enough aerosolized virus particles to get infected is – not zero – but very low.
  • The odds of getting infected by touching a virus-covered surface likewise are low – again, not zero, but low. So far, there hasn’t been a documented case of someone contracting coronavirus through touching an infected surface, but the risk cannot be excluded. Disinfecting cabins may be more important to reassuring passengers than stopping Covid-19 spread.
  • Some seating companies have proposed shields between seats. Those concepts get a hard no from the OEMs, who note that the shields provide minimal health benefits while disrupting the carefully crafted cabin airflows, which are far more important to minimizing Covid-19 transmission. The shields also would interfere with emergency evacuations.
  • The riskiest part of a flight, in terms of Covid transmission, is boarding and deplaning, when passengers are standing packed together and there is no cabin airflow and an individual’s main protection is that the process is quick enough to prevent them from inhaling enough virus to become infected. Airlines can – and must – do more to enforce social distancing at these times.
Check my flow

Given the emphasis on preventing airborne spread of the virus, an early proposal from Teague, the Seattle-based design company, seems to be more important than ever.

Teague Air Shield. Photo: Teague.

Teague in March released plans for what it calls the Air Shield. It’s an attachment that replaces the valve on standard gaspers to provide a sharp blade of air that surrounds each passenger in their seat.

The air moves fast enough to greatly inhibit the spread of any virus particles that may be exhaled by a passenger, pushing them down to the floor where they’re sucked into a jet’s existing air circulation system, where 99.9% of them are scrubbed out by hospital-grade HEPA filters within two or three minutes.

Teague has done computer modeling on the way the air flows inside a cabin, and set up simulated A320 and 737 interiors for simulator tests that confirmed what the computer models predicted.

One of the biggest benefits to airlines, said Anthony Harcup, Teague’s senior director for airline experience, is that the product is cheap and simple to install.

“A decent, Tier-1 airline using their own ground staff could do three or four (planes) overnight,” he said. “Airlines are really on their knees. They need to have something that they can fit quickly and buy in volume.”

Radiation treatment

Back in April, President Trump infamously proposed injecting bleach into humans to fight coronavirus (a treatment his doctors seem not to have thought of when he himself became infected). He was mocked for that, as well as for saying that light could kill the virus.

But he wasn’t entirely wrong. UV-C radiation does in fact kill viruses and other microorganisms, and it’s been used for decades to sterilize medical equipment. However, its effects on human tissue – rapid and severe sunburn, damage to corneas and skin cancer with repeated exposure – make it impractical for use on humans.

Honeywell cabin robot. Photo: Qatar Airways.

Several proposals have been developed to safely utilize UV radiation on aircraft, however.

Honeywell, for example, has developed a UV-C unit the size of a beverage cart, with arms that extend over seats. It claims it can disinfect a cabin in as little as 10 minutes. Qatar Airways is the first airline to use it.

Boeing in September licensed a UV-C emitting wand it had developed to Florida-based Healthe Inc., which will manufacture the units. Boeing says ground crews can use them to disinfect high-touch cabin surfaces and said that it takes about 15 minutes to completely sterilize a flight deck.

Waypoint developed a cabin lighting system.

And Waypoint Aeronautical in Everett has developed a UV lighting system that integrates into the Passenger Service Unit. The UV lights would be installed in the reading lights. Since they’re limited to a light spectrum (405 nanometers) just outside the UV spectrum, they would not be harmful to humans,  CEO Robert Olson said.

At this level, an airline can keep the system running and disinfecting surfaces while passengers are on board, or put it on a timer to turn and off automatically. Waypoint was developing the system to combat flu infections – following procedures used to battled the H1N1 virus back in 2009 — when Covid-19 hit

Waypoint has made presentations to a few US airlines, but as yet has no takers. Olson acknowledged the challenges of convincing the industry on Waypoint’s solution. “I’m selling something you can’t see killing something you can’t see.”

Bright lights cause heavy damage

There are some real benefits to sterilizing with UV-C, compared to disinfecting with sprays and wipes, said Molly Bridger, the vice president of marketing for Simona Boltaron.

Plastic surfaces can have textures, grooves or scratches where microbes can hide from a disinfectant, she explained. UV-C light, on the other hand, can get into those hard-to-reach areas.

The problem, for airlines, is that UV-C radiation is harsh and that most plastics will fade or otherwise degrade when exposed to it repeatedly. Bridger’s company, which makes sidewalls, side panels and lavatory components, produces a proprietary color-fast plastic that won’t fade under UV-C disinfecting and will also stand up to chemical cleansers.

Part of the solution

A study released last week by Harvard University determined that contaminated surfaces contributed less than 10% of the total infection risk for fliers.

But disinfecting surfaces still should be part of a multi-faceted approach to cabin hygiene including masks, hand-washing, advanced air filters and screening for people showing Covid symptoms, the researchers said.

Several companies are working on materials for high-touch surfaces that naturally resist microbes.

“You’re not eliminating cleaning,” said Ben Smalley, the aviation business manager at Sekisui Kydex. “You still need to clean. But what you’re doing is keeping it clean between cleanings.”

Smalley’s company is the U.S. subsidiary of a Japanese industrial giant. It provides anti-microbial sheets to higher-tier suppliers that thermoform them into finished pieces.

Another company, Nycote, has a nylon-based polymer resin that has been used for decades to stop the growth of microbes inside fuel tanks. Now it’s looking for partners to put the resin on high-touch cabin fixtures, said Andrew Larsen, Nycote’s officer for business development, technical sales and communications. “Seat backs, table trays, arm rests, call lights –anything that we can coat.”

And Tapis markets fabric embedded with strands of a silver ion that’s proven to inhibit the growth of bacteria and viruses other than Covid-19. The company – like most of the other suppliers — is waiting on results of testing against the coronavirus.

What does clean really mean?

The silver lining in all these dark clouds could be that the industry is coming together for what Smalley called a long-overdue discussion on aircraft cabin hygiene.

The Red Cabin group, which specializes in industry meetings for the aerospace and automotive industries, has formed a cabin hygiene working group that is holding virtual meetings on a regular basis to address pandemic-related issues.

One of the first steps, Smalley said, is setting standards for what actually constitutes adequate disinfection.

In an industry dominated by regulatory standards, “nobody has a definition of ‘clean,’” he said. “There really isn’t a standard for clean out there in the industry. People have different procedures, but there isn’t a standard that we’re all striving for.”

That will change as a result of the Covid crisis, Smalley predicted. “That neglect toward aircraft cleanliness in the past is going to be top-of-mind for the industry as a whole. It’s going to be a key part of the passenger experience in the future.”

Preparing for the next pandemic

In its October edition, Northwest Aerospace News reported that several suppliers had found ready buyers for their clean-cabin products.

But given the financial constraints that the airlines face – particularly in the United States, where it seems that no additional coronavirus relief is coming until after the Nov. 3 elections – most buyers are being very selective about their spending, the companies said.

Their message is “we don’t need a knee-jerk fix,” said Nicholls, at Tapis. “’We don’t want to spend a million bucks and have it be obsolete in 12 months; we’d rather spend two million and have it last for 10 years.”

Bjorn Fehrm and Scott Hamilton contributed to this report.

39 Comments on “Covid in cabins: Low risk, no silver bullet

  1. This strikes me as fussing.
    If surface cleanliness is such an issue, why hasn’t the airline industry been consistently plagued in the past by noroviruses, rotaviruses, hepatitis, etc., which are spread by a fecal-oral route, and can survive for a long time on surfaces?
    Also: what’s the point in having a squeaky-clean aircraft if the airport itself isn’t also squeaky-clean? Not to mention the train/cab that brought passengers to the airport to start off with. Passengers bring contamination on board with them, and start touching all sorts of surfaces the moment they board.
    No amount of pre-cleaning is going to prevent contamination…and planes are already generally very clean compared to other modes of transport. Much more important for each passenger to have a small bottle of hand cleanser and a pack of hygienic wipes with him/her, to maintain hygiene during the flight.

    • Clearly if you are saying airplanes are clean compared to other forms of transportation you are sadly wrong.
      Clearly you need to fly filthy airlines like Air Canada. They are now cleaning the 20% of their planes they fly today, however they are not even remotely close to the standards of let pick Cathay pre pandemic.

    • @Bryce

      Yes, and airlines are broke as the article says, so are not going to buy nothing anyway, especially given the recent what me worry report discussed in this space a few days ago, 44? transmissions out of 1.2B pax

      Everyone everywhere is praying for a vaccine, presumably airline execs are as well, why spend now when tomorrow a miracle will cure

      Squeaky clean was required before, as in clean up ind ag, to prevent the manufacture of this and the other viruses

      The logic limit of the clean plane is – we have airplane clean tech, problem solved – but not clean everywhere else, home, airport, office, factory etc is dangerous and cleanup is not going to happen – why is a very small very local solution to a general problem going to make any difference, except by throwing more money at the wrong problem, unless it is to scare the Gvmt into squirting even more bail outs

      Result – we can solve one or two tiny hazards thrown up by the major condition, but we can not discuss the major condition for fear of having to think about what that might mean

    • Pre flight testing by itself is taking a part out of the system then see it fail.

      I had to be pre flight, then post flight (5 days) as well as the mask precautions and spacing out on board and un-board.

      We just saw the poster child of how not to do it from the WH.

    • I agree that the scenarios presented by IATA are rather theoretical.
      For one: the fact that the overhead personal air vents have an adjustable direction means that a sideways motional component can be created in the air flow.
      Second: People walk around the cabin, twist and turn in their seats, move arms up and down (to screens, light switches, vents)…all of which creates localized turbulence patches in the airflow.

      There’s actually a very simple verification of this. Even when seated several rows away from the galley, I can still smell when meals are in the oven. The same applies to odors escaping from the lavatories when the doors open…or to a passenger who’s doing some covert farting 5 rows away. Those odors are carried on air currents, so there is definitely a longitudinal/lateral airflow component within the cabin…no matter how slight.

      But I still think it’s a LOT safer than a subway or bus.

      • >There’s actually a very simple verification of this.
        I don’t think the situations are completely analagous. Covid-19 transmission seems to primarily involve the physical transport of droplets. Odors due to gasses can move through still air via diffusion and quite quickly at that.

        • Keesje’s comment related to airflow…it didn’t mention CoViD transmission.
          Neither did mine.

          Apart from that: I don’t buy the diffusion argument. If the downward airflow is as fabulous as is being claimed, then diffusion wouldn’t have much of a chance.

          • Hi Bryce, the context of the entire discussion is Covid, but putting that aside the point is you can smell things that are “down-wind” if the diffusion speed exceeds the airspeed. Diffusion speeds are on the order of a few m/s for many organic compounds so it is not implausible that you can smell the galley despite being upwind from it.

          • Hi Jbeeko, I wouln’t advise testing that hypothesis to check if a black bear mother with cubs can still smell/hear you coming when you’re downwind from her.
            As regards the thrust of the discussion being about CoViD: I agree with you. But if keesje makes a pure fluidics comment, then a reply therto can also be of a pure fluidics nature.

          • Jbeeko is right, the mechanisms of diffusion and convection are wholly different. Even strong convection does not stop diffusion, and diffusion still occurs even in the absence of convection.

            It’s analogous to the conduction of heat vs the convection of heat. Or humidity. But the droplets in question here are large & heavy enough that they don’t diffuse well, they are not driven by a concentration gradient.

            The primary transport method is convection, and we know from the evidence that cabin convection does not support significant transference of viral load, when masks are used.

          • Aerosols diffuse as a result of their Brownian motion: so if cooking smells from the galley are diffusing through the cabin, then aerosols are also. There may be a difference in particle size and range, but the effect is not zero.
            Although it SEEMS that transmission of CoViD MAY predominantly be due to propagation of macroscopic droplets, there are plenty of dissenting expert opinions that posit that infection may also occur via aerosols. Sure, an aerosol contains a lower dose, but sitting in a plane for 10 hours may still be enough to accumulate a sufficient inoculum. And contrary to what some people here are “confidently” asserting, there is currently VERY little information on the size/duration of the inoculum required to produce (different gradations of) CoViD.

          • The point was that diffusion of odors is not related to. or an indicator of, the spread of COVID, even via aerosols. The processes are fundamentally different.

            Note that odors are still detectable as they are small enough to easily pass through masks, and they also diffuse easily in air. Neither is true for viruses, even in aerosol form, as the particles are significantly larger.

            If you combine the small contribution of diffusion, with the large contribution of convection in an aircraft cabin, and the wearing of protective masks by both infected and uninfected, you get the results that have been experimentally observed, that the transmission rate is low in an aircraft cabin.

          • That may have been YOUR point.
            MY reaction to keesje’s comment was concerned with the evidence of non-laminar flow in the air movements in a cabin, coupled with a vertical flow rate that is insufficient to prevent long-distance lateral propagation of odors through the cabin. I was agreeing with his assertion that the air flow patterns presented by IATA/airlines are highly idealistic.

        • Indeed. There’s mist, vapour, and gas – I consider those different physically.

          With SARS-CoV-2, there is concern about midst but much less than about droplets. Besides movement and filtering, I gather the big distinction is amount of contagious substance.

          There is concern about ‘viral load’ on people regularly exposed – adding up of exposure, such as health care workers, I don’t have much understanding of that.

    • The critical event is the transfer of viral load from one person to another, sufficient to cause infection. If people are masked in an aircraft with the design airflow, there is not enough load transferred for infection. This is confirmed by droplet dispersion testing and is also evident in the statistical data for infection rates on aircraft.

      The misconception that occurs, is that infection can occur from any exposure whatsoever. The truth is that we are all exposed to multiple pathogens every day, even in drinking water, which still has small but measurable levels of pathogens. Good sanitation does not mean zero exposure, it means exposure at levels that won’t make us ill.

      Similarly we have exposure to toxic chemicals and radiation every day, but at dosages which don’t make us ill. We all carry a pathogen load around with us, wherever we go, but our bodies have evolved to live in groups within this environment, and tolerate it quite well.

      Recently there was a report that COVID survives for up to 28 days on surfaces. Without context, that headline will scare the hell out of people. What either isn’t mentioned, or buried in the article, is that it doesn’t exist in sufficient numbers or potency to cause infection.

      Similarly, turbulence in aircraft airflow patterns, or dispersion of aromas, does not translate to infection rates, for properly masked individuals. Your sense of smell is quite acute, it detects levels far below what is needed for the virus to infect you. And turbulence provides dilution as well as transfer.

      This is also borne out in studies of healthcare workers in hospital ICU’s with multiple extremely contagious COVID patients, who spread the virus through breathing and exposure to bodily fluids. With proper PPE, the infection rate is very low, and has improved over time as we’ve learned more about the virus.

      The infection rate occurs in unprotected scenarios with lack of airflow and close proximity, such that there is opportunity for sufficient viral load transfer. Healthcare officials have been saying this for months. But we still have people who don’t fear the right things, and others who fear the wrong things.

      And so we have two calamities at once, persistent infection rates and suppression of economic activity. Both are manageable, but only if we learn properly from experience and research.

      • A couple of terms needed.

        Droplets are the larger size close up ones that are the prime spreader (and are in affect at closer distances).

        The small particles (aeroislized particles) do go further, but the load is lower. Its felt those can infect someone, but the exposure has to be longer as well.

        Egro, smelling fish in a microwave or popcorn (you better share) is not the same as Covd spread.

        • I think that masks should primarily be regarded as a means of reducing outflux of droplets/aerosols….although they probably also mitigate influx.

          Don’t forget that inward infection can also occur via the conjunctiva (eyes). In that regard, hats off to Qatar Airways for mandating use of visors.

          Also: no matter how small the exposure to aerosols, sitting in them for 10-15 hours during a longhaul flught is not a very encouraging idea.

          But sitting on a train or bus for 4 hours is probably even worse.

        • TW, thanks for trying to bring attention

          But the term ‘aerosol’ is used variably. Supposedly there is a formal definition but …

          To me it means between droplets and mist.

      • While bad stuff is always around, individual susceptibility is key. Healthy people occasionally get infected by a tree fungus on Vancouver Island, or flesh-eating disease. I had a significant infection of finger

        (That was an exercise in rushed sloppy medicine, first doctor prescribed an antibiotic that didn’t work much (hey, five days is often not enough), substitute doctor prescribed better but in draining blister went overboard by numbing entire finger – when pus started to build up again before the antibiotic stopped activity I lanced myself with sterilized blade.)

  2. >Airlines can – and must – do more to enforce social distancing
    >at these times. [planing/deplaning]

    A comparison; Oct 10th weekend I flew AirTransat east and AirCanada back. AirTransat had very good discipline, boarding was back to front and when deplaning passengers were instructed (and reminded) to remain seated until the row before them had emptied. Compliance was near 100% and it did not feel slower.

    AirCanada still used a zone boarding system where my “bad” zone had me go to the back late in the process. When deplaning they made no attempt to control things and it was the usual deplaning crowd.

    Based on that there seems airlines have not excuse not to control crowding at those critical times.

    • Inexcusable that Air Canada was doing this so sloppily!
      IATA should issue strict guidelines for these processes, and they should be enforced by airports.

  3. Returning to the ever-popular subject of post-CoViD immunity — and the attendant idea of (limited-term) immunity passports — articles such as this are reinforcing the idea that, after recovering from CoViD, a hell of a lot of people have at least 3 — and even 5-7 — months in which they could travel without posing a CoViD infection-risk at their destination.

    The CDC is similarly indicating an immunity window of at least 3 months:

    All that potential tourism/turnover just waiting to be exploited…and nobody is seizing the opportunity.

  4. I’m all for this. Airlines, manufacturers and regulators can figure out what’s working best, but let’s be proactive.

    Just to say, I’ve carried alcohol spray on airplanes for years, after getting colds regularly on long airplane trips. I spray the tray-table and high-touch surfaces as soon as I get into my seat, and spray my hands before eating.

    For even longer, I’ve avoided shaking hands when I have a cold.

    I also spray my hands after getting off Metro trains.

    I’m not particularly compulsive in general. I think of this as working the odds, which seemed to be Bryan’s whole point in writing the article.

  5. There is no zero risk in anything.

    Getting into a car and driving is a risk that is many magnitudes higher than other risk but people think nothing of it.

    • Absolutely.
      CoViD seems to have caused a manic need to achieve a level of risk-free existence that simply doesn’t exist.

    • Indeed thankyou.

      And Darwin Candidates deliberately drive dangerously, or dash across a highway at night.

      Two cases in BC recently of a motorcyclists zooming past lines of cars, in one case fatally stopped by a barrier (perhaps a road edge constrainer that had been pushed out of line), the other case sounded similar. (In the first case, the constrainers on the outside of the highway are usually there to keep vehicles from going over a cliff, concrete trapezoids as commonly used between opposite directions.)

  6. A key weak point in the airline boarding process was mentioned but glossed over: the loading bridge. My experience at ATL at Southwest is that the agent hurried the “separated” groups so that crowding occurred before we could enter the aircraft. Simple solution folks: hold the next group until the gate agent receives an “all-clear” from the cabin that the loading bridge can be “refilled”. How about starting this tomorrow!

    • “The testing assumed only one infected person on the plane and did not simulate the effects of passenger movement around the cabin.”

      • One infected person was simulated to determine the surrounding radius and concentration for dispersion of the virus. Those results can be used to project additional infected persons, in numerical modeling. When that was done, there wasn’t seen to be a substantial risk of infection. That is also borne out by statistical data.

        They did not simulate the impact of an infected person getting up and walking around, or lowering their mask for eating or drinking. Those would undoubtedly increase the risk. But the overall risk is low enough that this would not be significant as a rational for denying the validity of the conclusion.

        The airflow conditions in airline cabins are sufficient to prevent transfer of an infectious viral load, under normal flight conditions. That has been the contention from the beginning. and there is as yet no evidence to the contrary, but now there is supporting scientific evidence.

        It’s important to recognize that expressing doubts about the method or the results, is not the same as providing evidence. The authors said that more testing is needed and that will likely happen. But my guess is it will substantiate what has been found already, as every existing result also has.

  7. CDC


    FYI from

    Volume 26, Number 11—November 2020
    Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 During Long Flight


    “To assess the role of in-flight transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we investigated a cluster of cases among passengers on a 10-hour commercial flight. Affected persons were passengers, crew, and their close contacts. We traced 217 passengers and crew to their final destinations and interviewed, tested, and quarantined them. Among the 16 persons in whom SARS-CoV-2 infection was detected, 12 (75%) were passengers seated in business class along with the only symptomatic person (attack rate 62%). Seating proximity was strongly associated with increased infection risk (risk ratio 7.3, 95% CI 1.2–46.2). We found no strong evidence supporting alternative transmission scenarios. In-flight transmission that probably originated from 1 symptomatic passenger caused a large cluster of cases during a long flight. Guidelines for preventing SARS-CoV-2 infection among air passengers should consider individual passengers’ risk for infection, the number of passengers traveling, and flight duration.”

    The authors opine:

    “Although the international flight industry has judged the risk for in-flight transmission to be very low (7), long flights in particular have become a matter of increasing concern as many countries have started lifting flight restrictions despite ongoing SARS-CoV-2 transmission (8).”


    • This report was from Vietnam, for a flight that occurred on March 2 2020. at which point no COVID precautions were taken. It’s one of the flights listed in Bjorn’s Corner article data from last week (London-Hanoi), so is part of the 44 confirmed cases. It’s already been included in the analysis and doesn’t change the conclusion.

      This was a 10 hour flight, with 1 unmasked symptomatic primary in business class resulting in 12 secondaries, and 1 flight attendant being exposed and possibly moving the exposure into economy class for 2 more secondaries. So total of 16 people involved out of 217 on the flight.

      Of the business class secondaries, 11 of the 12 were seated within 2 meters of the symptomatic primary. For the economy class secondaries, the 2 people sitting between them were untraceable, so could have been either additional primaries or additional secondaries. They were dropped from consideration.

  8. Love it. Transmission is neither by air, nor by touching. That leaves food and water. And telepathy

  9. Bryce: bears have very good smell ability.

    Polar bears show up on airports and of course housing areas, they even get into food freezers in verandas.

    (Looks like a Beech 99, view foreshortened by long view from camera.
    I can’t identify the airline’s tail logo.
    Looks real – footprints in slush.
    Surface looks paved.
    Many airports are near polar bears, Barrow (Wiley Posts), Churchill, and Iqualuit (Frobisher Bay) for example. They come off of the ice, or at Churchill when ice has melted in the big bay as it long has in summer. Usually scrounging more food, but Barrow had two younguns playing in snowbanks.)

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