There are potentially dangerous stowaways on every flight you will ever take. You’ll find them in the first class cabin as well as in economy, sharing your seat, your headrest, even your tray table.

The bacteria that passengers unwittingly carry with them can be a real problem for airline operators. How do they go about getting their aeroplanes truly clean again? And what can we do to avoid picking up an infection when we fly?

Our personal experiences might suggest some operators don’t pay much attention to cleanliness. I once suffered through a long-haul flight – with a stop-over in Miami – in a plane that clearly hadn’t seen a cleaning crew for many days, if not weeks.

“The problem originates with the continuous crowded presence of people,” says James Barbaree, the associate director at the Detection & Food Safety Center, Auburn University in Alabama. “All of us carry microbes on our skin, clothes, and inside our bodies. Some of these microbes are transmitted to other humans, and bacteria multiply in unclean areas.”

Last year, Barbaree and fellow Auburn collaborators published the results of a two-year study, which showed that dangerous bacteria such as MRSA, Escherichia coli and Streptococcus pyogenes can survive for days on surfaces such as armrests, tray tables, window shades, seat-back pockets and the metal knobs and levers in toilets. For example, Babaree’s team showed that the dreaded MRSA bug can survive 168 hours on the material of a seat-back pocket; E. coli O157:H7 – a strain that can cause kidney failure – lived for 96 hours on the armrests.

GPS and elbow grease

The fundamental issue with bacteria on planes is that airlines are struggling to reconcile two conflicting goals. On the one hand they strive to achieve better customer service; on the other hand, they need to boost their profits – by cramming more and more people on board and minimising the time between flights.

Cleaning passenger jets as efficiently as possible involves plenty of planning, staffing, logistics and high priority targets, says Adam Taylor, executive vice president at Air Serv, a company that provides aviation services like cleaning aircraft.

Don’t expect the economy seats themselves to receive much attention

Air Serv takes real time data from its airline customers to establish when planes will land, at which gate, and for how long they will be grounded. It can then co-ordinate that information with the availability of cleaning crews and cleaning equipment. GPS-enabled devices in the equipment helps Air Serv track and monitor the cleaning process, while manual audits keep track of thorough the cleaning teams are and what could be improved.

Other companies have similar systems; Huntleigh USA has a system called E-Clean, which tracks the performance of every member of the cabin cleaning team and gives clients real-time access to cleaning times and the overall quality of the work performed.

Exactly how the aeroplane is cleaned depends on the type of jet, whether it’s a long or short-haul flight, the turnaround time on the ground, the location, and the last time the aircraft received a complete clean. Arrival times, weather conditions and peak periods also play a role, says Taylor. Domestic flights, for example, typically return to the skies fairly quickly – so there’s less time to clean these planes than those used for international flights.

From turn clean to deep clean

Under those circumstances the plane receives a basic “turn clean”. With so little time for cleaning, the team will focus on high priority areas – that means First and Business class cabins rather than economy. Galley areas also get attention, and so do the lavatories. The rest of the plane gets little more than a quick once over – which usually means vacuuming the floor, picking up rubbish and, ideally, wiping the folding tables with an anti-bacterial solution. Don’t expect the economy seats themselves to receive much attention.

When an aircraft is to be parked at an airport overnight, there’s an opportunity for a more thorough clean – a Remain Overnight (RON) clean. Finally, there’s what’s known as a deep clean. That’s when the cabin gets really scrubbed and soaped. It’s typically done on a rotational schedule. “Each airline has specific cleaning procedures and specifications for each cleaning type with the extent of cleaning dependent on the amount of time available,” says Taylor. 

Lufthansa, for example, deep-cleans its jets after approximately 500 hours of flight. At Singapore Airlines, planes get a deep clean once a month – these cleans include technical areas such as air vents. Even nuts and bolts are given a scrub.

When the cleaning crews arrive, they are ready for the specific type of aircraft, ground time and destination. Even so, they always work to a tight schedule. For a quick domestic turnaround flight that may be less than 40 “man minutes”; a larger international turnaround aircraft may get more than five “man hours” of work, says Taylor.

“It usually takes about two hours to clean a Lufthansa A380 with eight cleaners during a typical turnover at Frankfurt Airport,” says a spokesperson for German carrier Lufthansa – depending on how clean the plane was to start with.

The smallest room

Unsurprisingly, toilets are a special focus for cleaning crews. They are small, but used extremely frequently, so they often experience what Taylor euphemistically calls “quality deterioration” during a flight.

But not every airline gives its toilets a thorough clean between each short flight. Some short-hauls can fly two or three legs without being cleaned or emptied, says Lars Barsoe of Vestergaard Company, a firm based in McHenry, Illinois that designs, produces and services airport equipment.

Cleaning methods today are pretty much the same as they were 25 years ago

This can prove to be a false economy. If waste tanks aren’t emptied, the extra weight can result in higher fuel bills. And if they fill completely and the lavatory has to be closed, the flight crew might have to deal with many unhappy passengers.

Some aircraft manufacturers, such as Boeing, have designed their systems to have less so-called “blue water” circulating in the system, which leaves more room for waste. But that sort of efficiency is also “more demanding in terms of cleanliness to avoid unwanted odours,” says Barsoe.

Cleaning and disinfecting the inside of a lavatory requires special products, and usually takes less than 10 minutes per lavatory. The exterior cleaning adds another 10 or 15 minutes: a lavatory truck empties the waste tank and then refills it with clean fluid.  Cleaning methods today are pretty much the same as they were 25 years ago, although the work of the cleaners now can be monitored much more effectively, says Barsoe.

Personal touch

International airline association IATA recommends to its members that toilets should always be kept “totally clean”. In the European Union, domestic airlines have to follow strict regulations for the air and water quality in the cabin. There are also cleaning guidelines from the World Health Organization, although these focus on keeping the plane’s water supply fresh and make recommendations for dealing with health emergencies.

But there are few clear standards for aircraft cleanliness more generally. It is the airline itself that has to establish its own set of standards, says Taylor, which cleaning companies then follow. Barbaree thinks that is simply not good enough: “We need to have more standards regarding the cleanliness of commercial aeroplane cabins. We need to improve our cleaning protocols and rules to minimise the chances for transmission of bacteria and viruses.”

And what can travellers do to minimise our chances of picking up a nasty bug during a flight? An obvious one: wash your hands before leaving the toilet, says Michael Zimring, director of Wilderness and Travel Medicine at Mercy in Baltimore, Maryland. Toilet knobs are a real favourite spot for germs to linger, which can be bad news for passengers who use the lavatory just before a meal. Bring an alcohol-based sanitiser with you – the water inside lavatories is often of questionable cleanliness, says Zimring. And consider using a paper towel to open the bathroom door.

After walking down the aisle, you may want to use alcohol-based soap to wash your hands again, says Zimring – “unless you have perfect balance on the plane and don't have to use the headrests for support going down the aisle”. Sanitiser tissues can be used to wipe down tray tables – particularly given that some passengers have been spotted changing their baby’s nappies on the trays. And finally, don’t forget that one of the best ways to stay healthy on a plane is to stay hydrated by drinking plenty of water, preferably bottled. 

Perhaps we shouldn’t be overly critical of airlines though. At least their planes do get cleaned on a fairly regular basis. The same probably can’t be said of the cars we drive, or the gadgets – including mobile phones – that we use every day. We have to share our world with germs – we could all stand to do a little more to keep the nastiest ones at bay.

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