But health minister Khairy Jamaluddin gave an assurance the decision followed risk assessments and improvements to ventilation in plane cabins, including the installation of high-efficiency (HEPA) filters in aircraft.
People are still encouraged to keep their masks on in planes if they are in the high-risk category, experience any Covid-19 symptoms or are travelling with high-risk individuals such as children or the elderly.
FMT spoke to AirAsia engineers and cabin crew for a look at how an airline ensures passengers are protected against Covid-19, even when they are not wearing masks.
‘Refreshed’ cabin air
Yap Sheng Lin, a maintenance manager, said cabin air is refreshed every two to three minutes via a process that involves mixing cabin air and pressurised air from outside the aircraft.
This has been normal practice for years but people were only now getting to learn more about this because of the pandemic.
He said when a plane flies at a high altitude, the outside air would be very dry and unsuitable for people to breathe.
Hence, pressurised air from outside is tapped from the engine and sent to a mixing chamber in the cargo compartment for filtration.
Simultaneously, 40% to 60% of air from the cabin is recycled through HEPA filters before being mixed with the pressurised outside air and recirculated into the cabin.
What are HEPA filters?
HEPA filters are the latest equipment installed in planes to remove contaminants and airborne particles. Yap said these filters can remove up to 99.9% of pollutants, ensuring the safety and quality of the recycled air.
“We have two HEPA filters for an Airbus A320 aircraft at the outer front compartments, on the left and right, which are replaced every 5,000 flight hours or whenever a defect is reported.
“All of AirAsia’s aircraft are fitted with these filters,” he said, adding that even if the filters are not defective, they must be replaced according to the maintenance schedule.
Cleaning and disinfection
AirAsia senior cabin crew member Rosita Sulaiman said the crew must ensure the plane is clean and safe before passengers board, and during transits.
This involves wiping each tray, spraying the cabin with disinfectant and vacuuming the cabin floor.
“We are also trained to assist with any medical situation inflight, including identification of those who might feel unwell.”
Yap also said deep cleaning is carried out on every aircraft during night stops, not just in the cabin but also the cockpit.
This disinfection takes two hours and usually involves six cleaners in two teams so as to avoid cross-contamination of bacteria.
Fully-vaccinated pilots and cabin crew
Yap said all AirAsia staff have been fully vaccinated against Covid-19, from its human resources employees, ground staff, cabin crew to pilots.
These are among measures in place to safeguard travellers and put their minds at ease as they travel sans mask.
While masks are no longer mandatory on aircraft in Malaysia, other countries may have their own rules.
More importantly, passengers are advised to take fellow travellers into consideration, practise self-regulation and wear masks if they feel unwell.