United Airlines announced that the carrier will now maximize air flow volume for all mainline aircraft high-efficiency particulate air (HEPA) filtration systems during the entire boarding and deplaning process, helping further reduce the spread of COVID-19.

In combination with the HEPA filters, the air conditioning and pressurization system onboard United's mainline aircraft recirculates the air every 2-3 minutes and removes 99.97% of particles - including viruses and bacteria during both ground and air operations - making the air onboard a plane significantly cleaner than what people typically experience in restaurants, grocery stores, schools or even some hospitals.

designed to minimize transmission

We expect that air travel is not likely to get back to normal until we're closer to a widely administered vaccine"

United pilots and ground staff are working to implement this new procedure for mainline aircraft beginning July 27. "We know the environment on an aircraft is safe and because the air flow is designed to minimize the transmission of disease, the earlier we maximize air flow over our HEPA filtration system, the better for our crew and our customers," said Scott Kirby, United's Chief Executive Officer.

"The quality of the air, combined with a strict mask policy and regularly disinfected surfaces, are the building blocks towards preventing the spread of COVID-19 on an airplane. We expect that air travel is not likely to get back to normal until we're closer to a widely administered vaccine - so we're in this for the long haul. And I am going to keep encouraging our team to explore and implement new ideas, new technologies, new policies and new procedures that better protect our customers and employees."

airflow configuration onboard

On commercial aircraft, fresh air flows downward into the cabin from ceiling vents and exits the cabin at the floor and sidewalls. That air is then routed through the HEPA filters and mixed with fresh, outside air before returning back to the cabin. According to Boeing, that top-to bottom pattern, and frequent air exchange helps minimize front-to-back air movement and reduces the potential for spread of contaminants from people, such as through sneezing or coughing.

The system replaces the entire volume of cabin air every 2-3 minutes by providing 50% HEPA filtered, recirculated air mixed with 50% outside air, which allows a constant flow of either fresh or HEPA filtered air throughout the cabin. In addition, United has been partnering with the Defense Advanced Research Projects Agency (DARPA) to study how effectively the unique airflow configuration onboard an aircraft can prevent the spread of aerosolized particles among passengers and crew.

air filtration procedure

During a review of its cleaning and safety procedures with its United CleanPlus partners - Clorox and the Cleveland Clinic - United identified new opportunities during boarding and deplaning to help prevent the spread of the coronavirus. Already, the airline boards passengers back-to-front and deplanes five rows at a time. The new air filtration procedure on mainline aircraft will maximize air flow volume and recirculation of cabin air for passengers from the moment they step onboard.

"HEPA filters are an effective way to ensure clean air on an aircraft," said Dr. James Merlino from The Cleveland Clinic.

Among the First to Require Masks

Customers who do not comply with United's policy risk having their travel benefits suspended

"United's new strategy of running the air filtration and circulation systems at maximum volume well before passengers board and until they deplane, adds one more layer of protection. In addition to air filtration, we have worked with the airline to enact measures such as mandatory masking, health screenings, disinfection, and touchless systems, as we believe layering on precautions, more than any one strategy alone, helps create the safest environment possible."

United was one of the first airlines in the country to mandate that everyone onboard wear a face covering, providing complimentary masks to any customer or employee who needs one. When worn properly, face coverings prevent particles from one passenger's respiratory system from getting into the air and then potentially infecting others. Customers who do not comply with United's policy risk having their travel benefits suspended.

Limiting Number of Passengers on Board

The airline is also taking steps to limit the overall number of people on board and separate customers wherever possible. United switched to a larger plane 66 times a day in May and June, for a total of more than 4,000 flights during those months, creating more space onboard.

As a result, the airline's consolidated average seat factor - or the percentage of occupied seats including customers and non-revenue passengers - was 38% in May; 57% in June and is expected to be about 45% in July, with less than 15% of flights operating with more than 70% seats filled.

advanced automated seating tool

United is focused on delivering a new level of cleanliness on the ground and in the air

When United flights are less full, the airline's advanced automated seating tool assigns seats in a way that maximizes the space on board - and the distance between customers. And since May, United has been contacting customers via email and through the United app - as much as 24 hours in advance - if their flight is expected to be more than 70% full and gives them options to switch to different, less full flights for no additional fees.

Customers also have the option to cancel their flight and receive a credit for future travel. To date, the overwhelming majority of customers choose to keep their travel plans the same. United is focused on delivering a new level of cleanliness on the ground and in the air.

ensure clean environment

In addition to the vital initiatives mentioned above, several of the airline's precautionary measures to further ensure a cleaner environment include:

  • At Check-In

Implementing temperature checks for employees and flight attendants working at hubs and other airports throughout the airline's system

Installing sneeze guards at check-in and gate podiums

Promoting social distancing with floor decals to help customers stand six feet apart

Becoming the first airline in the world to roll out touchless check-in capabilities for customers with bags

  • At the Gate

Disinfecting high-touch areas such as door handles, handrails, elevator buttons, telephones and computers

Providing hand sanitizer and disinfectant wipes

Rolling out Clorox Total 360 Electrostatic Sprayers in select markets to disinfect gate areas at United's hub airports

Enabling customers to self-scan boarding passes

Boarding fewer customers at a time and, after pre-boarding, boarding from the back of the plane to the front

Introduced real-time seat assignment update text and email notifications to further United's touchless airport experience

  • On Board

Using electrostatic spraying to disinfect most aircraft prior to flight

Disinfecting high-touch areas - such as tray tables and armrests - prior to boarding

Reducing contact between flight attendants and customers during snack and beverage service

Deplaning in groups of five rows at a time to reduce crowding

Providing onboard items including pillows and blankets upon request

Download PDF version Download PDF version

In case you missed it

2025 AHR Expo: Top Innovations In HVACR Announced
2025 AHR Expo: Top Innovations In HVACR Announced

The AHR Expo (International  Air-Conditioning, Heating, Refrigerating Exposition) today announced the winners of the 2025 AHR Expo Innovation Awards. Winners are chosen annua...

Johnson Controls Center Develops And Tests HVAC Systems For Data Centers
Johnson Controls Center Develops And Tests HVAC Systems For Data Centers

Johnson Controls’ Advanced Development Engineering Center (JADEC) in New Freedom, PA., about 25 miles from Philadelphia, highlights and demonstrates the company’s capab...

Airzone Aidoo Pro Enhances VRF Energy Efficiency
Airzone Aidoo Pro Enhances VRF Energy Efficiency

The Olsen Group, based in Boca Raton, Florida, is a national pioneer in HVAC energy optimization. Donald Olsen and his seasoned team of HVAC control specialists have been in busine...

vfd