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Cabin of PR-WJK, sporting Webjet’s updated interior. (Photo: João Paulo Carisio)

Honeywell Unveils New Cabin Air Catalyst

Earlier this week, Phoenix, Ariz.-based Honeywell Aerospace unveiled a new catalyst for aircraft cabin systems, which will aim to reduce delays and maintenance issues caused by cabin odor events.

The new catalyst from Honeywell comes at a time when cabin odor events have seen an increase over the past several years. In 2018, the Federal Aviation Administration issued a safety alert directing carriers to ensure their procedures and checklists “specifically address recognition, differentiation and mitigation of odors, smoke and/or fumes in the cabin and/or flight deck.”

Depending on the severity of a cabin odor event, it can cause a flight to be delayed, or, even worse, require passengers to obtain medical attention. For example, in 2019, a Spirit Airlines flight departing Las Vegas experienced an oil smell during taxi. The incident resulted in the evacuation of the aircraft, several passengers being sent to the hospital and required the aircraft to undergo inspection and maintenance.

The basic principles of how air gets to the cabin of an aircraft show how these types of cabin odor events can occur. The air required for air conditioning and pressurizing the cabin of an aircraft comes from the engines and is known as “bleed air.” Although bleed air passes through systems that cool the air and remove contaminants from it, bleed air can still occasionally contain volatile organic compounds (VOCs) and fumes causing odors in the cabin.

The new fourth-generation catalyst from Honeywell is known as Combined Hydrocarbon Ozone Catalyst (CHOC4). CHOC4 gets applied to the aircraft’s ozone converter to absorb compounds which cause undesirable odors in the cabin.

Tom Hart, Vice President and General Manager of Air & Thermal Systems at Honeywell gave a statement regarding CHOC4, saying, “severe smell-in-cabin incidents can cost airlines up to $50 million per year in flight disruptions and unscheduled maintenance,” “CHOC4 reduces VOCs from the engines and bleed air supply, thereby reducing the severity and frequency of these incidents.”

According to Honeywell, CHOC4 can be applied to an existing ozone converter unit as part of normal maintenance. It is now available for the Airbus A320 and Honeywell has plans to expand its availability to more platforms early next year.


  • Jordan joined the AG team in 2018 after attending AAviationDay in Philadelphia. He is actively pursuing his private pilot certificate and has been an aviation enthusiast since childhood. An attorney by trade, Jordan jokingly refers to himself as a “recovering litigator” and now focuses on subcontracts management. Jordan focuses his writing on innovations in commercial aviation, aviation history, and other interesting topics he feels are worthy of discussion in the community.

Jordan Green

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