Cabin Air Quality (CAQ)

Cabin Air Quality
Cabin air quality refers to the air supplied to the cockpit and cabin of an aircraft, often sourced from the engines using a “bleed air” system. This air can become contaminated with fumes from engine lubricants, hydraulic fluids, or de-icing chemicals, particularly if seals fail or under certain operating conditions. Contaminated air may lead to health and safety concerns for crew and passengers, including short- and long-term effects such as headaches, fatigue, nausea, and neurological symptoms. This is called Aerotoxic Syndrome.
Aerotoxic Syndrome
Aerotoxic syndrome is a condition linked to exposure to contaminated cabin air, typically involving organophosphate compounds from engine oils. Symptoms range from neurological effects (e.g., numbness, confusion) to chronic health issues. Key findings include:
- Cause: Exposure to pyrolysed engine oils containing toxic compounds such as tricresyl phosphate (TCP).
- Vulnerable Groups: Around 30% of individuals are poor detoxifiers and may be more susceptible.
- Challenges: Establishing causality is difficult due to industry resistance, lack of funding for independent research, and inadequate large-scale studies.
Actions Taken on Cabin Air Quality
BeCA’s Efforts:
- Advocacy: The Belgian Cockpit Association (BeCA) has been actively involved in addressing CAQ issues, demanding stricter regulations and better research. BeCA participated in initiatives like the European Committee for Standardization (CEN/TC 264) working group to establish new norms on Cabin Air Quality.
- Awareness and Reporting: BeCA emphasizes the importance of reporting fume events, as under-reporting hinders progress. Reporting is mandatory under EU law (EU376/2014). Additionally, crews can opt to report via GCARS.
- Participation in Research and Conferences: BeCA presented during several Global Conferences on Cabin Air Quality and collaborates with other pilot associations to push for safety standards and technological advancements.
- Developing practical guidance: In close cooperation with the Global Cabin Air Quality Executive (GCAQE), BeCA developed a Post-Smoke/Fume Event Procedure which serves as practical guidance for crews based on the peer-reviewed Medical Protocol published by Burdon et al. (2023).
Current Technological and Procedural Changes:
- Efforts to retrofit aircraft with air filtration systems have been initiated by some airlines, such as DHL and EasyJet.
- Development of detection instruments for cabin air contamination is ongoing.
- In 2021, NYCO, a French engine oil and lubricant manufacturer, issued a patent for a new engine oil anti wear additive said to address the issue of ‘Aerotoxic Syndrome’. In 2024, the 940 SE oil received military specification MIL-PRF-23699 approval.
What to do in case of a Fume Event?
To report a fume event:
- Follow the checklist from the Post-Smoke/Fume Event Procedure.
- Record symptoms for crew and passengers.
- Seek medical assistance (use the checklist mentioned above)
- Fill out specialized smoke and smell reports.Inform the airline and make a technical log entry.
- Complete an occurrence report per EU376/2014, detailing the event and its effects.
- Follow-up
If you have specific questions about any aspect of cabin air quality or Aerotoxic syndrome, feel free to ask!