Some onboard odors are unpleasant (smelly food, lavatories, poor hygiene, etc.) but most of them are not toxic.  The term “fumes”, refers to odorous and unpleasant smells coming from the air supply vents, not from something in the cabin. The type of fumes that are most concerning are oil and hydraulic fluid as breathing these fumes can cause both flight safety and health issues. It’s important to distinguish between fumes and other cabin odors.  A “fume event” is what happens when fumes contaminate the ventilation air that enters into the cabin through the air vents.

For more information on potential air supply sourced fumes, please refer to Air Quality Guidance.

Approximately 50% of the cabin air is dumped overboard and replaced with fresh outside air that is mixed with the re-circulated air remaining onboard.  It is the bleed air process where in lies the potential for contamination.

Back in the 1950s, aircraft designers came up with the design for bleed air.  Bleed air is the process of extracting (or “bleeding”) hot compressed air off the engines during flight, cooling it, mixing it with some of the re-circulated cabin air, and routing it back to the cabin and flight deck for ventilation.  The auxiliary power unit (APU) uses a similar design, compressing the outside air during ground operations.  This design saves on fuel thus reducing costs and is used almost universally within the airline industry.  To date, the only aircraft that does not ventilate the cabin using bleed air from the engines is the Boeing 787.

Over time, concerns have been raised about the potential for oil and hydraulic fumes to contaminate the ventilation air.  The bleed air design is susceptible to toxic cabin air fume events.

Despite the fact that the air is compressed in the engines and it is possible for the engines to leak oil, there is no filter between the engines and the cabin.

One filtration company developed a bleed air filter for the flight deck only for one aircraft type back in 2010. More recently, the same company has developed a bleed air filter for the whole aircraft that is suitable for certain aircraft types. That filter is being tested on aircraft in 2018 on one European carrier and at least one U.S. carrier.

Some crews think that a transient dirty sock or oily smell in the cabin is normal at certain times, like when the auxiliary power unit (APU) is turned on or the aircraft starts to descend.  Those types of fumes should not be considered normal, but they’re often not reported and little attention is paid to them. Flight Attendants work in an enclosed space operating at 35,000 feet – oil in the air supply should not be normal and ventilation air should be clean.

Research has shown that the majority of reported fume events involving oil or hydraulic fluid only involve a bad smell and no smoke or haze.  The majority of those reported events still cause crew members to get sick and have operational impacts like diverted or canceled flights.  If there is an unpleasant smell coming from the vents, it is critical to take immediate action.

Report it! If you are sick, it matters and you need to document it and see a physician. Research shows that people can react differently to the same fumes, depending on their genetics, exposure history, medications, and other factors. It is natural to second-guess yourself if you are the only one exhibiting symptoms, but put your health first.

No.

If the air supply is contaminated with fumes, maintenance needs to take action to ensure that the aircraft is safe to operate and people onboard don’t get sick. Reporting is much better than regret. There are many examples of crews who smelled fumes on the ground and said nothing because they didn’t want to be the one to speak up, wanted to get home, or were uninformed. Dealing with the consequences of a fume event, which takes much more time and money, and is much harder for the airline and the people who get sick.

It is critical that if you smell something unusual coming from the vents, to say something and report the situation immediately.

Not necessarily. The location of fumes in the cabin and flight deck depend on the aircraft type and the origin of the fumes (left engine, right engine, or auxiliary power unit [APU]). Pilots are trained to understand this, so be sure to report where in the cabin you notice the fumes the most. For example, on a Boeing 737, oil sourced to the left engine will be most noticeable in the flight deck and forward cabin, whereas oil sourced to the right engine will be most noticeable in the mid and aft cabin, but not in the flight deck. If the APU is the issue, fumes will likely be noticeable throughout the cabin and flight deck and can even manifest inflight after the APU has been shut down. On Airbus aircraft, that distinction between right and left engine fume source won’t be as clear, but part of the logic still holds.

A fume event can happen anytime but the most likely times are when the auxiliary power unit (APU) or main engines are under stress due to a power setting change. The main examples are APU start, engine start, take-off/climb, and top of descent. It is important to be aware of the type of odor, whether or not the fumes are coming from the vents, where in the cabin the fumes are most noticeable, and when the fumes started. All of those reporting details provide the pilots with important clues as to the source of the fume event and how to manage the situation.

No. Based on review of airline maintenance records, about 30% of documented fume events – where every detail is consistent with oil or hydraulic fumes – are “no fault found.”  One recognized and likely underreported cause of fumes is over-servicing an oil or hydraulic reservoir which can cause spillage that can contaminate the supply air. Spillage isn’t a mechanical failure as nothing is broken.  Eventually the excess oil in the system burns up and the problem improves over time, even without maintenance intervention. Despite this, a fume event can still occur and crew members can exhibit symptoms of exposure.

Yes, but not always. Oil fumes, hydraulic fluid fumes, fuel fumes, and exhaust fumes can all contain carbon monoxide gas if they get heated to high enough temperatures in the engine/auxilary power unit (APU).  The operating temperatures in those systems range from 250 to 950°F, depending on the phase of flight and air supply source. Carbon monoxide gets formed starting at temperatures around 450°F.  The cabin air supply is not filtered for carbon monoxide prior to being introduced to the cabin.

Immediate symptoms of carbon monoxide exposure include:

• Headache
• Dizziness
• Fatigue
• Disorientation/mental confusion
• Giddiness
• Fainting

Symptoms of exposure to Volatile Organic Compounds (VOCs), found in engine oil and hydraulic fluid, are very similar to carbon monoxide exposure.

Often, the symptoms that crews report inflight suggest exposure to carbon monoxide gas or some other chemical that displaces oxygen in the blood. Examples include dizziness, headache, unusual fatigue, slowed thinking, impaired vision, and “brain fog.” Oxygen should help with those types of symptoms.

It’s not a good idea to avoid seeing a physician if experiencing symptoms.  In documented fume events, crews often report having experienced symptoms like headache, dizziness, stomach cramping, and slowed thinking.  In some cases, crews later develop new and persistent symptoms after exposure to fumes.  Right after an event, it is impossible to know if longer-term symptoms will develop.  It is important to get examined and evaluated by a physician to get medical advice about the symptoms being experienced and to establish documentation in case more symptoms develop later.

Utilizing the Flight Attendant Onboard Air Quality Checklist and working with your crew:

• Quickly try to identify the source (in cabin item or coming from vents)
  • If in-cabin item, attempt to address directly
  • If coming from cabin air vents, notify the Flight Deck of the following by clearly stating from the completed AQ Checklist:
    • Description and strength of fumes/odor
    • Apparent source of fumes/odor (if air supply, any obvious source outside cabin? (De-icing, exhaust, etc.)
    • Location in cabin of fumes/odors
    • Phase of flight when fumes/odors first detected
    • Physiological effects, if any, experienced by crew or passengers
• If adverse physical reaction consistent with hypoxia (headache, lightheaded, dizzy, fainting, euphoria, poor coordination, impaired vision, impaired judgment), don oxygen per company First Aid policy.
• If you or a flying partner require additional, immediate medical attention:
  • In the air, notify the Flight Deck to call MedLink
  • At the gate: ask CSA to call paramedics. Deplane if possible and call Global Crew Support at (800) 350-4390
• If you go to the hospital/urgent care, take your Air Quality Quick Reference Card*.  Show your physician the “Info for your Doctor” section.  If you don’t have a card you can access a printable version by clicking here.

AFA has developed comprehensive resources to provide information on what to do in the event of a suspected fume event.  This information can be accessed by clicking here.

*It is recommended that you keep this card with you at all times with your company ID or in your purse/wallet so that it is accessible when needed.  Cards can be obtained from your Local Air Safety, Health, & Security Committee or a printable version can be accessed by clicking here.

• If notification is provided by the pilots, an inflight supervisor should either meet the flight (if arriving at an airport where an inflight base is located) or will call you and ensure you are all off the aircraft and away from any further potential for exposure. If you have not been contacted by management, make sure you get the support you and your crew need by calling AFA’s Air Safety, Health and Security Committee (ASHSC) Vice Chairperson at (206) 457-2010, extension 1101 and an on duty Inflight Supervisor.    There are times when management and AFA are not aware an event has occurred, usually because the incident has not been reported. It is imperative that you notify the flight deck as soon as you become aware of a fume event. Filing a Flight Attendant Incident Report (FAIR) through ReportIt! is required documentation and extremely important but does not send an immediate alert to management nor trigger an immediate response.  The report you send through ReportIt! is generally reviewed the following business day.
• If you need immediate medical assistance the paramedics (if not already there) will be notified.
• You will be given the number for Global Lifeline (800-350-4390), who will speak with each Flight Attendant who has been exposed and advise on need for further medical treatment and the location of the nearest facility. Global Lifeline will approve payment for treatment that will then be billed to workers’ compensation once a claim is processed.
• If seeking medical treatment, you should be accompanied to the facility by a supervisor or another unexposed Alaska Airlines employee unless you decline.
• A member of inflight management will complete an Air Quality Checklist with each of you to document and communicate the event to the necessary departments involved for investigating the cause and tracking the event.
• Your Air Safety, Health & Security Committee (ASHSC) Vice Chairperson or another AFA ASHSC representative will be reaching out to your crew via text and email with important air quality information. Please read and call your ASHSC Vice Chairperson back for further guidance as needed.
• A representative from the AFA Employee Assistance Program (EAP) will be reaching out to you via email to provide support.
• Be sure to maintain communication with Crew Scheduling and the Inflight Duty Manager/Supervisor.
• If you need a hotel, Crew Scheduling or the Inflight Duty Manager/Supervisor will arrange it for you.

Any questions and/or concerns can be directed to the AFA ASHSC Vice Chairperson at (206) 457-2010, extension 1101.