MEC&F Expert Engineers : Some Passengers Who Became Ill on Diverted Delta Flight Had Elevated Carbon Monoxide Levels in Their Bodies

Sunday, July 10, 2016

Some Passengers Who Became Ill on Diverted Delta Flight Had Elevated Carbon Monoxide Levels in Their Bodies







DEAN SCHABNER
Sunday, July 10, 2016 12:58PM Some of the passengers who became ill on a Delta flight from Atlanta to Denver Saturday afternoon -- prompting its diversion to Tulsa, Oklahoma -- had elevated levels of carbon monoxide in their bodies, a Tulsa Fire Department official said Saturday evening.

The cause of the increased carbon monoxide levels was not yet determined. An investigation continues.

Once passengers went outside and got fresh air, their levels returned to normal, said fire department spokesman Stan May

"The flight crew of Delta flight 1817 from Atlanta to Denver elected to divert to Tulsa when a few customers reported feeling ill," the Atlanta-based airline said in a statement Saturday afternoon. "The safety and security of our customers is our top priority."

Initially, officials at Emergency Medical Services Authority in Tulsa said 100 people had been assessed, and nine reported having the same symptoms -- but the cause was unknown.

Then later in the day, May released the information about the elevated carbon monoxide levels, adding that the number of people complaining of symptoms had risen 12. One person was taken to a hospital, but he said it was not related to the carbon monoxide.

Officials were re-screening passengers at about 8:30 p.m. local time to get them on another Denver-bound plane. 


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Overlooked Safety Issue
 
Carbon monoxide poisoning is a safety issue that pilots tend to ignore, even though it is the most common industrial poisoning accident in the United States. When carbon monoxide poisoning occurs, it can have significant and fatal consequences for aircraft occupants.


Carbon monoxide is a by-product of the incomplete combustion of carbon-containing materials. 


Aviation fuel contains carbon and is a ready source of carbon monoxide when burned. Expect carbon monoxide whenever an internal combustion engine is operating, and even though piston engines produce the highest concentrations of carbon monoxide, exhaust from turbine engines could also cause carbon monoxide poisoning. In addition, expect carbon monoxide whenever a fire occurs, as commonly happens in a post-crash environment.


Carbon monoxide is truly a hidden menace because by itself, it is both a colorless and odorless gas. An individual would not be aware of its presence until symptoms developed, or during treatment it was determined exposure had occurred. The least desirable situation would be incapacitation. In
this case, the victimis powerless to do anything about the exposure. 


Fortunately, because it is a by-product of combustion, carbon monoxide is frequently associated with other gases that do have an odor and color.
By avoiding an environment with known combustion fumes, you will also avoid carbon monoxide. The true problem comes when exposure is so gradual that you don’t perceive it. You can become incapacitated before you can vacate the environment. In an airplane, the result most likely will be a fatal accident.

 


 Why Carbon Monoxide Poisoning Should Concern Pilots and Passengers
What is not known is the full extent of carbon monoxide poisoning in aviation. Analysis of toxicology samples from fatal U.S. aircraft accidents between 1967 and 1993 showed that at least 360 victims had been exposed to sufficient carbon monoxide before or after the crash to impair their abilities. Non-fatal carbon monoxide poisoning in aviation is likely a more common occurrence than currently believed.


No one is sure how many times pilots or passengers became ill, not realizing they had been exposed to carbon monoxide. Because no significant incident or incapacitation occurred, the matter was not reported and, hence, not investigated. Symptoms that could be attributed to airsickness, altitude hypoxia, fatigue, or a variety of other conditions actually could have been carbon monoxide poisoning.


Exposure and symptoms may occur repeatedly over several flights until, finally, someone suspects carbon monoxide or, tragically, an accident claims a victim. No database presently exists that accurately collects or tracks non-fatal aviation carbon monoxide exposure information.

Toxicity Mechanism
Carbon monoxide has a very high affinity for hemoglobin, the molecule in blood responsible for transporting oxygen through the body. Carbon monoxide has affinity of 240 times that of oxygen. 


Carbon monoxide tightly attaches to the hemoglobin, creating the compound carboxyhemoglobin, which prevents oxygen from binding, thereby blocking its transport. The result is hypoxia but through a mechanism different from that
produced by altitude. However, with respectto symptoms, the end-effects can be very similar.


There should be little or no carbon monoxide in the blood of individuals who have not been exposed to smoke or other by-products of combustion. People
living in polluted urban environments may have between 3-10% carboxyhemoglobin concentrations because of the carbon monoxide contained in the smoke and fumes they inhale, while a cigar smoker could have up to 15%. 


People in certain occupations such as foundry workers, welders, mechanics,
firefighters, and tollbooth or tunnel attendants that expose them to products of combustion may also have elevated carbon monoxide baseline levels.


Symptoms
The most common symptoms of carbon monoxide exposure are shown in Table 1. These symptoms are typical for an individual with normal hemoglobin at sea level. You can expect these symptoms to worsen at altitude and/or appear sooner than they otherwise would. Wide personal variations may also occur, depending on the circumstances andwhether or not the indificual smokes.

Protection From Carbon Monoxide Exposure
First and foremost is pilot education and awareness. Pilots must understand the danger posed by carbon monoxide poisoning and should be alert to the symptoms.


Any unusual cabin smell or sensation of illness should call for immediate troubleshooting.


• Turn the cabin heat fully off.
• Increase the rate of cabin fresh air ventilation to the maximum.
• Open windows if the flight profile and aircraft’s operating manual permit such an action.
• If available (provided it does not represent a safety or fire hazard), consider using supplemental oxygen.
• Land as promptly as possible.
• Do not hesitate to let Air Traffic Control know of your concerns, and ask for vectors to the nearest airport.
• Once on the ground, seek medical attention.
• Before continuing the flight, have the aircraft inspected by a certified mechanic.

Safeguards
• The best protection against carbon monoxide poisoning is to avoid exposure.
• Aircraft operators and pilots must ensure that heating/ventilation systems and exhaust manifolds in their aircraft are all in good working order, as specified by the manufacturer and the Federal Aviation Administration.
• Certified mechanics must conduct all required inspections.
• Special attention should be paid to older aircraft because of corrosion or simple wear and tear.
• A certified mechanic should verify firewall and aircraft structural integrity and seal any  defects.

•Finally, several devices are available to monitor for carbon monoxide. The least expensive are handheld or stick-on colorimetric devices that change color in the presence of carbon monoxide. Whileeffective, they are not perfect or foolproof. Powered detectors for aviation use are available as either portable or panel-mountedunits and provide greater reliability.