Plane Carbon Monoxide Poisoning Risk Results in NTSB Warning for Pilots, Mechanics

Federal safety officials indicate that there needs to be more awareness of the risk of carbon monoxide poisoning among airplane pilots and mechanics, noting in a recent warning that the risk is often overlooked. 

The National Transportation Safety Board (NTSB) issued two safety alerts last month, SA-070 (PDF) and SA-069 (PDF) warning that carbon monoxide could build up in airplanes or hangars due to how airplane internal combustion engines are designed.

The alert indicates that many airplanes have a heater shroud, which uses air warmed by the exhaust system to heat the engine. If there is a leak or break in the exhaust pipe or muffler, lethal amounts of carbon monoxide could fill the cockpit in a short period of time.

The safety alerts note that cracks in the mufflers and tubes, and holes in the firewall can go unnoticed during inspections.

Door and window seals that have degraded or that leak can also let carbon monoxide into the cabin. This is of particular concern if the buildup occurs in flight, which could result in the pilot and crew being incapacitated, resulting in a crash.

This is not just conjecture on the part of the NTSB. A recent accident report found that this is precisely what caused an airplane crash in February in Ellendale, Minnesota. The pilot became disoriented, strayed off course and then crashed into an open field when he ran out of fuel. He was seriously injured, but survived the accident.

Investigators found several cracks in the muffler and the pilot’s blood showed signs of recent high levels of carbon monoxide poisoning shortly after the crash.

“The NTSB encourages aircraft mechanics to inspect exhaust systems, air ducting, firewalls, and door and window seals thoroughly at every 100-hour or annual inspection,” an NTSB press release states. “The agency encourages pilots to install a carbon monoxide detector on the instrument panel of their aircraft, noting that detectors with aural alerts and a flash notification are more likely to draw a pilot’s attention to the potentially lethal condition.”

Carbon monoxide is often described as the “silent killer”, as the gas has no smell, taste, color or other irritating factors that may allow individuals to detect a leak. Following prolonged exposure, symptoms of carbon monoxide exposure may result in mental confusion, vomiting, loss of consciousness and quickly cause death.

The CDC estimates that carbon monoxide poisoning kills more than 400 people in the U.S. per year, on average, making it the leading cause of fatal poisonings in the United States, due to the difficulty detecting the extremely toxic gas, which can quickly overcome an individual and result in permanent brain damage.

Individuals exposed to carbon monoxide typically experience symptoms similar to the flu. For individuals who survive exposure, many are left with devastating brain damage from carbon monoxide, which can impact them for the rest of their lives.