NTSB to FAA: Require Carbon Monoxide Detectors in General Aviation Aircraft


Two photos of cracked engine exhaust mufflers.

​Left: Cracked engine exhaust muffler through which carbon monoxide escaped and entered the cabin of a Mooney M20C airplane resulting in the Feb. 2, 2017, crash in Ellendale, Minnesota (CEN17LA101). FAA photo. Right: Cracked engine exhaust muffler through which carbon monoxide escaped and entered the cabin of an Aeronca 7AC airplane resulting in the March 20, 2016, crash in Ellsworth, Nebraska (CEN16FA130). NTSB photo.​

​​WASHINGTON (Jan. 20, 2022) — The National Transportation Safety Board has called on the Federal Aviation Administration for the second time to require carbon monoxide detectors in general aviation aircraft, the agency said in a safety recommendation report released Thursday.

The NTSB identified 31 accidents between 1982 and 2020 attributed to carbon monoxide (CO) poisoning. Twenty-three of those accidents were fatal, killing 42 people and seriously injuring four more. A CO detector was found in only one of the airplanes and it was not designed to provide an active audible or visual alert to the pilot, features the NTSB also recommended.

“Carbon monoxide is dangerous for pilots and passengers alike—which is why the NTSB recommended that general aviation aircraft be equipped with carbon monoxide detectors in 2004,” said Chair Jennifer Homendy. “Once again, we’re asking the FAA to act before lives are lost to carbon monoxide poisoning.”

An odorless gas byproduct of engine combustion, CO can enter the cabin of general aviation aircraft through defective or corroded exhaust systems or damaged or defective firewalls, door seals, landing gear compartments or steering boots.

​The NTSB, citing numerous accidents caused by CO poisoning, first recommended the FAA require CO detectors in general aviation aircraft with enclosed cabins and forward-mounted engines in 2004.

The FAA declined to require detectors and instead recommended that general aviation airplane owners and operators install them on a voluntary basis. The FAA also recommended exhaust system inspections and muffler replacements at intervals they believed would address equipment failures before they led to CO poisoning.

The NTSB said in the report that the list of CO related accidents showed that the FAA’s actions were “inadequate to protect pilots against the hazards of CO poisoning.” The NTSB also said that since toxicology testing for CO was only performed as part of fatal accidents when a suitable blood specimen could be obtained, the actual number of accidents caused be CO poisoning may be higher.

The NTSB also recommended that the Aircraft Owners and Pilots Association and the Experimental Aircraft Association inform their members about the dangers of CO poisoning, encourage them to install CO detectors and ensure their aircraft exhaust systems are thoroughly inspected during regular maintenance.

The safety recommendation report is just the latest effort by the NTSB to alert the general aviation community to the dangers of CO poisoning. Links to the safety alerts, videos and blogs the NTSB issued about this flight safety hazard are provided below:

The complete 11-page safety recommendation report is available at https://go.usa.gov/xtkpw​.

To report an incident/accident or if you are a public safety agency, please call 1-844-373-9922 or 202-314-6290 to speak to a Watch Officer at the NTSB Response Operations Center (ROC) in Washington, DC (24/7).