The FAA has released a Special Airworthiness Information Bulletin (SAIB) advising the owners of general aviation aircraft of the need to properly inspect and maintain their exhaust systems to prevent carbon monoxide leakage into the cabin, as well as install a carbon monoxide detector in the cabin.
The SAIB is in response to an NTSB investigation of a Dec. 17, 2000, accident, where a Beech Model BE-23 aircraft hit terrain, killing the commercial-rated pilot, the sole occupant of the airplane. The NTSB determined the probable cause of the accident was, in part, “the pilot’s incapacitation due to carbon monoxide (CO) and a fractured muffler.”
The FAA tasked Wichita State University to conduct research that focuses on carbon monoxide safety issues as they apply to general aviation products. A technical report titled “Detection and prevention of carbon monoxide exposure in General Aviation Aircraft, Document No. DOT/FAA/AR-09/49, dated October 2009” was published. Available here, the report shows that 43 commercially available CO detectors, sampled from each of the five sensor technology types (biometric, electrochemical, spot, infrared, and semiconductor), were surveyed to determine the most appropriate sensor technology. The electrochemical sensor-based CO detectors were found to be most suitable for use in the GA environment. Limited field testing using portable electrochemical CO detectors was conducted in two GA aircraft models to determine the best location for a CO detector. Based on the analyses of collected CO data, the instrument panel appeared to be the best location for the placement of CO detectors, FAA officials note. The report adds that, to increase the probability of being able to detect at least 50 parts per million (PPM) anywhere in the cabin, the CO detector should be set at a lower alarm threshold of 35 PPM.
The FAA recommends that aircraft owners:
- Consider the information in the technical report, and use a CO detector while operating your aircraft.
- To detect leakage of gases into the cabin due to cracks in the exhaust system, conduct engine run up tests with cabin heat on and check for CO in the cabin with a hand-held CO detector during 100 hour and annual inspections.
- Continue to inspect the complete engine exhaust system during 100 hour/annual inspections and at inspection intervals recommended by the aircraft and engine manufacturers in accordance with their applicable maintenance manual instructions.
For more information: FAA.gov