We recently discovered that the onboard carbon monoxide detector (CO) could go into an alarm mode prematurely. Guardian Avionics, the manufacturer of the CO Detector, has recently issued Service Bulletin 23-454-01, indicating CO Detectors with software versions other than 1.62 can go into an alarm mode if the carbon monoxide level rises above 20 PPM, instead of the required threshold of 50 PPM. This may result in an early warning to the MFD causing the pilot to be prematurely concerned about carbon monoxide build up in the cabin.We released Service Bulletin SB2X-31-06 which inspects for the software revision and replaces the CO detector if necessary.
