Summary
We propose to adopt a new airworthiness directive (AD) for certain Cirrus Design Corporation (CDC) Model SR20 airplanes. This proposed AD would require an inspection and replacement as necessary of the heat exchanger. This proposed AD results from the discovery of engine exhaust fumes in the cabin of CDC Model SR20 airplanes. We are proposing this AD to detect and correct leaks in the exhaust system, which could result in exhaust gases leaking into the cabin heating system. This condition could lead to carbon monoxide in the cabin and incapacitation of the pilot.