Safety Alerts SA-070 and SA-069 warn mechanics and pilots that the risk of carbon monoxide poisoning is generally overlooked and underestimated – a dangerous prospect given that many internal combustion engine airplanes are heated by air warmed by exhaust systems using a heater shroud. A defect or leak in the exhaust pipes or muffler can introduce the colorless, odorless and tasteless gas into the cockpit – with sometimes fatal results.