Three defects can show up on exhaust systems; read on to find out exactly what they are and how to find them.

February 2015-

Light airplane exhaust systems don’t garner as much attention as a carburetor or induction air filter, yet these systems must be maintained as attentively as any other engine accessory, if not more so. That prosaic exhaust system is the only fire control system under your cowling.
Exhaust systems rarely rate a second thought. Why? Because unless your airplane is turbocharged or turbo-normalized, the exhaust system doesn’t have any moving parts—it just sits there.
Light aircraft exhaust systems are designed to collect hot exhaust gases from each cylinder and route these gases safely out of the engine compartment. Systems in single-engine airplanes also flow the gases through rudimentary metal heat exchangers that radiate heat to outside air that’s used to provide cabin and carburetor heat.
It’s common to mistakenly believe that these heat exchangers are mufflers because they look like an automobile muffler. Some heat exchangers include internal baffles designed to slow the exhaust gases in order to increase the amount of heat transfer. Twin-engine Pipers don’t have these heat exchangers; they utilize Avgas fuel combustion heaters for cabin heat. (For an in-depth look at combustion heaters, refer to the November 2014 issue of Piper Flyer. —Ed.)