Definition
In small piston-engine aircraft, a heating system that supplies warm air to the cabin and to the windshield defrost outlets by routing outside air through a shroud surrounding the engine exhaust muffler, where the air is warmed by contact with the hot muffler surface before being ducted into the cockpit.
Plain English
A simple system that heats the cabin by passing fresh outside air around the hot exhaust muffler. The air picks up heat from the muffler and is then sent into the cockpit and to the windshield defroster vents.
Context Anchor
Seen in aircraft systems discussions, cold-weather flying, preflight checks, and use of the cabin heat control.
Derivation
Heating means making something warm. System comes from an older word meaning parts placed together. That helps here because the heating system is not just one knob; it includes the parts that collect, warm, control, and deliver cabin air.
Why Pilots Care
A functioning heating system prevents cold-related impairment of pilot performance and reduces windshield fogging from breath moisture.
Grounding Statement
When the pilot selects cabin heat, the aircraft sends air through the heating system so warm air can flow into the cockpit or cabin.
Intuition Check
Do not think of an aircraft heating system as the same as a home heater. In many small airplanes, cabin heat is closely tied to hot engine exhaust parts, so leaks or damage can become a safety problem.
Example Sentence 1
On a cold morning, the pilot pulled the cabin heat knob and warm air began flowing from the vents as the heating system drew air across the muffler shroud.
Example Sentence 2
During the preflight inspection the pilot verified that the heating system produced warm air without any exhaust odor.