Definition
The combustion of unburned fuel in the exhaust system of a turbine or reciprocating engine, producing visible flame extending from the exhaust outlet. It typically occurs during engine start, shutdown, or transient power changes when excess fuel reaches the exhaust before fully burning in the combustion chamber.
Plain English
Flames coming out of the engine exhaust because some fuel didn't finish burning inside the engine and instead burned in the tailpipe.
Context Anchor
You may see this term in discussions of engine starting, shutdown, or abnormal engine operation.
Derivation
From 'torch,' meaning a flaming light. The term describes the literal appearance: a torch-like flame shooting from the exhaust.
Why Pilots Care
Signals incomplete combustion that can lead to engine damage, carbon buildup, or fire risk if left uncorrected.
Grounding Statement
Picture a brief flame coming from the exhaust pipe because fuel is burning there instead of inside the engine.
Intuition Check
Torching does not mean the entire aircraft is on fire. In this aviation use, it means fuel is burning in the exhaust area and making a visible flame.
Example Sentence 1
The ground crew reported torching from the right engine during start, so the pilot aborted and motored the engine to clear excess fuel.
Example Sentence 2
Mild torching at idle often clears once the engine reaches operating temperature.