Definition
An exhaust duct on a turbine engine that is split into two separate passages, allowing the exhaust gas stream to flow around an obstruction such as a tail rotor drive shaft, structural member, or aircraft component before recombining or exiting through two outlets.
Plain English
An exhaust pipe that is divided into two channels so the hot gas can flow around something in its path instead of being blocked by it.
Context Anchor
Seen in aircraft engine and maintenance discussions, especially where exhaust piping or turbine-engine exhaust outlets are described.
Derivation
From the Latin 'bi-' meaning 'two' and 'furca' meaning 'fork.' Bifurcated literally means 'forked into two branches' — which is exactly what this duct does to the exhaust path.
Why Pilots Care
Correct operation of the bifurcated duct maintains proper thrust balance and can affect engine noise levels and fuel efficiency.
Intuition Check
Do not read bifurcated as simply meaning “two separate exhaust systems.” It means one exhaust passage that splits into two branches.
Example Sentence 1
The helicopter's turbine exhaust passes through a bifurcated duct that routes the gas around the tail rotor drive shaft.
Example Sentence 2
The mechanic replaced the seals on the bifurcated exhaust duct to restore proper separation of the core and bypass flows.