Definition
The chamber inside a pyrotechnic or cartridge-type starter that holds the cartridge and contains the high-pressure gases produced when the cartridge is fired. These gases are then directed to drive the starter turbine that rotates the engine for starting.
Plain English
The sealed compartment in a cartridge starter where the starter cartridge is loaded and burned. The hot gases from the burning cartridge are captured here and routed out to spin the engine.
Context Anchor
Seen in piston-engine maintenance and engine construction discussions, especially when describing cylinders, cylinder heads, and combustion chambers.
Derivation
Breech comes from Old English brec, referring to the rear or back end of something. In firearms, the breech is the back end of the barrel where the cartridge is loaded. The aviation use carries the same idea: the closed-off rear section where a cartridge is held and fired.
Why Pilots Care
The breech chamber must maintain proper compression and sealing for safe engine power and to avoid detonation or power loss.
Intuition Check
Do not read breech as breach. Here, breech means the closed end of a cylinder, not a break, gap, or violation.
Example Sentence 1
Before starting the engine, the ground crew loaded a fresh cartridge into the breech chamber of the starter.
Example Sentence 2
Carbon buildup in the breech chamber can reduce engine performance during a cylinder inspection.