CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
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EFG
BURNER STAGING VALVE
EFFECTIVITY
73-11-70 Page 1
ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03
CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
BURNER STAGING VALVE
The purpose of the Burner Staging Valve (BSV) is to close the fuel supply to the staged manifold.
In this condition, only ten fuel nozzles are supplied with fuel.
The BSV is installed on a support bracket on the core engine at the 6 o’clock position.
EFG
BURNER STAGING VALVE
CTC-201-103-01
EFFECTIVITY
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ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03
CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
BURNER STAGING VALVE
The BSV is used in decel to keep the fuel flow above the lean flame-out limit.
To safely work close to this limit, the ECU cuts 10 of the 20 engine fuel nozzles.
The effect is that the same amount of fuel is provided in the combustion chamber, but on 10 fuel nozzles only. In this condition, the lean flame-out is well above the flame-out limit and it is impossible to extinguish combustion.
The diagram indicates the switch limits between 20 and 10 fuel nozzles.
Two fuel supply manifolds, staged and unstaged, are installed on the fuel supply system.
Within the BSV support, the metered fuel is split into two flows, which are then delivered to the nozzles, through the two manifolds.
The unstaged manifold always supplies 10 fuel nozzles, and the staged manifold supplies the 10 remaining fuel nozzles, depending on the BSV position.
At the outlet of the BSV, each fuel supply manifold is connected to a “Y” shaped supply tube at approximately the 5 and 6 o’clock positions.
Each supply manifold is made up of two halves, which are mechanically coupled, and include 5 provisions to connect the fuel nozzles.
To improve the rigidity in between the manifold halves, connecting nuts are installed at the 6 and 12 o’ clock positions.
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CTC-201-104-02
EFFECTIVITY
73-11-70 Page 5
ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03
CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
BURNER STAGING VALVE
The BSV is a normally open, fuel shut-off valve that is controlled by the ECU, and fuel operated by the HMU.
The valve shuts off every other fuel nozzle in certain engine operations, to provide a better spray pattern and improve the engine flame-out margin.
The valve has dual redundant signal switches, which are open when the valve is open.
All open ports terminate in the mounting surface of the valve body and when the valve is installed on the mounting bracket, the ports are automatically connected. No external hydraulic or pneumatic lines are required.
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