DOC AIRBUS | AMM A320FPOWER PLANT DRAIN SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
A drain system is incorporated to collect fluids that are lost from the various APU components and to drain the exhaust system of any unwanted fluids such as rain water and cleaning fluids. For safety and operational reasons, all these fluids are collected and drained overboard via the APU compartment drain mast.
The APU compartment is designed to permit all excess fluids to gather at the lowest point from where they are discharged overboard via the drain mast.
All components of the drain system are fireproof.
** ON A/C NOT FOR ALL A drain system is incorporated to collect fluids that are lost from the various APU components and to drain the exhaust system of any unwanted fluids such as rain water and cleaning fluids. For safety and operational reasons, all these fluids are collected and drained overboard via the APU compartment drain mast.
The APU compartment is designed to permit all excess fluids to gather at the lowest point from where they are discharged overboard via the drain mast.
All components of the drain system are fireproof.
2. Component Location
** ON A/C NOT FOR ALL 
Drain System - Component Location| ------------------------------------------------------------------------------- |
| FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA |
| | | | | DOOR | REF. |
| ------------------------------------------------------------------------------- |
| DRAIN LINES 316 316AR 49-17-41 |
3. System Description
Drain lines are connected to the fuel/oil pump drain, IGV actuator seal drain and the surge control valve. These go to a collector line that runs along the underside of the APU and then to the drain tank. The drain tank is installed on the access door 316AR. The drain line from the tank runs along the access door to the drain mast. At 200 kts air speed the air flow causes a suction at the exit from the drain mast.
This air flow across the drain mast causes a suction in the drain line. The suction produced is enough to remove the contents of the drain tank. A vent line between the drain mast and the drain tank ventilates the drain tank and lines. Exhaust muffler drain, turbine plenum drain and the load compressor cavity drain are are drained directly overboard through the mast.
All drains are collected at the 3 ports of the APU drain bracket. This bracket establishes the interface with the A/C APU drain system:
Drain lines are connected to the fuel/oil pump drain, IGV actuator seal drain and the surge control valve. These go to a collector line that runs along the underside of the APU and then to the drain tank. The drain tank is installed on the access door 316AR. The drain line from the tank runs along the access door to the drain mast. At 200 kts air speed the air flow causes a suction at the exit from the drain mast.
This air flow across the drain mast causes a suction in the drain line. The suction produced is enough to remove the contents of the drain tank. A vent line between the drain mast and the drain tank ventilates the drain tank and lines. Exhaust muffler drain, turbine plenum drain and the load compressor cavity drain are are drained directly overboard through the mast.
All drains are collected at the 3 ports of the APU drain bracket. This bracket establishes the interface with the A/C APU drain system:
- the FWD port collects fuel, water and cleaning fluids,
- the MID port collects oil,
- the AFT port collects oil and fuel.
A. APU Drain System
All components of the APU drain system are installed on the R/H compartment access door 316AR. Metallic bellows form the interface with the APU drain bracket. When the access door is opened, the system separates at this interface.
The drain mast, attached to the door, is positioned far enough behind the APU air intake to prevent the intake ingesting the drained fluids.
All components of the APU drain system are installed on the R/H compartment access door 316AR. Metallic bellows form the interface with the APU drain bracket. When the access door is opened, the system separates at this interface.
The drain mast, attached to the door, is positioned far enough behind the APU air intake to prevent the intake ingesting the drained fluids.
- Drains from the forward and center APU drain ports are led directly overboard via separate drain lines to the drain mast.
- Drains from the aft APU drain port are lead to a drain tank. From there a drain and a vent line lead to the drain mast.
4. Operation
A. APU Drain System
On the ground, cold drains (oil + fuel) are collected in the drain tank. In flight (APU in operation or not) above 200kts forward air speed, sufficiently low pressure is generated at the drain mast to permit discharging of the drain tank contents through the suction line.
Hot and/or pressurized waste fuel is drained directly overboard.
Rain and cleaning fluids are collected separately and also drained directly overboard.
On the ground, cold drains (oil + fuel) are collected in the drain tank. In flight (APU in operation or not) above 200kts forward air speed, sufficiently low pressure is generated at the drain mast to permit discharging of the drain tank contents through the suction line.
Hot and/or pressurized waste fuel is drained directly overboard.
Rain and cleaning fluids are collected separately and also drained directly overboard.
B. APU Compartment Drainage
Rain or cleaning agents may enter the compartment through the ventilation louver. These and any oil and fuel in the compartment due to leaks or spillage during APU servicing are drained to the lowest point of the door and from there through the drainmast overboard.
Rain or cleaning agents may enter the compartment through the ventilation louver. These and any oil and fuel in the compartment due to leaks or spillage during APU servicing are drained to the lowest point of the door and from there through the drainmast overboard.