(1)  
The front drain system includes nine drains installed on the two sides of the engine. Their drain outlets are installed together at a drain collector on the bottom center of the engine below the main gearbox.

 (2)  
The rear drain system includes one drain line on the left side of the engine. Its drain outlet is installed at a hole in the left core cowl.

 B.  
The engine vent system includes the thermal relief vent for the IDG.
 This vent permits the hot air to be bled overboard.

 C.  
There are nine fittings with caps on them in the front drain system which are used as fluid traps. These fluid traps are used to isolate the source of the leakage when fluids drain from the drain collector.

 2.  Component Details (Fig. 2)
_________________
 A.  The front drain system includes the drains that follow.
 (1)  
Strut Drain

 (a)  This drain collects the fluid from the left/right side fireseal, the main strut and the left/right side strut raceway.

 (2)  
Oil Seal Drain for the Fuel Pump Drive

 (3)  
Drain for the Shutoff Valve of the Turbine Case Cooling Air, Actuator for the Variable Stator Vane, and Air/Oil Heat Exchanger Valve for the IDG

 (a)  
All of the components above have an isolated fitting with a cap in the drain line but the actuator for the variable stator vane.

 (b)  
The fittings with a cap in the drain line are used as fluid traps to isolate the source of the leakage.

 (4)  
Oil Seal Drain for Hydraulic Pump Drive

 (5)  
Oil Seal Drain for the Starter Drive

 (a)  This drain line has a fitting with a cap in the line to be used as a fluid trap to show if this component has leaks.

 (6)  
Oil Seal Drain for the Electronic Engine Control (EEC) Alternator Drive

 (a)  This drain line has a fitting with a cap in the line to be used as a fluid trap to show if this component has leaks.

 (7)  
Oil Seal Drain for the Integrated Drive Generator (IDG) Drive

 (8)  
Fuel/Oil Cooler Drain

 (a)  
This drain collects the fluids from the Fuel/Oil Heat Exchanger for the IDG, the Bypass Valve for the Fuel/Oil Cooler, the Front Engine Fuel/Oil Cooler and the Rear Engine Fuel/Oil Cooler.

 (b)  
The section of this drain for the fuel/oil heat exchanger of the IDG and the bypass valve for the fuel/oil cooler has a fitting with a cap. This fitting is used as a fluid trap to isolate the source of the leakage.

 (c)  
The section of this drain for the front and rear engine fuel/oil cooler has a fitting with a cap. This fitting is used as a fluid trap to isolate the source of the leakage.

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Drains and Vents System Schematic
Figure 1

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DRAIN FOR THE DRAIN FOR THE IDG DRIVE OIL TURBINE CASE COOLING SEAL AIR VALVE ACTUATOR, VARIABLE
FWD
STATOR VANE ACTUATOR, AND IDG AIR/OIL HEAT EXCHANGER
A VALVE
Engine Vents and Drains
Figure 2 (Sheet 1)

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////////////////////////A / PW4000 SERIES /747-400 / ENGINES /MAINTENANCE MANUAL ////////////////////////
RIGHT THRUST REVERSER (REF) OVERBOARD DRAIN PORT
OVERBOARD DRAIN LINE
STRUT OVERBOARD DRAIN FLUID COLLECTOR
　
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