Air - Component Location (Details from Sht 2)
Figure 102 (Sheet 3)
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A / PW4000 SERIES /
747-400 / ENGINES /FAULT ISOLATION/MAINT MANUAL ////////////////////////
HPC SECONDARY INTERMEDIATE
FLOW CONTROL CASE
VALVE AND (REF)
TVBCA VALVE
INTERMEDIATE SOLENOID
CASE
(REF)
FWD
2.5 BLEED VALVE ACTUATOR FWD
F
E HPC SECONDARY FLOW CONTROL VALVE AND
INTERMEDIATE IDG AIR/OIL HEAT STABILITY BLEED CASE (REF) EXCHANGER VALVE PNEUMATIC RELAY OVERRIDE SOLENOID
VALVE
INTERMEDIATE CASE (REF)
NO. 3 BEARING BUFFER AIR COOLER IDG AIR/OIL HEAT EXCHANGER
2.9 BLEED VALVE OVERRIDE FWD
VALVE PRESSURE SWITCH
SOLENOID
EEC
(REF)
SPEED
G
TRANSDUCER
(N1) (REF)
FWD
H
INTERMEDIATE CASE (REF)
FWD
I
Air - Component Location (Details from Sht 2) Figure 102 (Sheet 4)
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A / PW4000 SERIES /
747-400 / ENGINES /FAULT ISOLATION/MAINT MANUAL ////////////////////////
FWD
PS3 AIR
FILTER
SEE R
LEFT TURBINE SHT 6
VANE AND BLADE FWD
COOLING AIR (TVBCA)
VALVE J FROM SHT 2
LEFT
2.9 BLEED VALVE
PNEUMATIC MANIFOLD (REF) K FROM SHT 2 2.9 BLEED VALVE RIGHT
FUEL/OIL COOLER (REF)
LEFT HPC SECONDARY FWD PS3 AIR
FLOW CONTROL VALVE FILTER SEE R
L FROM SHT 2 FWD SHT 6
TURBINE CASE
COOLING AIR VALVE
FROM SHT 3 CONTROL CABLE
M
TURBINE CASE COOLING AIR VALVE ACTUATOR
FWD N FROM SHT 3
Air - Component Location Figure 102 (Sheet 5)
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A / PW4000 SERIES /
747-400 / ENGINES /FAULT ISOLATION/MAINT MANUAL ////////////////////////
RIGHT HPC SECONDARY
INTERMEDIATE FLOW CONTROL VALVE
CASE (REF)
BELLCRANK
(REF)
FUEL PUMP (REF) FUEL FLOW TRANSMITTER (REF) O FWD FUEL METERING UNIT (REF) FROM SHT 3 VARIABLE STATOR VANE ACTUATOR FWD P FUEL FLOW TRANSMITTER (REF) FROM SHT 3 HEAD
MAIN FUEL SUPPLY LINE (REF)
TURBINE VANE COOLING AIR TUBE TVBCA VALVE POSITION SWITCH RIGHT TVBCA VALVE ELEMENT FILTER
FWD CASE
Q FROM SHT 3 R FROM SHT 5
Figure 102 (Sheet 6) Air - Component Location
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ENGINE BEARING COOLING SYSTEM - DESCRIPTION AND OPERATION
_________________________________________________________
1. General (Fig. 1)
_______
A. The engine bearing cooling system includes bearing carbon seal
pressurization and the No. 3 bearing cooling system.
B. The main bearing carbon seals are pressurized by compressor air to make sure that oil does not go into the air stream. The No. 1 and 2 bearing carbon seals are pressurized by low pressure compressor (LPC) bleed air. The No. 1.5 bearing carbon seals are pressurized by 9th-stage high pressure compressor (HPC) bleed air. The No. 3 bearing carbon seals are pressurized by cooled 12th-stage HPC bleed air. The No. 4 bearing carbon seal is pressurized by LPC air that goes into the low pressure turbine (LPT) shaft forward of the No. 1 bearing. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：747-400 AMM 飞机维护手册 大气 AIR 1(8)
