POWER PLANT
18-14
For Training Purposes Only
May 03
P I L O T T R A I N I N G G U I D E
Engine Starting System
Description
The starting system consists of the starter control valve and the air turbine starter
(ATS). The air turbine starter drives the accessory gearbox, which in turn drives the N
2
core section. DC electrical power and air from the 10th-stage bleed air manifold are
required to open the starter control valve and engage the air turbine starter.
The 10th-stage bleed air manifold can be pressurized by the:
•
APU
•
external air cart
•
10th-stage bleed air from the operating engine (crossbleed)
The following minimum bleed air pressures should be available for an engine start:
•
APU - 40 psi
•
External air start cart - 45 psi
•
Engine crossbleed - 60 psi (approximately 85% N
2
).
L(R)10th-stage bleed air manifold pressure is displayed on the EICAS status page.
During an engine crossbleed air start, ensure that intake
and exhaust areas of the operating engine are secure. When
starting engines in close quarters, consideration should be
given to the effects of jet blast.
Starting System - Schematic
Figure 18-8
CAUTION
10th-
STG
10th-
STG
10th
ISOL
L 10th
SOV
R 10th
SOV
LCV
L ACU
R ACU
APU
L ACU
R ACU
External
Air Source
P604_18_003
ATS
ATS
Starter
Control
Valve
Starter
Control
Valve
