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The EEC will reset (in preparation for the next engine start) after ENGINE RUN
switch has been selected to OFF.
MAX
THRUST
IDLE
REV
MAX REV
ENG
RUN
OFF OFF
L R
GX_17_070
ENG
RUN
OFF OFF
L R
GX_17_071
17-48 For Training Purposes Only
Sept 04
P I LOT T R A I N I N G GU I D E
POWER PLANT
DRY CRANKING
Dry cranking of the engine is accomplished as follows:
• Ensure ENGINE RUN switch is selected to OFF
• Ensure IGNITION switch is Normal (the EEC will inhibit IGNITION when
CRANK is selected, unless IGNITION has been selected to ON)
• Select START SELECTOR to L CRANK or R CRANK
The EEC will open the SAV and activate the starter motor (if N2 below starter
reengagement speed). The EEC will keep the starter motor operating as long as the N2
is below starter disengagement speed (approximately 45% N2), for 3 minutes
maximum.
The crew can stop cranking by selecting START SELECTOR to AUTO.
WET CRANKING
Wet cranking is normally performed by maintenance personnel.
Wet cranking of the engine is accomplished as follows:
• Ensure IGNITION switch is Normal (the EEC will inhibit IGNITION when
CRANK is selected, unless IGNITION has been selected to ON)
• Select START SELECTOR to L CRANK or R CRANK
• Select ENGINE RUN switch to ON (HPSOV opens allowing fuel to the engine
burners)
The EEC will open the SAV and activate the starter motor (if N2 below starter
reengagement speed). The EEC will keep the starter motor operating as long as the N2
is below starter disengagement speed (approximately 45% N2), for 3 minutes
maximum.
GX_17_072
ENGINE
ENG START
IGNITION
ON
AUTO
L CRANK R CRANK
ENG
RUN
OFF OFF
L R
ENGINE
ENG START
IGNITION
ON
AUTO
L CRANK R CRANK
ENG
RUN
OFF OFF
L R
GX_17_073
For Training Purposes Only
Sept 04
17-49
P I LOT T R A I N I N G GU I D E
POWER PLANT
STARTING ANOMALIES
AUTOMATIC GROUND START ABORT
Any of the following events will result in an automatic ground start abort:
• Crew selecting ENGINE RUN switch to OFF
• N2 speed not greater than or equal to 15% (120 seconds from ENGINE RUN
switch ON)
• Idle speed not achieved (120 seconds from HPSOV open)
• Starter cutout not being reached within starter duty timer (180 seconds from SAV
open)
• ITT exceeding the ground start limit (700°C) after light-off and during acceleration
to Idle
MANUAL GROUND START ABORT
Any of the following events will result in a manual ground start abort:
• Crew selecting ENGINE RUN switch to OFF
• Crew selecting the START SELECTOR switch to AUTO
• Crew selecting the IGNITION switch to Normal
AUTOMATIC AIR START ABORT
Any of the following events will result in an automatic air start abort:
• Crew selecting ENGINE RUN switch to OFF
• N2 speed not greater than or equal to 15% (60 seconds from ENGINE RUN switch
ON)
• Idle speed not achieved (600 seconds from HPSOV open)
• Starter cutout not being reached within inflight starter duty timer (180 seconds
from SAV open)
17-50 For Training Purposes Only
Sept 04
P I LOT T R A I N I N G GU I D E
POWER PLANT
AUTO-RELIGHT
The EEC provides an Auto-Relight function to detect and recover an engine flameout.
The Auto-Relight function is enabled when the engine is at or above Idle and the
ENGINE RUN switch is ON.
Two methods are used to detect a flameout at all engine speeds at or above Idle:
• By monitoring the rate of change of N2. The threshold for the rate of change is
calculated as a function of HP compressor pressure exit (P30) and altitude. A
flameout is assumed to have occurred if N2 decelerates at a rate greater than this
threshold
• By monitoring the difference between commanded Idle N2 and actual N2. If the
difference is greater than a preset threshold, a flameout is assumed to have
occurred. This method is suppressed for 15 seconds, following a transition from
low idle to high idle
When a flameout is detected, the EEC will energize both igniters and schedule fuel
flow until the engine relights. The igniters are energized for 20 seconds after an engine
relight.
If the engine continues to run down (no relight), then the EEC will close the HPSOV at
35% N2 and deenergize the igniters and an EICAS message is posted.
QUICK RELIGHT
The EEC provides a Quick Relight function which automatically relights the engine if
　
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