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AUTOMATIC PERFORMANCE
RESERVE (APR)
The APR system provides for an automatic in-
crease in thrust on the operative engine in the
event of power loss on the other engine during
takeoff. This reserve power can be applied au-
tomatically if the APR is armed or it can be ob-
tained manually by placing the thrust lever(s)
full forward to the APR position.
The system consists of the DEEC (APR soft-
ware), a two position pushbutton switch on the
engine/fuel control panel, labeled APR, lo-
cated next to the ENG SYNC switch (Figure
7-19) and, an APR position on the throttle
quadrant.
When the APR switch is depressed, the white
“ARM” illuminates in the switch and the DEEC
performs a software verification. If the APR
triggering circuit is armed for both engines, a
white “APR” annunciator will appear at the top
of the EICAS between the N1 indicators
(Figure 7-8). If the system verification fails,
a white “L/R APR FAULT” message will ap-
pear on the CAS (Table 7-4).
Once armed, if there is an N2 speed mismatch
of 15% or greater between the left and right
engines, the DEECs will increase fuel flow to
produce approximately a 2% increase in N1.
When activated, the color of the APR annun-
ciator on the EICAS will then turn from white
to green and annunciate “APR ON.” If APR is
activated with the thrust levers set at T/O,
thrust would increase approximately 150
pounds per engine. When APR is automatically
or manually activated, each DEEC will also in-
crease ITT limiting by 22° C to allow for the
increased thrust by 2% N1. The DEECs will
attempt to increase thrust on both engines
when APR is activated. However, if an engine
roll back caused the 15% split in N2, the mal-
functioning engine probably will not respond
to the DEEC command for increased thrust.
Once APR has been activated in the auto mode,
the APR arm switch must be cycled to off to
return to normal operation. If APR is inad-
vertently activated on the ground (i.e. if the
pilot uses differential thrust during taxi), cy-
cling the APR switch off and back to ARM
again, with the N2 rpm’s matched within 15%,
will reset the system.
Performance reserve may be selected manu-
ally by advancing either or both thrust levers
to the APR position even when the APR switch
is not in the ARM position. The green “APR
ON” annunciator on the EICAS will also il-
luminate with a manual activation.
ENGINE VIBRATION MONITOR
An engine vibration sensor is mounted on each
engine. If the sensor detects engine vibration
in excess of the preset level, a white “L/R
ENG VIB MON” advisory CAS message will
be displayed on the EICAS (Table 7-4).
ENGINE DIAGNOSTIC SYSTEM
(EDS)
The DEECs each contain embedded trend mon-
itoring software which provides data for the
Engine Diagnostic System (EDS). This data
can be downloaded for Engine Condition Trend
Monitoring (ECTM).
The DEEC continuously monitors the neces-
sary parameters and events during engine op-
eration and periodically stores the required
information in memory located within the
DEECs. At specified intervals, the data stored
within the DEEC memory is downloaded by
maintenance personnel.
The DEEC will generate a white “L or R
CHECK EDS” CAS message if the corre-
sponding EDS has lost power, EDS built-in-
test (BITE) has detected a system failure, the
EDS memory is 85% full, or the system has de-
tected an engine condition which is out of ac-
ceptable parameters.
All faults identified by the EDS will be stored
in non-volatile memory with a time stamp
added. The pilot has the capability to highlight
or identify points in the stored data by mo-
L E A R J E T 4 5
P I L O T T R A I N I N G M A N U A L
7-28
FOR TRAINING PURPOSES ONLY
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