N
1
(Fan) RPM
N
1
(fan) rpm (Figure 7-11) is sensed by a
monopole transmitter located on the engine
front frame. Electrical signals are sent via the
SDC to the appropriate analog and digital
scale. Each scale is calibrated to indicate a per-
centage of N
1
rpm from 0% to 100%.
ITT (Interturbine Temperature)
Thermocouples of different lengths are equally
spaced between the LP turbine and the HP
turbine. The thermocouples are parallel-con-
nected. The ITT output is sent to the appro-
priate vertical and digital scales of the ITT
indicator via the SDC. The ITT indicator scales
are calibrated in degrees Celsius from 0 to
1000°C.
A red light (Figure 7-11) above each verti-
cal scale will illuminate if the ITT reaches
899° C. These lights also illuminate during
the instrument test.
A two-position switch labeled “DGT OFF”
(Figure 7-11), located at the bottom of the ITT
panel, allows the crew to extinguish all engine
parameter digital displays which might be an-
noying on extended nighttime operations.
N
2
RPM
N
2
rpm (Figure 7-11) is supplied by an alter-
nator driven by the accessory gear. The rpm
signals are isolated from the alternator’s power
to eliminate interference and interruption. The
rpm signals are sent to the appropriate N
2
scales via the SDC.
Fuel Flow
Fuel flow (Figure 7-11) is sensed by a mass
flow transmitter located downstream of the
FCU. The transmitter output is sent to the
SDC for processing into analog and digital
readout for display on the appropriate fuel
flow indicators.
The analog scales are calibrated in pounds of
fuel per hour from 0 to 4,000. The digital dis-
plays are in pounds per hours times 10.
ENGINE STARTING
General
Engine starting is divided into ground starts,
starter-assisted airstarts, and windmilling airstarts.
Starter
The engine starter is an electrically controlled
air turbine starter (ATS). Starter output is ap-
plied through a clutch to the accessory gear
which, in turn, rotates the HP spool.
A speed sensor operated by the ATS governor
automatically terminates the starter cycle at
approximately 55% N
2
rpm. The average start
cycle is less than 40 seconds. A time-delay
relay is armed when a start cycle is initiated,
and, if the ATS operation continues for more
than 60 seconds, the time-delay relay will
open an illuminate the amber STOP switchlight
on the start and ignition control panel (Figure
7-8). The STOP switchlight may be pushed to
terminate the start sequence at any time below
55% N
2
rpm.
ATS Air Sources
The air source for ATS operation can be (1)
APU bleed air, (2) an external air source, or
(3) cross bleed from an operating engine. The
minimum air pressure for starting is 45 psi.
(See Chapter 9, “Pneumatics.”)
Ground Start (APU Air)
Engine starting should not be at-
t e m p t e d u n t i l t h e Wa l k a r o u n d
checklist and the Cockpit checklist
are completed.
To initiate a ground start using APU bleed
a i r, p u s h t h e A P U b l e e d - a i r s w i t c h l i g h t
(Figure 7-13). The OPEN light will illu-
minate, and the left scale of the bleed-air
p r e s s u r e i n d i c a t o r ( F i g u r e 7 - 1 4 ) s h o u l d
show approximately 50 psi. Push IGN A or
FlightSafety Canada
L t é e
L t d .
CL-600-2B16 PILOT TRAINING MANUAL
7-16
CL 601-3R
FOR TRAINING PURPOSES ONLY
WARNING