CREW ALERTING SYSTEM (CAS)
The Crew Alerting System (CAS) provides
the crew with information on system status and
abnormal conditions that may exist in the fuel
system such as low fuel pressure to the engine,
clogged filters, failed pumps, etc. (Table 5-1).
Low fuel pressure to the left or right engine
(L or R FUEL PRESS LOW) is the only fuel
system message that is in the warning group.
This malfunction will be annunciated by il-
lumination of the L or R FUEL PRESS LOW
light on the Crew Warning Panel (CWP)
(Figure 5-8).
The fuel quantity computer provides signals
to the CAS for messages on fuel imbalance and
low fuel quantity. A fuel imbalance message
is generated if the wing tanks become unbal-
anced by 500 pounds when the flaps are up,
or 200 pounds when the flaps are not up. The
Master Caution light will flash, an amber CAS
message “FUEL IMBALANCE” will be dis-
played and an amber box will appear, around
the wing tank fuel quantity display of the wing
containing the least amount of fuel.
The Master Caution light and an amber CAS
message, “L or R FUEL QTY LOW” will be
generated if the fuel quantity computer de-
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
FlightSafety
international
5-9
FOR TRAINING PURPOSES ONLY
CAS MESSAGE
W
C
C
C
C
C
A
C
C
A
A
A
A
A
L R FUEL PRESS LOW
A
L R FUEL HEATER
L R FUEL FILTER
DEFUEL OPEN
FUEL IMBALANCE
L R FUEL QTY LOW
FUEL XFLO
L R FWSOV CLSD
L R FWSOV FAULT
L R FUEL HEATER
L R FUEL FILTER
L R FUEL QTY FAULT
FUEL XFLO OPEN
L R STBY PUMP ON
L R FUEL BAY LOW
Low pressure to engine fuel pump inlet (< 1 psi) (See Chapter 7).
Fuel/oil cooler failure – fuel too cold (See Chapter 7).
Defueling valve not closed.
Engine or airframe fuel filter impending bypass (ground).
Wing imbalance > 500# (200# w/flaps not up).
Wing low fuel < 350#
Wing fuel xflow fault, not full open/closed > 1.5 sec.
Engine FWSOV closed.
FWSOV not fully open or closed > 1.5 seconds.
Fuel/oil cooler has failed – fuel too hot (See Chapter 7).
Fuel filter on engine or airframe impending bypass (inflight).
Wing fuel crossflow valve open.
A
FUEL QTY FAULT
AHRS #1 input inoperative or fuselage probe is inop or invalid.
Power applied to standby fuel pump (manual or auto).
L/R Fuel bay collector low.
W = Warning C = Caution A = Advisory
TYPE
MSG
LOGIC SUMMARY
L or R CH fault, or loss of density compensation.
Effective: 45-195 and subsequent and
prior aircraft modified by SB 45-28-5.
Table 5-1. FUEL SYSTEM CAS MESSAGES
