Master Cautions Flashcards
L DC GEN
R DC GEN
Trigger: Generator line contactor is open
Possible Cause: Generator is offline
Note: See electrical section for line contactor control details
L FUEL QTY
R FUEL QTY
Trigger: Fluid Level Sensor is detecting less than 324 lbs of usable fuel
Possible Cause: Fuel quantity is below 324 lbs of usable fuel
Note: Fluid Level Sensor has a built-in 5 second delay prior to activation.
L COL TANK LOW
R COL TANK LOW
Trigger: Fluid Level Sensor is detecting less than 53 lbs of usable fuel in the
collector tank
Possible Cause: Fuel system collector tank below 53 lbs of usable fuel
Note: Remaining fuel is approximately 8 minutes if configured for normal
cruise at 160 knots and 10,000’
STALL HEAT
Trigger: Insufficient current being supplied to the stall heat transducer
Possible Cause: Insufficient current to provide enough heat on stall warning
transducer to prevent icing
Note: System only detects if there is insufficient heat to prevent ice in ground
mode. There is NO warning system for insufficient heat during flight mode
and a failure can only be identified by visual means. Annunciator also
illuminates if the Stall Heat switch is in the OFF position.
BATTERY CHARGE
Trigger: Battery charge rate is > 6 amps for > 7 seconds
Possible Cause: Excessive charge rate on battery, monitor for thermal
runaway (see Electrical Section for details)
Note: This annunciator normally illuminates after engine starts and must be
monitored for a decreasing charge rate. Annunciator extinguishers when
charge rate is < 6 amps.
L FW VALVE
R FW VALVE
Trigger: Firewall fuel valve has not reached its selected position
Possible Cause: Firewall fuel valve has not reached its selected position
Note: When the Firewall Fuel Valve is opened or closed the respective L/R FW
VALVE annunciator should blink quickly (not long enough however to trigger
the Master Caution Flasher).
L GEN TIE OPEN
R GEN TIE OPEN
Trigger: Generator bus tie is open
Possible Cause: L/ R Generator bus tie HED has isolated the L/ R generator
bus from the center bus
Note: The respective Generator and Generator Bus have been isolated from
the Center Bus, Battery Bus and opposite Generator Bus. Either triggered by
the respective HED(s) or the generator ties have been manually opened. See
Electrical System and Abnormal Procedures checklist for details.
BAT TIE OPEN
the respective HED(s) or the generator ties have been manually opened. See
Electrical System and Abnormal Procedures checklist for details.
Trigger: Battery bus tie is open
Possible Cause: Battery tie HED has isolated the battery from the center bus
Note: The Battery is no longer being charged. The battery is still powering any
items on the battery bus and hot battery bus.
L ENG ICE FAIL
R ENG ICE FAIL
Trigger: Disagreement between switch position and ice vane position.
Possible Cause: Ice vane has not reached its selected position within 30
seconds.
Note: If neither actuator will correct the problem, the crew must consider
flight conditions for potential icing as well as the effect on aircraft
performance.
L BK DI OVHT
R BK DI OVHT
Trigger: Warning line tubing pressure sensed at < 1.5 ± 0.5 PSI
Possible Cause: Melted or failed brake de-ice failure warning line or system is
turned off.
Note: Nominal pressure in warning line (EVA tubing) is 17.5 – 19.0 PSI. Both
annunciators also illuminate if both ENVIRO switches are placed in the INST &
ENVIRO OFF position.
HYD FLUID LOW
Trigger: Fluid Level Sensor is detecting a low quantity of hydraulic fluid in the
reservoir.
Possible Cause: Landing gear hydraulic fluid level low.
Note: Fluid Level Sensor has a built-in 5 second delay prior to activation.
ANTI SKID FAIL
Trigger: Anti-skid Computer Failure.
Possible Cause: Anti-skid computer electrical fault or low hydraulic oil
pressure in the antiskid brake system.
Note: Anti-skid should be selected OFF and normal performance charts from
the AFM shall be used for all calculations (These charts assume the anti-skid
system is not installed).
ANN PWR SOURCE
Trigger: Loss of power to one or both of the power sources that supply the
sensors that trigger certain annunciators.
Possible Cause: Annunciator sensors power supply failure.
Note: The annunciator bulbs are not affected by this failure and will test
successfully, but the sensors that trigger certain annunciators may not work.
(See Annunciators Section and B1900D MEL for details).
L FIRE LOOP
R FIRE LOOP
Trigger: Fire detection loop continuity monitoring has failed.
Possible Cause: Fire detection loop is broken in one or more places.
Note: The fire detection system may no longer be able to detect an engine
fire (See Fire Protection for Details).
L PITOT HEAT
R PITOT HEAT
Trigger: Insufficient current being supplied to the pitot-static mast
Possible Cause: Insufficient current to provide enough heat on pitot-static
mast to prevent icing.
Note: Annunciator also illuminates if the pitot switch is in the OFF position.
XFR VALVE FAIL
Trigger: Disagreement between switch position and valve position
Possible Cause: Fuel transfer valve has not reached the selected position
within 2 seconds
Note: See Fuel System and Abnormal Procedures Checklist: Transfer Valve
Failure for details.
MAN STEER FAIL
If power steering installed
Trigger: Disagreement between switch position and power steering actuator
position
Possible Cause: Power steering system actuator has not returned to free
caster mode
Note: Nose wheel won’t free caster with power steering dis-engaged
L NO AUX XFR
R NO AUX TFR
Trigger: Pressure sensed in fuel line between Aux tank to collector tank is < 5
PSI
Possible Cause: Switch in AUTO position; indicates a failure of the float valve
to shutoff the aux pump. Switch in ON position; indicates that the tank is
either empty or the aux pump has failed.
AUTOFTHER OFF
Trigger: Autofeather switch is in the OFF position and the left main landing
gear is fully not retracted.
Possible Cause: Autofeather system turned OFF with landing gear selected
down
Note: Autofeather must be armed for take-off, climb, approach and landing.
The exception to this is when on a single-engine approach this annunciator
will illuminate and should be acknowledged and left OFF.
PITCH TRIM OFF
Trigger: Trim system has been de-energized by either yoke disconnect switch
and the pitch trim switch is ON.
Possible Cause: Trim system has been de-energized by either yoke disconnect
switch and the pitch trim switch is ON.
AFX DISABLE
Trigger: Autofeather system logic has disabled the autofeather capability
Possible Cause: Autofeather system is not capable of feathering the
propellers
Note: System logic prevents feathering both propellers at the same time
and/or prevents feathering the propeller on the good engine following an
engine failure.
YD/RB FAIL
If autopilot NOT installed
Trigger: Failure of the Yaw damper/Rudder Boost computer
Possible Cause: Yaw Damp/Rudder Boost computer has failed
Note: Crew may re-engage Yaw damper after selecting the opposite
computer.
RUD BOOST OFF
Trigger: Rudder boost system is off
Possible Cause: Rudder boost switch is in the OFF position
