Master Cautions

Question 1

L DC GEN

R DC GEN

Answer 1

Trigger: Generator line contactor is open

Possible Cause: Generator is offline

Note: See electrical section for line contactor control details

Question 2

L FUEL QTY

R FUEL QTY

Answer 2

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.

Question 3

L COL TANK LOW

R COL TANK LOW

Answer 3

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’

Question 4

STALL HEAT

Answer 4

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.

Question 5

BATTERY CHARGE

Answer 5

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.

Question 6

L FW VALVE

R FW VALVE

Answer 6

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).

Question 7

L GEN TIE OPEN

R GEN TIE OPEN

Answer 7

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.

Question 8

BAT TIE OPEN

Answer 8

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.

Question 9

L ENG ICE FAIL

R ENG ICE FAIL

Answer 9

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.

Question 10

L BK DI OVHT

R BK DI OVHT

Answer 10

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.

Question 11

HYD FLUID LOW

Answer 11

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.

Question 12

ANTI SKID FAIL

Answer 12

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).

Question 13

ANN PWR SOURCE

Answer 13

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).

Question 14

L FIRE LOOP

R FIRE LOOP

Answer 14

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).

Question 15

L PITOT HEAT

R PITOT HEAT

Answer 15

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.

Question 16

XFR VALVE FAIL

Answer 16

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.

Question 17

MAN STEER FAIL

If power steering installed

Answer 17

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

Question 18

L NO AUX XFR

R NO AUX TFR

Answer 18

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.

Question 19

AUTOFTHER OFF

Answer 19

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.

Question 20

PITCH TRIM OFF

Answer 20

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.

Question 21

AFX DISABLE

Answer 21

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.

Question 22

YD/RB FAIL

If autopilot NOT installed

Answer 22

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.

Question 23

RUD BOOST OFF

Answer 23

Trigger: Rudder boost system is off

Possible Cause: Rudder boost switch is in the OFF position