Master Warning System Flashcards
Describe the master warning system.
The master warning system provides aural and visual indications of aircraft equipment malfunctions and status conditions. The Prius EPIC system continuously monitors the aircraft systems. The master warning system continuously monitors the aircraft systems and generates aural and visual indications of any status change that may require crew attention.
Where are the master warning indications displayed?
Indications are displayed on the engine indicating and crew alerting system (EICAS), the primary flight displays (PFDs), standby annunciations, or other. Ariosto lights and/or annunciations.
How many modular avionics units does the master warning system use?
The aircraft avionics system uses four modular avionics units (MAU). MAUs 1 and 4 contain the monitor warning system (MWS) required for master warning processing. The MWS receives information from the aircraft systems, processes the information, and then determines the required crew alerting system (CAS) messages in the EICAS window.
How many MAUs are in the aircraft?
Four.
Where are the MAUs found?
MAUs 1 and 2 - nose avionics compartment.
MAUs 3 and 4 - above the baggage compartment.
Describe the function of the MAUs:
Each MAU receives, processes, and communicates information across an avionics standard communication bus (ASCB).
Function of MAUs 1 and 4?
To process and post CAS messages.
Function of MAUs 2 and 3?
To illuminate the MASTER WARNING and MASTER CAUTION buttons and activate aural alerts as commanded by MAUs 1 and 4.
EICAS display:
The EICAS display is divided into fictional areas separated by flow bars.
The EICAS displays aircraft system status.
Aircraft system status is displayed in digital and/or analog format.
EICAS display colors
Green : normal operating limits.
Amber: outside normal operating limits. (Caution) parameter)
Red: Outside normal operating limits (exceedance).
White: Information only.
Master warning buttons:
Flash when activated by a red CAS message.
Continue to flash even if the condition automatically clears. Once activated, the buttons must be pushed (reset) to extinguish.
Activation is accompanied by a double chime or voice warning.
Master caution lights:
Illuminate steady when activated by an amber CAS message.
Extinguish if the activating condition clears itself.
Extinguish when the button is pressed.
Activation is accompanied with a single aural chime.
Invalid data
Amber dashes replace numeric values when data is invalid.
Invalid data normally appears following sensor failure.
Which bus are the standby annunciations powered from?
The emergency bus.
STANDBY ANNUNCIATORS:
GEN OFF
Annunciator illuminates with a loss of all engine-driven generator power.
The DC GEN OFF L-R APU CAS message accompanies this annunciator.
STANBY ANNUNCIATORS:
OIL PRESS L-R
The respective engine oil pressure is below 20psi.
This annunciation results from a differential pressure switch and is independent of the EICAS oil gauging system.
The OIL PRESSURE LOW L-R CAS message accompanies this annunciator.
STANBY ANNUNCIATORS:
STAB NO TAKEOFF
On ground, the horizontal stabilizer is not in takeoff range and one or more throttles have been advanced to the TO detent. The annunciator illuminates only on the ground with a throttle advanced above the CRU detent. This message is triggered from a separate set of contacts and is a backup to the stabilizer trim indications on the EICAS.
STANBY ANNUNCIATORS:
FUEL LOW L-R
Respective fuel tank level has 540 +/- 60 pounds of usable fuel.
Message is triggered by a float switch in the respective fuel tank.
The annunciator is independent of the fuel gauging system shown on the EICAS.
The FUEL LEVEL LOW L-R CAS message accompanies this annunciator.
This annunciator is intended to act as a fuel low level backup to the EICAS fuel indications.
NO TAKEOFF CAS MESSAGE
Displayed on the ground only when one or more of the NO TAKEOFF conditions has been detected with the engines running and throttles in or past the CRU detent.
If takeoff is continued, the MASTER WARNING and aural alert will stop at 80 KIAS. The message will clear upon liftoff.
NO TAKEOFF ITEMS (11)
- Cabin door open.
- Parking brake is on.
- Pitch Roll Disconnect is engaged.
- Flaps are not in takeoff configuration.
- SPEEDBRAKE handle is not stowed.
- Gust lock is ON.
- Stabilizer, aileron, or rudder trim not in the takeoff band.
- Parking brake pressure is low.
Aileron ratio changer is not in takeoff position. - Rudder bias actuator is not in the takeoff position.
- Thrust reverser emergency stow is engaged.
