CRJ 900 Systems Review

ICE Caution: Ice has been detected and the wing/cowl anti-ice systems are not on. Both anti-ice cowl and wing need to be on to cancel this alert.

Ice Advisory: Ice has been detected and wing/cowl anti-ice systems are on. Message extinguishes if the probe no longer detects ice.

The difference between ICE Caution and Advisory

Fuel in the center tank is fed to the main wing tanks via transfer ejectors

Fuel is pumped to the collector tanks via gravity as the primary method and scavenge ejectors.

Fuel is pumped from the collector tanks to the engines via the main ejectors

Fuel is pumped from the left collector tank to the APU via the APU pump.

How does fuel move through the different tanks?

Fuel system computer

Only one channel is active at a time. If one system fails, the other will take over.

A dual channel ____ monitors and controls the operation of the fuel system

The ejectors operate by using motive flow pressure.

Motive flow is created when High-pressure fuel is passed through the venture-shaped nozzle of the ejector.

Motive flow

DC electric pumps that move fuel from the collector tanks to the engines; they are used to back up the main ejectors during engine start and when an ejector fails.

Pressing the boost pump switch light causes both pumps to operate when the fuel computer detects low fuel feed pressure in either feed manifold.

Boost pumps

A dedicated bi-directional pump that is used to move fuel between the wing tanks.

Pumps fuel from the wing tank with the higher quantity and moves it to the lower quantity tank.

xflow pump

DC powered pump that is installed at the left collector tank

APU Pump

Both the Main and APU batteries are required to start and operate the APU

The minimum battery voltage for both batteries is 22 volts

What is electrically required to start the APU pump

22 Volts

Voltage required on Main and APU batteries

PWR/FUEL Switchlight selected

P - fuel pump started

D - DOOR OPEN

I - IN BITE until intake door is fully open

G - Gauges displayed

S - SOV open

Start/stop Switchlight selected

Energizes the starter motor, APU START status message appears on the status page and the START light on the switchlight illuminates.

Fuel and ignition on at 5% RPM, APU start and acceleration

46%-60% rpm - ECU de-energizes the APU starter motor, APU START status message is removed and the switchlight START indication extinguishes.

At 95% RPM, ignition is de-energizes, APU SOV OPEN switchlight removed.

At 99% RPM+2 seconds, the green AVAIL switchlight illuminates.

EICAS indications APU startup - Ground - PDIGS

PWR/FUEL Switchlight selected

P - fuel pump started

I - IN BITE

G - Gauges displayed

S - SOV open

Start/stop Switchlight selected

Energizes the starter motor, APU START status message appears on the status page and the START light on the switchlight illuminates.

Fuel and ignition on at 5% RPM, APU start and acceleration

46%-60% rpm - ECU de-energizes the APU starter motor, APU START status message is removed and the switchlight START indication extinguishes.

At 95% RPM, ignition is de-energizes, APU SOV OPEN switchlight removed.

At 99% RPM+2 seconds, the green AVAIL switchlight illuminates.

EICAS indications APU Startup - Flight - PIGS

START/STOP switchlight selected

-Green AVAIL switchlight extinguishes

-APU Fuel shutoff solenoid closes

-APU intake door closes when RPM decreases below 25% RPM

APU PWR/FUEL switchlight selected

-APU RPM and EGT gauges are removed after approx. 10 seconds.

APU Shutdown sequence

APU pump draws fuel from the left collector tank and delivers fuel under pressure to the APU high pressure pump and fuel control unit.

If the APU pump fails, an internal bypass valve opens, allowing the accessory gearbox mounted high pressure pump to draw the fuel.

How does fuel get to the APU? What if that fails?

VHF COMM 1 and VHF COMM 2

What radios will be available if all AC power is lost?

IDG Low oil pressure or high oil temperature

IDG 1(2) Caution message

IDG 1(2) is disconnected automatically or manually

IDG 1(2) DISC status message

Amber: HOT/LOP

White: Engine is off or IDG is disconnected

IDG indications on AC Electrical Synoptic page

Green: 00-06

White: 07-14

Red: 15 and up. Over heat warning

BTMS Color logic

BTMS OVHT WARN RESET

We typically won’t be the ones to do this, unless the brakes have been inspected and MM01 entered, and MX simply forgot to reset it

What is used to reset the BTMS Overheat warn reset?

The manual DC motor will drive the outflow valve fully open.

EMER DEPRESS Caution message.

Aircraft will not let cabin pressure exceed 15,000 feet.

What valve does the EMER DEPRESS switchlight open

Red: Warning. Cannot be boxed.

Yellow: Caution. Can be boxed.

Green: Advisory. Cannot be boxed.

White: Status. Can be boxed.

Different types of EICAS Messages and if they can be boxed