Endeavor CRJ900/700 SYSTEMS
(workbook) Powerplant, Fuel, Fire
What does the N1 section consist of? - 28-blade titanium fan
4 stage low pressure turbine
What does the N2 section consist of? - 10 stage axial compressor
2 stage high pressure turbine
What is the normal takeoff thrust? - 13,600 lbs/ 14,510 with APR
Describe how the engine operates through the following stages; Intake,
Compression, Combustion, Exhaust - Comes in through N1 section, most bypassed,
compressed in 10 stage axial flow compressor (N2), annular combustion chamber, 2
stage high pressure turbine (drives N2) then 4 stage low pressure turbine (drives
N1), finally exhaust
What percentage of engine air is bypass, and what percentage is core air? - 85%
bypass, 15% core
What is different about the first four stages of the N2 compressor section? - FADEC
controlled variable geometry
Describe the function and actuation of the Variable Geometry System - High
pressure fuel is used to physically move the stators and inlet guide vanes to prevent
compressor stalls and surges (FADEC controlled)
How is the position, of the Variable Geometry System, controlled? - FADEC via high
pressure fuel
Describe the function of the Operability Valve - Relieves pressure in the system to
prevent compressor stall/surge
What actuates the Operability valve? - FADEC using high pressure fuel from the fuel
control unit
Which components are located on the Accessory Gear Box (AGB) 900SM 22-3 - 3
PUMPS: Hydraulic pump, Fuel pump, Engine lubrication Oil pump
2 ELEC: IDG, FADEC Alternator
1 AIR Turbine Starter.
From which compressor stages do we receive bleed air, and for what purposes? - 6
th stage low pressure and 10 th stage high pressure into the common bleed manifold
for ECS (Environment Control System), Anti-Ice, and Engine Starts.
How many igniters exist in the combustion section, and what are their power
sources?
Are igniters AC or DC? - 2 igniters
, A: AC Ess Bus
B: DC Batt Bus (converts to AC)
Igniters are AC only
How can the Battery bus be the power source of Ignition B when both igniters use
AC power? - Channel B includes an Inline Static Inverter to create the needed AC
power.
It just so happens that during a battery start, Ignition A is the active ignition. How will
you be able to start the engine? - After 15 seconds FADEC will realize the igniter
isn't powered and will switch to the other channel, in this case channel B
What happens when continuous ignition is selected, and when is it required? - Both
igniter channels will fire at a higher setting than normal start continuously. It is
required for TO and Landing on Contaminated Runways. In moderate or higher
turbulence. In moderate or higher Rain and in the vicinity of thunderstorms
When would the FADEC automatically engage Continuous Ignition? - Approach to
stall
Where is the probe located that gives us Inter-Turbine Temperature (ITT)
information? - Between the 2 stage high pressure turbine and the 4 stage low
pressure turbine
When will the FADEC be powered by its own alternator, and when will it rely on the
aircraft's electrical power? - Will use AC Power until 50% N2, then will switch to
FADEC Alt as the power source. If the FADEC Alt spins down (N2 below 50%) then
it will switch back to AC Power as needed
How many channels are on the FADEC, and what if the active channel fails? - 2
channels per FADEC, if the active fails it will automatically switch to the other
channel as a backup
When will the active FADEC channel switch during normal operations? - Each
successive engine start at around 7% N2
When will the FADEC command a shut-down of the engines? - 3 overspeed
conditions in a row within a certain amount of time, a Hot start or a Hung start
T/F, the thrust levers are mechanically connected to the Fuel Metering Unit: - False
What would occur if the L or R FADEC failed completely? - You would lose control of
the engine and could eventually flameout due to the lack of fuel control.
What is APR, and when would the FADEC command it? - APR is a small power
boost on the good or working engine(s) when an engine fails or when the thrust
levers command it. Commanded based on thrust lever position when asking for Max
Thrust or when in TOGA if there is a 15% split in N1 between engines.
(workbook) Powerplant, Fuel, Fire
What does the N1 section consist of? - 28-blade titanium fan
4 stage low pressure turbine
What does the N2 section consist of? - 10 stage axial compressor
2 stage high pressure turbine
What is the normal takeoff thrust? - 13,600 lbs/ 14,510 with APR
Describe how the engine operates through the following stages; Intake,
Compression, Combustion, Exhaust - Comes in through N1 section, most bypassed,
compressed in 10 stage axial flow compressor (N2), annular combustion chamber, 2
stage high pressure turbine (drives N2) then 4 stage low pressure turbine (drives
N1), finally exhaust
What percentage of engine air is bypass, and what percentage is core air? - 85%
bypass, 15% core
What is different about the first four stages of the N2 compressor section? - FADEC
controlled variable geometry
Describe the function and actuation of the Variable Geometry System - High
pressure fuel is used to physically move the stators and inlet guide vanes to prevent
compressor stalls and surges (FADEC controlled)
How is the position, of the Variable Geometry System, controlled? - FADEC via high
pressure fuel
Describe the function of the Operability Valve - Relieves pressure in the system to
prevent compressor stall/surge
What actuates the Operability valve? - FADEC using high pressure fuel from the fuel
control unit
Which components are located on the Accessory Gear Box (AGB) 900SM 22-3 - 3
PUMPS: Hydraulic pump, Fuel pump, Engine lubrication Oil pump
2 ELEC: IDG, FADEC Alternator
1 AIR Turbine Starter.
From which compressor stages do we receive bleed air, and for what purposes? - 6
th stage low pressure and 10 th stage high pressure into the common bleed manifold
for ECS (Environment Control System), Anti-Ice, and Engine Starts.
How many igniters exist in the combustion section, and what are their power
sources?
Are igniters AC or DC? - 2 igniters
, A: AC Ess Bus
B: DC Batt Bus (converts to AC)
Igniters are AC only
How can the Battery bus be the power source of Ignition B when both igniters use
AC power? - Channel B includes an Inline Static Inverter to create the needed AC
power.
It just so happens that during a battery start, Ignition A is the active ignition. How will
you be able to start the engine? - After 15 seconds FADEC will realize the igniter
isn't powered and will switch to the other channel, in this case channel B
What happens when continuous ignition is selected, and when is it required? - Both
igniter channels will fire at a higher setting than normal start continuously. It is
required for TO and Landing on Contaminated Runways. In moderate or higher
turbulence. In moderate or higher Rain and in the vicinity of thunderstorms
When would the FADEC automatically engage Continuous Ignition? - Approach to
stall
Where is the probe located that gives us Inter-Turbine Temperature (ITT)
information? - Between the 2 stage high pressure turbine and the 4 stage low
pressure turbine
When will the FADEC be powered by its own alternator, and when will it rely on the
aircraft's electrical power? - Will use AC Power until 50% N2, then will switch to
FADEC Alt as the power source. If the FADEC Alt spins down (N2 below 50%) then
it will switch back to AC Power as needed
How many channels are on the FADEC, and what if the active channel fails? - 2
channels per FADEC, if the active fails it will automatically switch to the other
channel as a backup
When will the active FADEC channel switch during normal operations? - Each
successive engine start at around 7% N2
When will the FADEC command a shut-down of the engines? - 3 overspeed
conditions in a row within a certain amount of time, a Hot start or a Hung start
T/F, the thrust levers are mechanically connected to the Fuel Metering Unit: - False
What would occur if the L or R FADEC failed completely? - You would lose control of
the engine and could eventually flameout due to the lack of fuel control.
What is APR, and when would the FADEC command it? - APR is a small power
boost on the good or working engine(s) when an engine fails or when the thrust
levers command it. Commanded based on thrust lever position when asking for Max
Thrust or when in TOGA if there is a 15% split in N1 between engines.
