Engine Flashcards
What kind of engines are on the CRJ?
2 General Electric, turbo-fan engines:
CF34-8C5B1
What does FADEC do?
Receives information from thrust levers and other controls to produce the required amount of thrust.
What is Maximum Continuous Thrust?
13,386lbs
Low pressure spool is comprised of?
N1 single stage fan connected to 4-stage low pressure turbine.
High pressure spool connected to what?
N2 10 stage compressor connected to 2 stage high pressure turbine.
How much thrust comes from the core? How much comes from the high bypass air?
20% from core
80% from bypass
How do the thrust reverser work?
They deflect the bypass air forward.
What is FADEC?
Full authority digital engine control
What does FADEC do?
Uses various input signals to maximize engine performance AND
Automates engine control
How does FADEC get it’s power?
Before start: electrical system
N2 greater than 50%: dedicated alternator
Can a FADEC overheat condition be controlled?
No, may need to shut down respective engine.
How many channels does FADEC have?
2
If 1 FADEC channel fails, how will you know?
“L/R FADEC FAULT 1 or 2” status message
If both FADEC channels fail, how will you know?
Primary Page lacks indications from respective engine
“L/R FADEC” caution
N2 Gauge will have a white ARC when?
Wing Anti-Ice is on. Keeping N2 in the GREEN will ensure adequate bleed air for the anti-ice system.
“HOT” on ITT indicates what?
ITT during engine start exceeded 815 degrees celsius
ITT
Inter-turbine temperature
How many probes and where are they that make up the ITT system?
5 probes, Exit of the high-pressure turbine section
How many sensors are there for Vibration Monitoring in each engine?
2, one N1, the other N2
Is N2 vibration displayed?
No, but if N2 vibration exceeds 1.1 MILS “VIB” amber icon will display
Oil pressure gauges are removed whenever oil pressure rises above _________ PSID and are replaced by _________.
25; N1 vibration indicators
Describe how the thrust lever changes engine power.
Thrust lever sends signals to FADEC, FADEC signals FMU and the FMU changes the amount of fuel delivered to the combustion chamber
What will happen if a thrust lever fails?
“THROTTLE 1” Caution
FADEC will remain at last setting until Flaps are extended for the approach.
Where is the thrust lever mode displayed?
Below N1 on the primary EICAS display.
What does MCT mean below N1?
Maximum continuous thrust… Thrust levers are in CLIMB detent and APR is active or the HIGH PWR schedule switch has been selected ON
Where is the N1 needed to obtain the set thrust mode indicated?
Above the digital N1 indication
What is the purpose of a thrust flex takeoff?
Reduces fuel consumption
Better for the engines
APR
Automatic Performance Reserve
What does APR do
Monitors for loss of engine power during takeoff and approach.
When does APR arm?
Takeoff: both N1 reach 8% of N1 takeoff reference for 5 minutes
Approach: automatically when either engine available and: flaps greater than 20 degrees OOORRRR Landing Gear Extended
Manually: MAX POWER detent on thrust levers
if uncommanded APR activation occurs, what will happen?
“APR CMD SET” caution
How do thrust reversers work?
When initiated, hydraulic actuators move translating cowls aft, uncovering cascade vanes which redirect bypass air forward around the exterior of the engine.
What powers the thrust reverser actuators?
Engine 1 = Hydraulic 1
Engine 2 = Hydraulic 2
“REV” icon means what?
Uncomanded thrust reverser activation