Engine (CF34-8E5) Flashcards
Engine Type
General Electric CF34-8E5
Engine Description
Hi-bypass, dual-rotor turbofan, 10-stage compressor with variable geometry/2-stage HP turbine
Max Thrust
13,800-14,200 lbs (RSV)
Engine Lubrication System
Each engine, IDG and the APU have their own independent systems
ATS
Air turbine starter
How many igniters per engine?
2
How can the engines be started?
APU air
Cross-bleed air (engine assist)
External air source (air cart or huffer cart)
Windmilling start (airborne only)
Engine Start Sequence
FADEC controlled
-For air starts FADEC ignores an “OFF” position selected on the ignition
Normal Start Sequence
N2 rotation 7% N2- Ignition 20% N2- Fuel Flow (Light-off within 5 sec) Normal acceleration and oil pressure 50% N2-Ignition off and starter cut-out Normal acceleration and stabilization
Thrust Reverser System
- Hydraulically actuated
- FADEC proved interlock protection against inadvertent deployment
- Idle thrust commanded if opened in flight
- Ground use only
- Idle thrust reverse is commanded while cowls are not totally deployed
Engine FADEC
- ESS powered below 50% N2
- PMA powered above approximately 50% N2
- 1 installed for each engine
- Each FADEC has 2 channels (active and standby)
ATTCS
Automatic T/O Thrust Control System
ATTCS controlled by?
FADEC
Under what conditions does the ATTCS automatically provide max engine thrust (RSV)?
-Armed, Thrust Levers TOGA and one of the following conditions occur
- Difference between N1 values >15%
- One engine failure during T/O
- One engine failure during Go-around
- Windshear detection
Is ATTCS automatically armed for normal go-around mode?
YES
FLEX
Flexible T/O
-Reduced thrust for takeoff based on assumed temperature
N1
-Target
Cyan tick
-Max N1 for selected engine thrust
N1
-Rating
Green tick
-Max N1 allowed for current thrust rating and current operating conditions
N1
-Request
Moving Arc
-Value requested based on TLA (Thrust Lever Angle)
TO-1
Takeoff
TO-1 RSV
Takeoff reserve
GA
Go-around
GA-RSV
Go-around reserve
CON
Max continuous thrust
CLB
Max climb thrust
CRZ
Max cruise
Idle
Idle
During engine start FADEC will prevent
- Hung start (inhibited in flight), compressor not accelerating to generate required airflow
- Hot start (inhibited in flight), insufficient airflow to keep ITT under control
- No light-off, air and fuel, but no igntion
If N2 reaches 102% the FADEC commands?
Automatic shutdown
In the event of 3 consecutive shuts downs do to overspeed within 30 seconds?
The FADEC will not attempt a relight
Overtemperture
FADEC will prevent fuel flow during ground start until ITT is at or below 120 C
Automatic dry motoring occurs and fuel flow is commanded with ITT below 120 C
What types of engines are on the E175?
General Electric CF-34-8E5
-Hi-bypass, 2-spool, axial-flow, turbo-fan
How much thrust do the engines produce?
13,800-14,200 lbs (ISA)
Describe N1 spool
Single-stage fan, 4-stage LP turbine
Describe N2 spool
10-stage compressor (gas generator, 2-stage HP turbine
How many igniters per engine?
2 per engine
How many igniters activate for engine start?
Ground- 1 igniter (switch in AUTO)
Flight- 2 igniters (switch in AUTO)
What happens when the ignition switch is selected to OVRD?
Activates both igniters on the ground or in flight
Can the igniters be turned off during flight?
The switch may be moved to the OFF position but the FADEC disregards the command
The OFF position is used for dry motoring on the ground only
What controls the engine?
2-channel FADEC (one channel active and one in standby as a backup)
Is only one FADEC channel used every flight?
No, they automatically alternate with each engine start
What does the cyan line on the N1 gauge represent during approach? When does it appear
The minimum N1 for bleed requirements in icing conditions
Configured for landing
What sources are available fore engine starting?
APU
Ground source (huffer cart or air bottle)
Opposite engine
Windmill start
Does the FADEC provide engine start protection?
Only on the ground for hot start, hung start or no light-off
What will the FADEC automatically do in case of a start on the ground?
FADEC will not allow FF if ITT >120 C
FADEC will automatically dry motor engine and introduce fuel when ITT
Describe the engine start sequence
Start switch momentarily to start: 7% N2 -- Ignition 20% N2 -- Fuel flow 20% N2+ 5 sec -- Light off 50% N2 -- Ignition off
Engine stabilizes
N1 -- 27% ITT -- 460 C N2 -- 62% FF -- 550 lbs/hr Oil Pressure -- >25 psi
What does WML mean on the engine indications?
Windmilling engine
-FADEC has detected a flame-out and is attempting an auto re-light or an assisted start has been commanded
What provides under-speed and over-speed protection?
The FADEC via FMU
-Approximately 52% N2 and 102% N2 respectively
What happens after 3 over-speed detection events?
FADEC will not re-light the engine
What heats the fuel and cools engine oil?
Fuel / Oil heat exchanger
What is ATTCS? What controls it?
Automatic Take-off Thrust Control System
- Provides max thrust reserve (RSV) according to current rate previously selected via the MCDU
- FADEC controlled
What will trigger an ATTCS event?
- N1 differences >15% between engines
- Engine failure during TOGA
- Windshear detection
When is thrust reverse available?
Weight-on-wheels (WOW)
What happens if a thrust reverser inadvertently deploys?
FADEC limits respective engine thrust to idle
What engine thrust rating(s) may only be used for 10 minutes.
TO-1
TO-RSV (TL beyond TOGA)
GA (two engine go-around)
GA-RSV (one engine go-around or windshear)
What is FLEX?
Reduced takeoff thrust based on assumed temperature (telling the FADEC that it is warmer than it actually is so it will reduce the thrust)
Can the FLEX thrust be reduced lower than CLB thrust?
No
POWER PLANT
START/STOP Selector Knob
-STOP
Commands FADC to shut down the engine, provided the associated thrust lever is in the IDLE position
POWER PLANT
START/STOP Selector Knob
-RUN
Normal position for engine operation
POWER PLANT
START/STOP Selector Knob
-START
Initiates the engine start sequence
IGNITION Selector Knob
-OFF
Deactivates the ignition system on the ground when dry motoring the engine on the ground there is no fuel flow. The FADEC disregards the OFF position in flight
IGNITION Selector Knob
-AUTO
FADEC automatically controls the ignition system, depending on engine requirements
IGNITION Selector Knob
-OVRD
Directs FADEC to continuously activate both igniters
N1 Spool
Fan (Single-stage, low pressure), driven by 4-stage low pressure turbine.
N2 spool
10-stage, axial flow compressor driven by 2-stage high pressure turbine.
