GE CF-34-8E5 Engine System Flashcards by DIFS RIPP

(B) What types of engines are on the aircraft?

Two General Electric CF-34-8E5
Hi-Bypass
2-Spool
Axial-Flow
Turbo-fan

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(B) How much thrust do engines produce?

13,800 - 14,200 lbs. (ISA)

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(B) Describe N1 spool?

Single-stage fan

4-stage LP turbine

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(B) Describe N2 spool?

10-Stage Compressor driven by a 2-Stage HP Turbine

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(B) How many igniters per engine?

2 per engine

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(B) How many igniters activate for engine start?

Ground - 1 igniter (AUTO)

Flight - 2 igniters (AUTO)

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(B) What happens when the ignition switch is selected to OVRD?

Actives both igniters on the ground or in flight

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(B) Can the igniters be turned OFF during flight?

In-Flight - Switch may be moved to OFF but FADEC disregards command
OFF position is used for dry motoring on the ground only

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(B) What controls the engine?

Full Authority Digital Electronic Control (FADEC - 2 Channels)
One channel is active and the other channel remain in standby as a back-up

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(B) Is only one FADEC channel used every flight?

No. They automatically alternate with each engine start

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(B) 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 less than 1200’ RA (when A/I is ON)

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(B) What sources are available for engine starting?

APU
Ground Source (Huffer cart or air bottle)
Opposite engine
Windmill

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(B) Does the FADEC provide engine start protection?

Only on the ground for a hot start, hung start or no light-off

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(B) What will FADEC automatically do incase of a start on the ground?

FADEC will not allow FF if ITT greater than 120°C

- FADEC will automatically dry motor engine and introduce fuel when ITT less than 120°C

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(B) Describe the normal engine start sequence?

1 - Start Switch ON then to Run
2 - 7% N2 - Ignition A ON ( FADEC will automatically turn on other ignitor if not light-off or 15 seconds after fuel flow)
3 - 20% N2 - Fuel Flow
4 - 20% N2 + 5 Seconds - Light-OFF!
5 - 50% N2 - Ignition A (B) OFF

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(B) When do you know if the engine is stabilized?

N1 - 27% (2)
ITT - 460°C (4)
N2 - 62% (6)
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_
FF - 550lbs/hr
Oil Pressure - > 25 PSI

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(B) What does VML mean on the engine indications?

Windmilling engine
The FADEC has detected a flame out and is attempting an auto-relight
An assisted start has been commanded

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(B) What provides underspeed and overspeed protection?

1 - The FADEC via the FMU

2 - Approximately 52% N2 and 102% respectively

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(B) What happens after 3 overspeed detection events?

FADEC will not re-light the engine

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(B) What heats the fuel and cools the engine oil?

Fuel/Oil heat exchanger

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(B) 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

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(B) What will trigger an ATTCS event?

1 - N1 difference > 15% between engines
2 - Engine failure during TOGA
3 - Windshear detected

(B) When is thrust reverser available?

Ground only (Weight-on-Wheels WoW)

(B) What happens if a thrust reserver inadvertently deploys?

FADEC limits respective engine thrust to IDLE

(B) What engine thrust rating(s) may only be used for 10 minutes?

1- TO-1 2- TO-RSV (TL beyond TOGA) 3- GA (Two-engine go-around) 4- GA-RSV (One-engine go-around or windshear)

(B) What is FLEX?

Reduced takeoff thrust based on assumed temperature (Basically telling the FADEC that it is warmer than it actually is so it will reduce the thrust)

(I) Why do we FLEX?

To conserve and prolong the life of the engine

(B) Can the FLEX thrust be reduced lower than CLB thrust?

(T) Describe the engine fuel control system

1. FADEC - Full Authority Digital Electronic Control 2. FMU - Fuel Metering Unit 3. PMA - Permanent Magnet Alternator 4. Engine Sensors 5. VGA - Variable Geometry Actuator 6. OBV - Operability Bleed Valve

(T) What does the FMU do?

- Controlled by FADEC - It meters and distributes the proper amount of fuel to the injectors under all conditions - Controls the fuel SOV in normal conditions - Provides overspeed protection

(T) What does a PMA do?

Provides independent source of power to each engine's FADEC (28VDC) for start and back-up at approx. 50% N2

(I) How many fuel injectors does this aircraft have?

18 Fuel Injectors per engine

(I) What does the engine system lubricate on this engine?

AGB - Accesory Gear Box bearings | 5-Turbine Main Shaft Bearing

(T) How many oil pumps?

1 main pump | 4 scavenge pumping elements

(I) What's inside the ACG (not mounted on)?

AGB contains: 1. Oil reservoir 2. Oil Pumps 3. Filter 4. Bypass valve 5. Fuel-heat exchanger

(I) What is mounted on the AGB?

1. Fuel pumps 2. IDG 3. Starter (ATS - Air Turbine Starter) 4. Hydraulic Pump 5. PMA

(I) What controls the start up components?

``` FADEC controls: Fuel Flow Starter Ignition Aircraft controls: Starter control valve Hydraulic engine driven pump Switches power to ignition exciters ```

(I) What provides bleed air to the starter?

1. APU 2. Ground Source 3. Opposite Engine

(T) When does the Hot Start protection commence?

ITT > 815°C on ground

(T) What kind of Thrust Reverser do we have?

Cascades with Transcowls

(T) What is a VGA and what does that do?

Variable Geometry Actuator and it's purpose is to optimize the position of the compressor stators for N1 for efficiency

(I) How are the thrust reversers powered?

Hydraulically - HYD SYS 1 for Engine 1 - HYD SYS 2 for Engine 2 respectively

(I) What is the highest engine thrust possible?

GA-RSV

(T) What are the IDLE Modes?

Flight Idle Approach Idle Final Approach Idle Ground Idle

(O) When must you stow MAX Thrust?

60 knots

(O) When must you stow Min Thrust?

30 knots

(I) Explain approach idle?

``` Enables rapid acceleration to go-around thrust. Activates: 1 - > 15,000 ft. 2 - Flaps 1 or greater 3 - Landing Gear down It compensates for icing automatically ```

(I) When is Final Approach Idle active?

1. - > 1,200 ft. 2 - Landing Flaps 3 - Landing Gear Down It does not compensate for icing but displays minimum target speed for bleed air

(I) Max Reverse TLA?

.5°

(I) Idle TLA?

22°

(I) When does ATTCS engage the clutches to move the TLA to TOGA?

50°

(O) Can you flex all the time?

No, prohibited on contaminated runways

(I) What is the limitation on FLEX?

Cannot exceed 25% of the full takeoff thrust

(O) Engine Starter Duty Cycle Limits?

``` 1 - 90 sec ON/10 sec OFF 2 - 90 sec ON/10 sec OFF 3 - 90 sec ON/5 min OFF 4 - 90 sec ON/5 min OFF 5 - 90 sec ON/5 min OFF - 120 sec ON in flight - ```