Engine Flashcards
What type of engines are one the aircraft?
2 General Electric hi-bypass, 2-spool, axial-flow, turbofans
Describe N1 spool
- Single stage fan
- 4 stage LP turbine
Describe the 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 engines?
- A two-channel FADEC
- One channel is active and the other channel remains in standby as a backup
Is only one FADEC channel used ever 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 < 1200’ RA (when anti-ice is ON)
What sources are available for engine starting?
- APU
- Ground source (suffer cart or air bottle)
- Opposite engine
- Windmill start
Does the FADEC provide engine start protection?
Only on the ground for a hot start, hung start or no light-off
What will the FADEC automatically do in case of a hot start?
- FADEC will not allow FF if ITT > 120C
- FADEC will automatically dry motor engine and introduce fuel when ITT < 120C
Describe the engine start sequence
Start switch to START:
- 7% N2: Ignition
- 20% N2: Fuel flow
- 20% N2 + 5 secs: Light-off
- 50% N2: Ignition off
Describe engine indications after it stabilizes following engine start
- N1: 27%
- ITT: 460C
- N2: 62%
- FF: 550 Lbs/hr
- Oil pressure: > 25psi
What does WML mean on the engine indications?
- Windmilling engine
- The FADEC gas detected a flameout and is attempting an auto relight, or
- An assisted start has been commanded
What provides under- and over-speed protection?
- The FADEC via the FMU
- Approximately 52% N2 and 102% N2 respectively
What heads the fuel and cools the engine oil?
Fuel-oil heat exchanger
What is ATTCS? What controls it?
- Automatic takeoff 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 difference >15% between engines
- Engine failure during TOGA
- Windshear detected
When is thrust reverse available?
Weight on wheels
What happens if a thrust reverser inadvertently deploys
FADEC limits respective engine thrust to IDLE
What engine thrust ratings may only be used for 5 minutes?
- TO1
- TO-RSV (TL beyond TOGA)
- GA (two-engine go-around)
- GA-RSV (one-engine go around or wind shear)
What is FLEX?
Reduced thrust takeoff based on assumed temperature (telling FADEC its warmer than it actually is so it will reduce the thrust)
Can the FLEX thrust be reduced lower than CLB thrust?
No