Engine Questions Flashcards
What type of engines are on the aircraft?
- Two 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?
- A two-channel FADEC
- One channel is active and the other channel remains 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 requirement 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 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 start on the ground?
- 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 momentarily to start
- 7% N2 ignition
- 20% N2 fuel flow
- 20%N2 + 5 sec Light off
- 50% N2 ignition off
- 50% N2 starter cutout
Engine stabilizes?
- N1 27%
- ITT 460c
- N2 62%
- FF 550lbs/hr
- Oil Pressure >25psi
What does WML mean on the engine indications?
- Windmilling engine
- The 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 the FMU
- Approximately 52% N2 and 102% N2 respectively
What happens after 3 overspeed detection events?
- FADEC will not relight the engine
What heats 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 engine
- Engine failure during TOGA
- Windshear detected
When is thrust reverse available?
Weight-on-wheels (ground use only)
What happens if a thrust reverser inadvertently deploys?
- FADEC limits respective engine thrust to IDLE