Engine Questions

Question 1

What types of engines are on the aircraft?

Answer 1

• Two General Electric CF-34-8E5
• Hi-bypass, 2-spool, axial-flow, turbo-fan

Question 2

How much thrust do the CF-34-8E5 engines produce?

Answer 2

• 13,000-14,200 lbs. (ISA)

Question 3

Describe N1 spool

Answer 3

• Single-stage fan
• 4-stage LP turbine

Question 4

Describe N2 spool

Answer 4

• 10-stage compressor (gas generator)
• 2-stage HP turbine

Question 5

How many igniters per engine?

Answer 5

• 2 per engine

Question 6

How many igniters activate for engine start?

Answer 6

• Ground 1 igniter ( switch in AUTO )
• Flight 2 igniters ( switch in AUTO )

Question 7

What happens when the ignition switch is selected to OVRD?

Answer 7

• Activates both igniters on the ground or in flight

Question 8

Can the igniters be turned off during flight?

Answer 8

• 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

Question 9

What controls the engine?

Answer 9

• A two-channel FADEC
• One channel is active and the other channel remains in standby as a backup

Question 10

Is only one FADEC channel used every flight?

Answer 10

• No. They automatically alternate with each engine start

Question 11

What does the cyan line on the N1 gauge represent during approach? When does it appear?

Answer 11

• The minimum N1 for bleed requirements in icing conditions
• Configured for landing < 1200’ RA (when anti-ice is ‘ON’)

Question 12

What sources are available for engine starting?

Answer 12

• APU
• Ground source (huffer cart or air bottle)
• Opposite engine (crossbleed start)
• Windmill start

Question 13

Does the FADEC provide engine start protection?

Answer 13

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

Question 14

What will the FADEC automatically do in case of a start on the ground?

Answer 14

• FADEC will not allow FF if ITT >120°C
• FADEC will automatically dry motor engine and introduce fuel when ITT <120°C

Question 15

Describe the engine start sequence

Answer 15

• 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

Question 16

Engine stabilizes:

Answer 16

• N1 27%
• ITT 460°C
• N2 62%
• FF 550 lbs/hr
• Oil Pressure >25 psi

Question 17

What does WML mean on the engine indications?

Answer 17

• Windmilling engine
• The FADEC has detected a flame-out and is attempting an auto re-light, or
• An assisted start has been commanded

Question 18

What provides underspeed and overspeed protection?

Answer 18

• The FADEC via the FMU
• Approximately 52% N2 and 102% N2 respectively

Question 19

What happens after 3 overspeed detection events?

Answer 19

• FADEC will not re-light the engine

Question 20

What heats the fuel and cools the engine oil?

Answer 20

• Fuel/Oil heat exchanger

Question 21

What is ATTCS? What controls it?

Answer 21

• Automatic Take-off Thrust Control System
• Provides max thrust reserve (RSV) according to current rate previously selected via the MCDU
• FADEC controlled

Question 22

What will trigger an ATTCS event?

Answer 22

• N1 difference >15% between engines
• Engine failure during TOGA
• Windshear detected

Question 23

When is thrust reverse available?

Answer 23

• Weight-on-wheels (ground use only)

Question 24

What happens if a thrust reverser inadvertently deploys?

Answer 24

• FADEC limits respective engine thrust to IDLE

Question 25

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

Answer 25

• TO-1
• TO-1 RSV (TL beyond TOGA)
• GA (two-engine go-around)
• GA-RSV (one-engine go-around or windshear)

Question 26

What is FLEX?

Answer 26

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

Question 27

Can the FLEX thrust be reduced lower than CLB thrust?

Answer 27

• No