CRJ 200 - Powerplant

Question 0

Describe the design of the CF34 engine.

Answer 0

Dual rotor free turbine engine. N1 fan driven by 4 low pressure turbines (LPTs). N2 compressor with 14 stages driven by 2 high pressure turbines (HPTs).

Question 1

What is the rated thrust of the CF34-3B1 engine? With APR?

Answer 1

8729lbs, 9220lbs with APR.

Question 2

What PSI is required for a crossbleed start?

Answer 2

60psi.

Question 3

How many igniters does the engine have? What are their power sources?

Answer 3

Two igniters (A and B) per engine. Ignition A uses AC ESS (A=AC) and ignition B uses DC BATT through a static inverter (B=Battery). They both require AC power, but from different sources (A=AC and B=Battery + inverter).

Question 4

How many valves open when the ENG START switchlight is pressed in?

Answer 4

4. L and R 10th stage bleed valves, ISOL valve and ATS valve.

Question 5

Pressing the ENG STOP switchlight does what?

Answer 5

Closes the ATS valve and disengages the starter. Stops ignition.

Question 6

What items are driven by the N2 accessory drive?

Answer 6

IDG, engine driven fuel pump, oil pump, hydraulic pump, alternator for the ECU and air/oil separator. Start motor is also connected to the accessory drive via a sprague clutch when starting the engine.

Question 7

What does the L or R ENG START message indicate?

Answer 7

Associated ATS valve is open.

Question 8

How many horsepower is the Air Turbine Starter (ATS)?

Answer 8

62HP.

Question 9

When does the engine starter cut out?

Answer 9

55% N2. Ignition too.

Question 10

How are the ignition systems powered?

Answer 10

Ignition A is powered by AC ESS, and Ignition B is powered by a static inverter connected to the DC BATT bus. Essentially both are AC powered, but via different sources.

Question 11

At low power settings what type of speed control is in effect? High power settings?

Answer 11

N2 (hydromechanical) for low power, N1 (electric fan control) for high power (N1 > 79%) provided engine speed switches are on and the system is operational.

Question 12

What happens to the N2 indicator when wing anti-ice is on?

Answer 12

Amber arc from 0-78% N2.

Question 13

A failure of the high pressure engine driven fuel pump will result in what?

Answer 13

Engine failure.

Question 14

What is 7th stage bleed air used for? 10th? 14th?

Answer 14

7th for oil seal pressurization and sump pump venting. 10th for engine starting, pressurization and air-conditioning, and avionics cooling. 14th for anti-ice and thrust reverse system.

Question 15

What is APR? When is it armed? When is it activated? What does it do?

Answer 15

Automatic performance reserve armed for 5 minutes when-

1. APR switches set to ARM
2. Both engine speed switches ON
3. Both N1 > 79%
4. Weight On Wheels
5. At least 2 DCUs and each engine’s ECU operating. Activated when an engine’s N1 < 67.6%. APR will send an increase in N1 to both engines, but since the inoperative engine is off N1 speed control (N1 < 79%) and is on N2 speed control, it does not receive the signal. APR also changes color logic associated with ITT limitations in accordance with transient temperatures. However, it does not prevent limitations from being exceeded.

Question 16

What are the N1 bugs’ colors and shape?

Answer 16

Takeoff N1 is a cyan carrot, reduced is magenta. Cruise N1 is a cyan doughnut.

Question 17

How many fuel nozzles are there for each engine?

Answer 17

18 injector nozzles with dual orifices.

Question 18

How does N2 vibration indications get displayed?

Answer 18

If N2 vibrations exceed 1.7mils a VIB icon appears on the N2 gauge.

Question 19

What indication will be given if the APR fails?

Answer 19

APR INOP caution

Question 20

What are the “bare essentials” for an engine start?

Answer 20

28vDC and 40 psi.

Question 21

What cools the engine oil?

Answer 21

Heat exchanger with fuel.

Question 22

During climbout your lunch box falls and turns off the engine speed switches. What can you expect, and what do you do?

Answer 22

You can expect a rapid acceleration in engine speed, and you need to reduce thrust.

Question 23

If N2 speed control is used for takeoff is APR thrust available?

Answer 23

No. APR relies on N1 speed control.

Question 24

If ignition is left armed during a subsequent engine failure will the ignition automatically come on?

Answer 24

No. Ignition automatically comes on only during stall protection.

Question 25

What is necessary for thrust reverse to operate?

Answer 25

14th stage bleeds open. Switches armed. Idle thrust. WonW or wheel speed > 16 knots.

Question 26

When do we use CONT IGNITION?

Answer 26

Takeoffs and landings on contaminated runways, takeoff with crosswind > 10 knots, flight through moderate or heavier intensity rain and turbulence and flight in the vicinity of thunderstorms.

Question 27

During start on a cold day

Answer 27

what N1 is necessary before fuel is introduced?,Verified rotation (no specific value).

Question 28

What does an amber REV on the N1 gauge mean? Green?

Answer 28

Amber means the translating cowl is unlocked. Green means deployed.

Question 29

What does the EMER STOW switchlight do? What will EICAS display?

Answer 29

Electric emergency stow system will directs 14th stage bleed air to the PDU to stow the unlocked reverser. Switchlight will illuminate and EICAS will display L/R REV UNLK.

Question 30

What do you check during the start sequence?

Answer 30

ITT < 120°, N2 ≥ 20%, oil pressure > 0, N1 rotation during cold weather ops, fuel flow, lightoff, starter cutout at 55% N2, stabilized N1 at 22-25%, N2 at 62.9-64.0%, fuel flow at 200-400lbs, and oil pressure.

Question 31

What are some of the systems that are armed/checked when N1 > 79%?

Answer 31

Pressurization, GLDs, APR, EICAS message inhibit.

Question 32

How do you do the FFOD fuel feed check valve test? Why are we checking this?

Answer 32

Fuel pumps are turned off to ensure the operating engine's motive flow will not feed fuel to the inoperative engine. Accomplished on FFOD during engine start (R FUEL LO PRESS) and engine shutdown (L FUEL LO PRESS). R FUEL LO PRESS when left engine is operating, fuel pumps off, and the check valve at the left engine's main ejector is suppressing fuel to the right engine.

Question 33

What do you do if you don't get the R/L FUEL LO PRESS right away?

Answer 33

Officially you can wait up to 2 minutes. Dry-motoring for 30 seconds is also recommended.

Question 34

Would you use the APU to try an engine restart in flight?

Answer 34

No. Thrust on the operating engine would produce a higher pressure in the manifold than the APU can produce thus preventing APU bleed air from being used for the start. Trying to close the operating engine's 10th bleed SOV would not work since the valve opens during engine start. An inflight crossbleed start would be better (procedure includes closing APU LCV).

Question 35

What does NO STRTR CUTOUT mean?

Answer 35

Air Turbine Starter valve did not close.

Question 36

Without checking the N2 gauges how could you tell if they were NOT within 2% of each other?

Answer 36

Oil pressure gauges would still appear instead of being replaced with VIB gauges. AC ELEC page would show a white engine instead of cyan and a white IDG instead of green.

Question 37

When the thrust levers are placed in shutoff specifically how does the engine stop getting fuel?

Answer 37

FCU

Question 38

Which valves fail open? Closed? Why?

Answer 38

Open- L/R 14th stage SOV and cowl anti-ice valves | Closed- L/R 10th stage SOV, APU LCV, 10th ISOL, 14th ISOL and wing anti-ice valves