Engines

Question 1

Which two engine indications are displayed full time on the EICAS?

Answer 1

N1 and EGT

Question 2

State the sequence of events that occur when you pull a start switch with the AUTOSTART Switch ON.

Answer 2

• arms start valve
• opens engine bleed air valve

Question 3

State the sequence of events that occur when you pull a start switch with the AUTOSTART Switch OFF.

Answer 3

• opens start valve 

  *opens engine bleed air valve

Question 4

Which valves close at 50% N2 RPM during engine start?

Answer 4

• start valve closes
  
- engine bleed air valve closes

Question 5

What is the function of the AUTO Ignition Selector in the SINGLE position?

Answer 5

• EEC alternates igniter 1 and igniter 2 for each ground start
• EEC selects both igniters for in-flight start or flameout

Selected igniters operate for specific engines when any of the following occur:
• during start when N2 RPM less than 50%
• nacelle anti-ice ON
• engine flameout
Selected igniters operate for ALL engines any of:
- trailing edge flaps out of up position
- CONT IGNITION ON

Question 6

What is the function of Standby (STBY) IGNITION selector in NORM?

Answer 6

• AC power system supplies power to selected igniters
  
* standby power system supplies power continuously to all igniters if AC power system is not powered

Question 7

What happens when Continuous (CON) IGNITION switch is ON?

Answer 7

• selected igniters operate continuously
• commands approach idle minimum

Question 8

When is ignition selected for each engine individual?

Answer 8

• during start when N2 RPM less than 50%
• nacelle anti-ice ON
• engine flameout

Question 9

When is ignition selected for all engines?

Answer 9

• trailing edge flaps out of up position
• CONT IGNITION ON

Question 10

What color does the EGT change to if the EGT start limit is exceeded?

Answer 10

Red

Question 11

What does X-BLD mean when displayed next to the N1 indication when an engine is shut down?

Answer 11

• Cross bleed air recommended for in-flight start
• in-flight start envelope displayed, and
• airspeed lower than required for windmilling start

Question 12

How many igniters are selected for ground start, and how many for inflight start?

Answer 12

1 for ground start (unless BOTH selected)
2 for in-flight start

Question 13

Describe the engine start sequence with the AUTOSTART Switch is ON.

Answer 13

Engine Start Switch pulled
- arms start valve
- opens engine bleed air valve

Fuel Control Switch to RUN - initiates auto start sequence (3)
* opens spar fuel valve
* opens engine fuel valve
* EEC sequences start valve, fuel metering valve, and igniter operation 

- EEC opens start valve (start switch light illuminates)
- At predetermined N2 EEC introduces fuel and ignition (one on ground, 2 in flight)
- Starter cutout at 50% N2 (start switch light extinguishes)
- EEC monitors EGT and N2 until engine stabilizes at idle and red bar removed from EGT indicator
- Verify N1 rotation and oil pressure indication by idle N2 (62-67)% - not monitored by EEC
- observe APU increase pneumatic pressure for engine starting

Question 14

During an engine start, the autostart system can abort the start for which three malfunctions?

Answer 14

Hot start
Hung start
No EGT rise

Question 15

Which two parameters does the autostart system not monitor?

Answer 15

N1
Oil pressure

Question 16

How does the EEC protect against an impending hot/hung start?

Answer 16

before starter cutout:
- EEC cuts off fuel, adjusts the fuel schedule, then reapplies fuel for another attempt.
- The EEC makes three attempts before aborting the autostart sequence.
- Fuel and ignition are cut off.
- The engine motors for 30 seconds before the start and bleed air valves close.



after starter cutout:
- If the EEC detects an impending hot start or a hung start after starter cutout, the autostart sequence is aborted immediately. The engine does not motor.

Question 17

How does the EEC protect against no EGT rise?

Answer 17

• cuts off fuel and ignition.
• The engine motors for 30 seconds.
• The EEC applies fuel and ignition to both igniters for another attempt.
• The EEC makes three attempts before aborting the autostart sequence.
• The engine motors for 30 seconds before the start and bleed air valves close.

Question 18

At what EGT limit does the EEC abort an inflight start through the autostart system?

Answer 18

If EGT reaches takeoff limit or hung start, cuts off then reapplies fuel. (allows EGT to go past start limit to reach takeoff limit)
Autostart NOT automatically aborted for inflight start

Question 19

How is the engine cooled?

Answer 19

Oil via the fuel/oil heat exchanger

Question 20

How is the engine thrust reverser actuated?

Answer 20

Pneumatically - engine bleed air, reverses fan flow

Question 21

What protects the thrust reversers from deploying inadvertently in flight?

Answer 21

Interlock stops it being deployed when thrust levers in forward.
If deployed inadvertently system auto applies bleed air to stow and lock reverser

Question 22

What is broadband vibration in the airborne vibration monitoring system, and how is it displayed?

Answer 22

average vibration level for whole engine - displays as BB