Chapter 7 - Engines, APU Flashcards
What engines are on the Kalitta 747-400’s?
CF6-80C2-B1F (BCF/F)
CF6-80C2-B5F (ERF)
How much thrust do the engines produce?
57,900lbs (BCF/F)
62,100lbs (ERF)
What controls the engines?
Electronic Engine Control ( EEC ) Just like FADEC, the EEC’s has full authority over engine operation.
How many channels does each EEC have?
Each EEC has 2 channels. Normal & Alternate
What happenes if both EEC’s fail?
The engine will flame out!
Describe EEC Idle Selection.
EEC selects min idle or approach idle
Min idle is lower than approach idle
Approach idle is selected inflight when -
- NAI is on
- Flaps in landing position
- Continuous ignition is on
Approach idle is maintained until 5 secs after touchdown
Approach idle is selected during reverse thrust
Describe EEC Overspeed Protection.
Thrust settings above idle the EEC monitors N1 and N2 to prevent overspeed.
If the rotor speed approaches overspeed then the EEC commands the fuel metering unit to reduce fuel flow.
What do we have to monitor during Autostart?
What does EEC monitor and abort for on Autostart?
We must monitor
- Oil Pressure
- N1
- Fire
Call out “Oil Pressure and N1”
EEC Monitors
- EGT
- N2
What will Autostart abort for?
Hot Start
Hung Start
No EGT
Describe the Autostart sequence
Pull out the start switch
- Arms start valve
- Opens engine bleed valve
Move fuel control switch to RUN - Initiates autostart sequence
- EEC opens start valve
- Start light illuminates
- At specific N2 EEC opens fuel valve
- EEC energizes ignitor (1 on gnd/2 inflight)
- Starter cuts out at 50% N2
Start switch releases automatically
- Start and engine bleed air valve closes
- Start light goes out
- ignition discontinues
Describe Autostart No Light Off
Abort start
Motors for 30 seconds
Turns on both igniters
Reattempt start
3 total tries then motors and shuts down
Describe Autostart Hot/Hung Start
Aborts start
Motors for 30 seconds
Adjusts fuel metering
Reattempt start
3 total, then motors and shuts down
Ignition Control

Each ignition has 2 ignitors
Ignitor 1 is powered by AC bus 1
Ignitor 2 is powered by AC bus 3
Standby is powered by the Main Standby bus with the main battery as a backup
When does Auto Ignition operate?

NAI is on
Flaps are out of up
N2 RPM is below 50% during start
Flameout is detected
EEC switches to ALTN, what do you lose?
Autothrottles
Overboost protection
Can you restore autothrottles once one EEC goes to ALTN mode?
Yes, all switches must be put to ALTN mode.
Run QRH, unaffected engines one at a time, retard thrust lever to mid range,
then switch from NORM to ALTN
Can we be dispatched with an EEC with Normal mode INOP?
Yes, all switches to ALTN
If EEC auto transfers to ALTN mode does the thrust change?
No, thrust only increases when ALTN is manually selected.
What happens if the Thrust Reverser accidently deploys inflight?
Bleed air from the respective engine is used to stow the thrust reverser.
When does the EEC swap igniters automatically?
After every 2 engine starts.
During engine start what is the max EGT?
870ºC
Red Limit
At what N2 RPM will starter cutout occur?
Starter cutout occurs at 50% N2 RPM
What is the min oil pressure you should see when the engine is at idle?
10 PSI
Under what conditions would continuous ignition come on automatically?
On ground
NAI is on
Inflight
NAI is on
Flaps out of up
N2 below 50%
What is max EGT on Takeoff?
960ºC
5 minutes only
What is max continuous EGT?
925ºC
When will standby ignition activate with the switch in NORM?
Loss of AC power
What engine protection, if any, is lost with an EEC in Alternate Mode?
Overboost protection
What is the minimum oil quantity for dispatch?
16 Quarts
When will the engine oil quantity appear magenta when the oil quantity is in the normal range?
When the oil quantity increases by a pre determined amount (6 quarts) because a leaking fuel/oil heat exchanger.
The amber line on the N1 indicator represents what?
The maximum thrust N1
With autostart functioning normally, under what conditions must the start be manually aborted?
• No N1 indication by idle N2
• No oil pressure rise
• Fire
When will the EICAS Memo Message APU RUNNING be displayed?
When the APU Selector is ON and the APU N1 exceeds 95%
What happens when the APU is selected off?
• Closes the APU bleed air valve
• Does a 1 minute cool down cycle, then shuts off
• Closes the APU inlet door
When does the EEC command approach idle?
• Nacelle anti-ice selected on
• Flaps in the landing position
• Continuous ignition selected on
On takeoff, after 80 knots the EGT goes to 950. Would the EGT tape or digital readout change color? Would you reject?
• No, not until 5 minutes after TOGA is pushed
• No
What conditions require CONTINUOUS IGNITION (IGNITION CON) in the ON position?
- Heavy rain and hail
- Severe turbulence
- Volcanic ash
- Icing conditions
- Standing water or slush on runway
MAX Starting EGT (unlimited)?
750 C
Starting Max transient EGT?
870 C
Maximum continous oil temperature?
160 C
Maximum transient Oil temperature?
175 C
Decribe the NI Rotor?
Four Stage Compressor driven by a Four Stage Low Pressure Turbine
Describe the N2 Rotor?
A 14 Stage Compressor driven by a Two Stage High Temperature turbine
What are the two primary engine indications on EICAS?
N1
EGT
Maximum N2 Limit
112.5%
Maximum N1 Limit
117.5%
What does the Fuel Control Switches in RUN do (Autostart switch on)?
- opens spar fuel valve
- EEC sequences start valve, fuel metering valve, and igniter operation
What does the Fuel Control Switches in the RUN position (Autostart switch OFF) do?
- opens the spar fuel valve
- opens engine fuel valve
- energizes igniter(s)
What happens when you put the Fuel Control Switches to CUTOFF?
- closes fuel valves
- removes igniter power
- commands related hydraulic demand pump to operate when Demand Pump selector in AUTO
- unlocks Engine Fire switch
What is the function of the Standby (STBY) IGNITION selector in NORM?
AC power system supplies power to selected igniters
Standby power system supplies power continuously to all igniters if AC power system is not powered.
1 or 2 - standby power system supplies power continuously to the related igniter regardless of Auto ignition selector or EEC
What happens when you turn the Continuous IGNITION (IGNITION CON) Switch ON?
- Selected igniters operate continuously
- Commands approach idle minimum
What are the start sources for the APU, and which one do we normally use?
TR (Transformer‐Rectifier Unit), when Utility Bus 4 is powered.
APU Battery, when Utility Bus 4 is unpowered.
TR is the normal switch position.
Can the APU be operated in flight?
Yes, when left running for takeoff it can be operated in flight up to 20,000 feet
Is electrical power available from the APU in flight? How about APU bleed air in flight?
- No, APU electrical power is not available in flight
- Yes, APU bleed air is available in flight for one pack up to 15,000 feet
What APU components are powered by the APU battery?
Inlet door
APU controller
DC fuel pump
APU fire detection system
What APU components are powered by the main battery?
APU fire extinguisher
APU fuel valve
Standby power for the APU controller
What powers the APU starter during a battery start sequence?
The APU battery
(All other APU components are powered by the main battery while the APU starter is engaged)
How long should you wait before turning the battery switch OFF after the APU selector is rotated to OFF, and why?
- 2 minutes
- Allows a complete shutdown sequence, with fire detection capability.
What would cause the APU to shut down automatically?
A limit is exceeded
A fire is detected
Battery switch turned off during APU shutdown sequence.
What does the ON position of the APU switch do?
- opens APU fuel valve and inlet door
- arms APU bleed air isolation valve
- activates DC or two AC fuel pumps
What does the OFF position of the APU switch do?
- closes APU bleed air isolation valve
- initiates normal shutdown
- resets auto shutdown fault logic excetp when shutdown due to APU bleed duct leak
What does the START position of the APU switch do?
initiates automatic start sequence
APU Duty Cycle, time between starts?
- 1 min
- 5 min
- 1 min
- 20 min
- 1 min