Engines System Flashcards
Is TO-1 the highest thrust for takeoff?
No, TO is. TO-1 is a 5% derate
Is CLB-1 the highest thrust climb setting?
No, CLB is. CLB-1 is a derate.
What is “reference” thrust referencing?
Whatever is on top of the EICAS N1 indications. So things like “D-TO 1” or “CLB-2” etc.
What does an amber REV tell you? Green?
Amber- reverse thrust in transit. Green- reverser fully deployed.
On the N1, what is the amber line?
Max N1
On the N1, what is a red line?
N1 RPM operating limit (overspeed over this line)
On the N1, what is a green line?
Reference N1
On the N1, what is a magenta line?
Reference N1, but commanded by the FMC
On the N1, what is a white line?
Commanded N1 by thrust lever position. (It would jump up if you pushed the power up, and the white solid bar would catch up to that line)
What is the white solid bar in an N1 tape?
Actual N1 RPM
NOTE: Turns red if operating limit reached.
On the EGT, what does the red line mean?
EGT limit (top of gage)
If a lower red line exists, it’s for engine start limit
On the EGT, what does the amber line mean?
Continuous EGT limit
The EGT tape itself can be white, amber, or red. What does each mean?
White: Normal range
Amber: Continuous operating limit
Red: Start or takeoff limit reached
During takeoff or go around, the continuous EGT may be exceeded, but the indication will show white. (So you don’t reject or freakout on a go around.) How long is red inhibited for? And will it go red if the maximum limit is reached?
It inhibits continuous limit indication from displaying amber for 5 minutes after the TOGA switch pressed.
It will still go red if maximum temp is exceeded.
What does the red line mean on the N2 gage?
N2 operating limit
The N2 tape is either white or red. What does each mean?
White: Normal range
Red: Limit exceeded
What does a magenta line mean on an N2 tape?
Fuel on indicator. Minimum N2 to introduce fuel.
When is the only time a magenta line would be displayed on an N2 tape?
When the associated fuel selector is in cutoff.
What is fuel flow measured in? You see 3.3. What does that mean?
Measured in kilograms per hour X 1,000.
3.3 = 3,300 kgs an hour.
On the oil pressure gages, what does a white triangle mean? Red?
White: Normal
Red: operating limit reached
On the oil pressure indicator, what does the amber line mean?
Caution range
What does white, amber and red mean on an oil temperature gage?
White: Normal
Amber: Caution
Red: Operating limit reached
White is normal for oil quantity. What color means low quantity, or oil differential reached?
Magenta
Do engine vibration indications have any color other than white?
No just white
What does selecting a fuel control switch to ON do?
Autostart ON:
-Opens spar fuel valve
-Opens engine fuel valve
-EEC sequences start valve, fuel metering valve, and igniters
Autostart OFF:
-Opens spar fuel valve
-Opens engine fuel valve
-Energizes igniters
What does selecting a fuel control switch to CUTOFF do?
-Closes fuel valves
-Removes igniter power
-Commands hydraulic pumps to operate when demand pump in AUTO
-Unlocks fire switch
What does pulling an engine start switch do when autostart is on?
-Arms start valve
-Opens engine bleed air valve
What does pulling an engine start switch do when autostart is not on?
-Opens start valve
-Opens engine bleed air valve
When does an engine start switch release after it has been pulled?
50% N2
You see an engine start switch is illuminated. Why is it illuminated?
Start valve is open
On the ignition panel, there is a STBY switch with 1, NORM, and 2. What does this switch do? Why would you use this switch?
NORM: AC power system supplies power to selected igniters. Standby system steps in automatically if AC fails. VIA Main STBY Bus
1 OR 2: Standby power system powers selected igniters, regardless of the AUTO selector. So if you selected 1, standby power fires the number 1 igniters. If you selected 2, standby power fires the number 2 igniters.
an example of when you would use this is if the CON switch is broken
On the ignition panel, what does the CON switch do?
Selected igniters operate continuously
Also, command approach idle minimum
On the ignition panel, what does the AUTO switch do? It has 2 positions, SINGLE or BOTH.
SINGLE: The EEC alternates igniter 1 and igniter 2 after each ground start. The EEC also selects both igniters for in-flight start or a flameout.
BOTH: Commands both igniters to fire for both ground or in flight starts
What does the AUTOSTART switch do?
ON: Arms the autostart system
OFF: Autostart disabled, start manually controlled
On the ELEC ENG CONTROL panel, there are 4 different EEC switches. Each has 2 positions, NORM (white) and ALTN (amber). What do each of these switches do?
NORM: EEC in normal mode
ALTN: EEC in alternate mode
On the overhead MX panel, there are 4 switches called EEC MAINT switches. NORM or TEST modes. What do they do?
NORM: Supplies power for normal EEC operation
TEST: Powers the EEC for MX testing when engines are not powered.
Generally, what type of engines do we have?
Dual rotor, axial flow, high bypass turbofans.
What drives the accessory gear box?
N2 rotor
How many EECs?
4,
1 per engine
What controlling parameter does the EEC use as its basis for setting power? Does it matter if it’s in normal or alternate mode?
N1 is the controlling parameter for setting thrust.
It is N1 always, mode does not matter.
What powers each EEC?
An alternator in each accessory gearbox.
How does the EEC increase or decrease N1?
It modulates the fuel metering unit to add or reduce fuel. More fuel = more power
What is the difference between EEC normal mode and alternate mode?
Normal:
-Keeps thrust constant regardless of temperature or bleed air demands
-Thrust levers will not move if bleed demands change, allowing for fixed position
-Thrust limit protection Maximum N1 is full throttle (overboost protection)
Alternate:
-Thrust must be adjusted for changes in bleed demands
-No Thrust Limit Protection (overboost protection)
Can you run the autothrottle with EECs in alternate?
Yes, but all 4 must be in alternate mode. If you had 1 EEC fault and it went into alternate mode, you need to put all 4 into alternate to get auto throttle
When does an EEC automatically switch from normal to alternate mode?
If the EEC detects a fault
What are the 2 idle settings?
Minimum idle
Approach idle
What are the differences between minimum idle and approach idle? When are they selected?
Minimum idle: lower idle setting (longer spool up). This is the normal setting by the EEC. After landing, it goes back into minimum idle 5 seconds after touchdown.
Approach idle: Higher idle setting (less spool up) Approach idle selected in flight when
-Nacelle anti-ice is ON
-Flaps are in a landing position
-Continuous ignition switch ON
What is EEC overspeed protection?
EEC monitors N1 and N2 and will reduce fuel to the engine despite thrust lever position to prevent the rotor from exceeding the operating limit.
How does the autostart system protect against hot, hung, and no EGT starts on the ground?
Hot and hung starts: EEC cuts off fuel and ignition, reschedules fuel, tries again. It makes 3 attempts then motors for 30 seconds before closing the start and bleed air valves.
No EGT rise. EEC cuts off fuel and ignition, motors for 30 seconds, tries this 3 times. After the final attempt, it motors for 30 seconds and then closes the start and bleed air valves.
Do in flight autostarts have any auto abort features?
Yes… and no.
It reacts to hot start (based on takeoff limit) and hung starts. It cuts off fuel, but will just try again and again until a successful start or fuel selector is put to CUTOFF.
Explain how in flight auto-relight works.
If N2 rapidly decreases, or its below idle RPM, both igniters activate.
If it restarts, the engine stabilizes at idle first, then brings the power back up to the thrust lever position.
What warms the fuel up before it enters the engine?
The fuel/oil heat exchanger.
What supplies fuel to the engines?
Fuel pumps in the main tanks
Where is fuel flow measured from?
Downstream of the engine fuel valve
How is oil pressurized?
Engine oil pump.
How are the revers thrusters actuated?
Bleed air from the respective engine
On the engine vibrations, you will see either FAN, LPT, N2, or BB. What is BB?
Broadband. Means it can’t determine where the vibrations are so its average engine vibrations.
Are there engine driven fuel pumps? How many? What powers them?
Yes, they are considered “boost pumps” because they do not supply the engine with fuel, but rather boost the pressure before it enters the engines.
There are 2 engine fuel pumps per engine. First stage and second stage. Powered by the N2 rotor.
Describe the flow of fuel once it leaves the main wing tank pump.
1.) Fuel spar valve
2.) First stage engine pump
3.) Second stage engine pump
4.) Fuel/Oil heat exchanger
5.) Fuel filter
6.) Fuel metering unit
7.) Engine fuel valve
When do the selected igniters automatically activate for an INDIVIDUAL engine?
-During start when N2 RPM is less than 50%
-Nacelle anti-ice ON
-Engine flameout (Both Igniters operate)
“Selected” is referring to the selector position of the Auto Ignition sector on the engine start panel (Single or Both)
What conditions would cause selected igniters to simultaneously for ALL engines to activate?
-The trailing edge flaps are out of the up position
-The Continuous Ignition switch is ON.
“Selected” is referring to the selector position of the Auto Ignition sector on the engine start panel (Single or Both)
What conditions require CON ignition?
· Heavy rain
· Severe turbulence
· Volcanic ash
· Icing conditions
· Standing water or slush on runway
What type of engines does 409MC have?
General Electric
CF6-80C2-B1F
When you press the ENG Bleed air switch into the closed position you close three valves. what are they?
Engine bleed valve
PRV
HP
