Systems - Engines Flashcards
(Refer to AOMII 2-14-05 pg 3)
How is 9th stage air supplied and when is it over-rode?
With a 1 way check valve that is always open and over-rode by 14th stage air when that valve is open.
How soon after engine shutdown should the oil be checked to ensure quantities are within the accpetable range
5 mins.
Should you abort the start if FF drops to zero shortly after light off?
No, this could be a normal condition.
What are the steps for a crossbleed start
1) X Bleed Valve to AUTO or OPEN
2) Starting Eng Bleed Closed
3) Operating Eng Bleed Open
4) Operating Eng > 80% N2
What is the purpose of the engine bleeds
Power the AC packs and Anti Ice
(Refer to FPMU schematic 2-10-10 pg 3)
What does the FPMU do?
1) Pumps Fuel
2) Meters the Fuel to the 16 fuel nozzles based on where you place the TL.
What happens if the IGN is selected OFF and Engine is ON
disables the “auto re-light”, but the engine will continue to run.
What will the FADECs do if one reaches a critical fault
It will auto transfer the engine to the other FADEC.
What happens when the IGN is ON
Both igniters spark continuously (there is no limit to how long you can have ignitors on).
(Refer to AOMII 2-14-05 pg 3)
Identify 3 times you are guaranteed air from the 14th stage (highest pressure)
1) Low thrust settings
2) Anti- Ice On
3) Cross Bleed Engine Start
At what minimum oil level should you notify MX control of low oil quantity
8 qts (not a write up)
What is the purpose of Compressor Variable Geometry (CVG)
To make sure that the engine is more efficient and reduce the likelyhood of compressor stalls
When is the ignition required to be ON
When using “off ship” start and cold start.
When does the PMA have sufficient rotation to power the igniters?
at 10%
How many igniters does the comustion section have and how are they operated?
2 igniters (1 at 12 O’Clock and one at 6 O’Clock). Each igniter is operated by its own FADEC (A or B).
What is the PMA and what items does it power?
Permanent Magnetic Alternator and is powered by the N2 compressor. Items powered by PMA:
1) Ignition
2) FADECs above 50% N2
3) Backup power source for Thrust Levers & Thrust Rating Buttons.
Does the Flight Crew have any control over which FADEC will fire the inginters during start?
No, the FADEC will alternate this between legs.
What does Resetting a FADEC do? What does selecting ALTN (Alternate) on the FADEC do?
1) Clears any transient faults
2) Manually switches to the other FADEC in flight.
What is meant by FADECs sending discreet signals
The FADEC is running a system other than the engine
(Refer to FPMU schematic 2-10-10 pg 3)
What happens if the FPMU quits
The Engine Will Quit
If you are operating single engine, and need to perform a Go Around and it is hot outside (greater than 19°C), what will the FADEC do?
Turn off the onside packs and direct bleed air to rearward thrust.
If the fuel pumps become inop, to what altitude will the FPMU “suck feed” fuel
Up to 25,000’
What is the maximum time to engage the starter? What is the typical time? What happens if you exceed the maximum limit?
1) 3 seconds
2) 2 seconds
3) It disables the knob unless you reset the FADEC which clears the knob disable.
Why is the ITT start temp limit reletivley low (800°C) compared to the contunuous operation ITT (901°C)
Becuase the temperature sensor probe is inside a stator and therefore shielded from direct heat.
What technique should you use when deploying Thrust Reverersers before all three mains are on the ground
Limit yourself to idle reverse until nose gear is down
What are the reasons to abort Start (on the ground or in flight)
1) Fuel Flow > 800lbs/ hr prior to light up
2) No light up within 10 seconds after FF
3) ITT rises rapidly towards start limit
4) ITT approaches the start limit
5) N2 remains steady or decreases for more than 30 secs
6) Unusual Noise or Vibration
7) Engine Instruments indicate abnormal conditions
8) Visible burning on the exhaust
9) Oil Pressure <34 psi after the start is complete.
(Refer to FPMU schematic 2-10-10 pg 3)
What does the Fuel- Cooled Oil Cooler do (FCOC)
As the fuel flow from the centrifugal pump to the FCOC, the cold fuel is used to cool down the hot oil and in turn the hot oil will warm the fuel (symbiotic relationship).
At what minimum oil qty should you actually write up?
6 qts.
What are the components of of the N1 low pressure section
1) 24 bladed Fan Drive
2) Inner Shaft
3) Low Pressure Turbine
How are each of the TR locks commanded and operated.
1st two sets are electrically commanded and hydraulically operated.
3rd set is electrically commanded and electrically operated.
What does the HP Turbine Drive?
What does the LP Turbine Drive?
HP drives the compressor
LP drives the Fan.
(Refer to AOM II 2-10-15 page 4)
What is the purpose of the scavenge pumps?
To retrieve oil from the items being lubricated.
During end start, when the IGN is in auto, at what % of N2 will it fire and how is this accomplished
14% N2 and both igniters are fired automatically.
(Refer to FPMU schematic 2-10-10 pg 3)
What will happen if the shaft driving both the centrifugal pump and the gear pump breaks?
Both those pumps will go off line.
From where do you obtain the temp information to enter into T/O data? What color will the T/O data on the MFD turn once the FADEC has accpeted it?
From the ATIS, and it will turn blue
How is the CVG controlled?
By the FADECs
What kind of bypass ratio do these engines have. What is meant by “High Bypass Ratio”
5-1 ratio.
5 parts of air are bypassed for every 1 part that goes through the compressor section.
What happens if the IGN is off and engine is OFF
No Spark, No Fuel. If you had a bad start this would be dry motoring the engine.
When will the low oil warning light come on
At 5 qts
When will the Packs temporarily shut off during normal operations
1) During Engine Start - because APU can’t simultainoulsly power the packs and start the engine.
2) On Go Around above 19°C
Will the FADECs protect you against overspeeding or over-temping an Engine? What are the limitations?
Yes, but only if the engine is already running (not during start).
What are the steps for a Cold WX Start
1) Turn IGN to on
2) Start/ Stop Selector to Start then to Run
3) If Start Fails
- Memory Items
- Abnormal Start Checklist
- Dry Motoring Checklist in QRH.
How are the components in the accessory gear box driven?
N2 via the tower shaft.
How does the CVG change the pitch of the stators to vary airflow?
By manipulating fuel pressure
What is the minimum height Max Climb (CLB) and Cruise (CRZ) is available?
500 ft AGL.
What does the FADEC do, and how many of these do we have
Full Authority Digital Engine Control are the brians of the engine.
We have 2 of these on each engine (A & B).
(Refer to FPMU schematic 2-10-10 pg 3)
What is the purpose of the centrifugal pump in the FPMU
Remove air bubbles
What happens if the FADEC senses the cross side engine is not “running”?
The FADEC boosts it’s engine to 100% thrust automatically (T/O 1).
Break down the functions of the Accessory Gear Box
1) Accessory - Component used to run the engine (oil pump, fuel pumps etc.) and/ or component driven by the engine to run another system (ie generators).
2) Gear Box - Box full of reduction gears that brings the speed of the engine to that required to run the particular compenent or accessory.
If you deploy Thrust Reversers and the FADEC senses that the TR on the Opposite engine did not deploy what will that FADEC do to the engine it is controlling?
It will not allow any more than Idle reverse to prevent assemetric thrust.
(Refer to AOM II 2-10-15 page 4)
How is the oil cooled on the EMB-145
1) Air via the ACOC
2) Fuel via the FCOC
What will the FADEC do if it senses that the engine it is controlling is not “running”
It will activate the onside electricly driven hydraulic pump to prevent a hydraulic failure.
Where is the backup location for engine data stored?
RMUs.
What are the two components of stages in a turbine?
Stators - Static Airfoils air passes over and around
Rotors - Moving (rotating) airfoils
Under what conditions are the Thrust Reverser available?
1) Weight on all 3 wheels (no speed requirement) OR
2) Weight on the mains and at least 25 KIAS (touchdown after landing).
After engine start, when is N1 a factor?
When the engine is stabilized idle and pressure is min 34 psi.
Where is the CVG located
In the inlet guide vanes and the first 5 stages of the compressor.
What are the components of the N2 compressor section, what stages do we get the HP bleed
1) 14 stage Axial Flow Compressor which is driven by
2) The 2 stage HP turbine
3) Tower shaft driving the accessory gear box
We get HP bleed at 9th and 14th stages.
What is the maximum oil quantity on the EMB-14
12 qts (may read 14)
When should you select the Max Continuous Thrust Rating? is there a time limit to this rating?
Emergency only and there is no time limit.
(Refer to FPMU schematic 2-10-10 pg 3)
When will oil bypass the FCOC?
1) If temp is greater than 93°C so it does not over temp the fuel
2) When the oil pressure is above 50psid
d = “delta p of oil”
(Refer to AOM II 2-10-15 page 4)
How is oil driven through the lubrication pumps and scavenge pumps? How many scavenege pumps are there?
Gear within the AGB drives the oil through these pumps in a single housing.
There are 5 scavenge pumps.
(Refer to AOMII 2-14-05 pg 3)
From what compressor stages is the engine bleed air “robbed”
9th and 14th stages
What is considered good pilot technique with regard to IGN knob when flying through heavy rain and/ turbulence
Turn them on to prevent flameout.
Describe the steps in an engine starting sequence
1) Air Source - Ship Air (APU or Running Eng.) or Non Ship Air (Huffer or Bottle). Non Ship air requires ignition for starting
2) Air is deliverd to the Air Turbine Starter (ATS) which drives the accessory gear box
3) Gears in gear box drive the tower shaft.
4) Tower shaft then drives the N2
5) At 14% N2 - IGN (spark) is introduced
6) At 28% N2 - Fuel is introduced
7) Eng Light off should occur in 10 secs and indicated by ITT rise
8) Normal accelaration rate is 1%/ second
*NOTE: N1 is not a factor at this point.
(Refer to FPMU schematic 2-10-10 pg 3)
What do the bypass valves do?
Relieve fuel pressure in the event of a shut down.
What is the definition of a Cold Start?
Cold Outside (10°C or less) and Cold Engine (Shut down for more than 90 mins).
What items are being lubricated by the the oil system
1) AGB
2) Aft, Center, Fwd and Fan Bearings.
If you place the Thurst Levers in the Max position, what kind of fuel flow will you always get (regardless of the Thrust Rating selected)
T/O 1
What are the steps to an External Air Start
Same as normal start, except close the crossbleed valve and turn the ignition knob to on.
Under what conditions will the FADEC auto revert to the T/O 1 thrust schedule? Why?
Below 15,000 ft with the gear down, because it wants to set you up in case you need to go-around.
What Engine make and model do we operate on the LR models? What is the thrust rating?
Allison - AE3007A1.
7426 lbs of Thrust at ISA+30°C
If you are conducting a single engine approach and want to ensure that the FADEC controlling the operating engine does not disable reverse thrust, what action should you take to over-ride the FADEC logic
Pull the Thrust Lever on the inop engine to idle to let the FADEC know you are ok with the assemetric thrust caused by max reverse on the other engine.
in what position must the Thrust Levers be for the Start/ Stop Selector be to respond to commands
Idle.
Break down the term “2 Spool Axial Flow Turbofan”
1) 2 Spool = 2 turbines (HP and LP)
2) Axial Flow = Air has linear flow through the engines”
3) Turbofan = majority of thrust comes from the fans (not turbines)
How many sets of locks do the TRs have? How many are engaged at a time?
3 sets of locks, 1 is engaged at a time and other 2 are in standby.
under what conditions will the Pneumatic Cross Bleed Valve open automatically when in the auto position
1) Any engine start where necessary
2) Anti-Ice on some airplanes (non PRSOV equipped aircraft).
What is the min height Max Continuous Thrust (CON) is available?
300 ft AGL
What are the components of the accessory gear box?
1) Hydraulic Pump
2) Oil Pump
3) OMA (Perm magnetic alternator)
4) Fuel Pump and Metering Unit (FPMU)
5) Air Turbine Starter (ATS)
6) Generators (2 for each engine).
When the start/ stop selector is in the “Stop” position what is the fuel status?
Fuel is shutoff at the engine.
What happens if all three locks fail when TRs are deployed?
FADEC will command idle.
What are the two power sources for the FADECs
1) Main electrical Essential DC Bus before 50% RPM
2) The PMA after 50% RPM.
Why are there 14 stages to the N2 compressor
Pressure increases with each stage which heats the air and allows you add more fuel to burn which gets you more energy.
How are the Turbines/ Spools driven
Exhaust Gas.
What is core lock? When might it occur and what do we do to prevent it?
1) After engine failure the housing of the compressor shrinks if it stops spinning (gets too slow) resulting in a locking of the N2 core, making re-start alomost impossible.
2) May occur during dual engine failure
3) Airspeed Min 260 kts to keep compressor spinning.
