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ERJ-145 > Powerplant > Flashcards

Powerplant Flashcards

1
Q

What is the model, type and thrust rating of the ERJ-145 LR?

A

AE 3007 A1
Turbofan 5:1 bypass ratio
7426 lb @ ISA+30

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2
Q

What is the difference between axial flow and centrifugal flow?

A

Axial flow is airflow along (same direction as) the shaft.
Centrifugal flow is where the air is accelerated outwards by an impeller then slowed down (compressed) through a diffuser.

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3
Q

What is N1?

A

The speed of the low pressure turbine.

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4
Q

What is N2?

A

The speed of the high pressure turbine.

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5
Q

How many blades on the fan of the AE 3007 A1 engine?

A

24.

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6
Q

Describe the low pressure turbine.

A

An inner shaft with the fan connected to the front and the 3 stage low pressure turbine on the back.
The rotational speed of this shaft is N1.

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7
Q

Describe the high pressure turbine.

A

An out shaft with a 14 stage compressor on the front and a 2 stage high pressure turbine on the back.
The speed of the outer shaft is N2.
This component sits in between the fan and the low pressure turbine.

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8
Q

Where does the engine bleed air come from?

A

The 9th and the 14th stage of the compressor.

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9
Q

What is the function and purpose of Compressor Variable Geometry (CVG)?

A

The CVG increases efficiency and reduces the risk of compressor stall.
Based on throttle position, the angle of attack of the air being compressed in the first 5 stages of the compressor is controlled by fuel pressure regulating the angle of the stator vanes.

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10
Q

What is the function and purpose of the Forced Mixer?

A

It combines the core and bypass air in the exhaust section of the engine.
It reduces noise and increases efficiency.

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11
Q

What is the function of the Tower Shaft?

A

It is a mechanical linkage that connects the gearbox to the N2 shaft. The rotational energy from the N2 shaft drives the gearbox.

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12
Q

What components are connected to the engine gearbox?

A 
F   Fuel Pump and Metering Unit (FPMU)
A   Alternator (Permanent Magnet Alternator (PMU))
T   Turbine (Air Turbine Start (ATS))
H   Hydraulic pump
O   Oil pump
G   Generators (2 per engine)
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13
Q

What is the purpose and function of the Air Turbine Starter (ATS)?

A

It starts the engine.
Bleed air (from the APU, ground cart or other engine) blows over an impeller (centrifugal turbine) which in turn rotates the connection to the gearbox. That rotation is transferred to the N2 turbine via the Tower Shaft.
The engines can only be started by air.

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14
Q

What is the Fuel Pump and Metering Unit (FPMU) and how is it controlled?

A

It is a mechanical-electrical unit that controls and meters the amount of fuel sent to the fuel nozzles and the Compressor Variable Geometry (CVG).
It is completely FADEC controlled.

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15
Q

What functions, other than combustion, does fuel provide for the engines?

A

Fuel pressure to operate the Compressor Variable Geometry (CVG).
Fuel to the Fuel Cooled Oil Cooler (FCOC) acts as a heat exchanger.

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16
Q

Under what circumstances would oil bypass the Fuel Cooled Oil Cooler (FCOC)?

A

If the fuel temperature exceeds 93°C.

If the pressure differential between the ingoing and outgoing oil is greater than 50 PSID (a clog).

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17
Q

What type of oil system is used in the AE 3007 A1 engine?

A

Dry sump.

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18
Q

Describe the oil pump.

A

The oil pump consists of 5 scavenger (suck) pumps and 1 pressure (blow) pump.

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19
Q

How is oil distributed from the sump to the engine?

A

A pressure pump forces oil through an oil filter, an Air Cooled Oil Cooler (ACOC), a Fuel Cooled Oil Cooler (FCOC) which is the ducted into four sections of the engine and the accessory gearbox.
Scavenger pumps draw the return oil to the sump.

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20
Q

What are the maximum and minimum oil quantities?

A

Maximum is 12 qt.
Advise maintenance via phone (no write up) if quantity is 8 qt.
Minimum is 6 qt, however if after start the quantity falls to 5 qt the engine must be shutdown.
Generally, check the oil situation on the last flight of the day and notify maintenance if a top up is required so as to avoid a delay the next day.

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21
Q

How does the pilot know how much oil is in the system and when is the indication most accurate?

A

The MFD displays the quantity.

Most accurate 5 minutes after shutdown.

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22
Q

How does the pilot know the thrust reversers have deployed?

A

REV appears in green next to the N1 digital indication.

23
Q

What happens if an uncommanded reverse thrust deployment occurs?

A

That engine’s FADEC will command that engine to idle thrust to minimise asymmetric thrust.

24
Q

Maximum reverse thrust will only be commanded if;

A

Both FADECs agree that the reverser on each engine is deployed; or
If one engine is inoperative, the inoperative engine’s thrust lever remains in the idle position.

25
Q

Given both engines and FADECs are functioning correctly, what conditions must exist for reverse thrust to deploy?

A

Thrust lever must be behind the idle stop; and

Either, weight on all wheels or weight on the main wheels only and the main wheels rotate at greater than 25 kt.

26
Q

What locking mechanism stops the reverse thrust deployment in flight?

A

A primary and secondary electro-hydraulic lock (electrically operated, hydraulically actuated); and
A tertiary electro-mechanical lock (electrically commanded, electrically actuated).

27
Q

How is a normal engine shutdown achieved?

A

Thrust Lever - Idle
Start/Stop Selector - Stop

Fuel is shutoff at the Fuel Pump and Metering Unit (FPMU).
Automatic shutdown occurs when the N2 speed falls below 54%.

28
Q

What must a pilot do after an aborted start?

A

Call for the Abnormal Engine Start checklist followed by the Dry Motoring checklist.

Perform dry motoring for a minimum of 30 seconds.
This ensures no residual fuel remains in the combustion chamber and acts to reduce the Internal Turbine Temperature (ITT).

29
Q

Under what circumstances will the thrust management system default into T/O - 1 mode?

A

Anytime the thrust levers and pushed past the detent.
On power up (this is the default setting).
Pressing the T/O thrust rating button.
Below 15 000 ft with the landing gear locked down.
If an engine failure occurs during an ALT T/O-1 take-off.

30
Q

What comprises the thrust management system?

A

The thrust management system is a combined function of the;
Take-Off Data section of the Power Plant panel
Thrust Levers
Thrust Rating Buttons

31
Q

What are the functions of the Thrust Rating buttons?

A

The Thrust Rating buttons are used to select the thrust rating given by the thrust management system.

32
Q

How does the FADEC control the N1 if the the N1 RPM signal is lost?

A

The FADEC has a non-volatile memory of the correlation between N1 and N2.
The FADEC uses this information to control a predicted N1 based on the N2 indication.
Because the system is not monitoring N1 directly, we lose power at the high end and gain power at the low end to safeguard against N1 overspeed or engine flameout.
This is called N1 reversionary control.

33
Q

How is the oil system protected from over pressurising?

A

By a pressure regulating valve.

34
Q

What is the difference between a cold and a warm bearing seal?

A

High pressure air inside the oil system (as expected during start) is able to flow through a cold seal. As the seal becomes warm, it seals completely and does not allow air to pass through.
They are installed to ensure the engine bearings receive oil at all times.

35
Q

Where is air bled from the engines?

A

From bleed valves in the 9th and 14th stage of the compressor.

36
Q

When is the 14th compressor stage bleed valve always open?

A

At low thrust settings.
When anti-icing is required.
During cross bleed starting.

37
Q

Is bleed air pre-cooled, and if so how?

A

Yes.

Air from the fan is ducted through a heat exchanger then spilled overboard.

38
Q

What reasons would substantiate action to abort an engine start?

A

Fuel flow greater than 800 lb/hr prior to light up.
No light up 10 seconds after fuel flow is introduced.
Interstate Turbine Temperature (ITT) rises rapidly, or approaches start limit (hot start).
N2 fails to increase (or decreases) for more than 30 seconds (hung start).
Unusual noise or vibration.
Engine instruments indicate abnormal engine conditions.
Visible fire or burning from the exhaust.
Oil pressure remains below 34 PSI after start is complete.

39
Q

What is Interstage Turbine Temperature (ITT)?

A

The temperature of the exhaust gases between the high pressure and low pressure turbines.
On the ERJ-145 ITT is measured inside the first stage low pressure turbine stator vane.

40
Q

What is the Permanent Magnet Alternator (PMA)?

A

The alternator connected to the engine gearbox.
It’s the only source of power for the below 10%.
Powers the FADEC when above 50% N2 (takes over from the DC Essential Bus).
Backup power for the thrust levers and thrust rating buttons.

41
Q

What are the three positions of the ‘ignition switch’ on the overhead panel?

A

OFF - both igniters are off and fuel is off.
ON - both igniters are on.
AUTO - allows FADEC to control igniters as needed (normal position).

42
Q

What is the configuration for an external air start?

A

Always start engine 2 first. It’s important to ensure that all external air coming in is directed to the Air Turbine Starter (ATS).

Packs - OFF
Crossbleed - CLOSE
Engine Bleeds - CLOSE
Ignition - ON

Then to start engine one.
Packs - As needed.
Eng 2 bleed - OPEN
Eng 1 bleed - CLOSE
Crossbleed - OPEN
Eng 2 - N2 at least 80%
Eng 1 start/stop selector - start, then run
43
Q

What should you do after any aborted start?

A

Memory items.
Call for abnormal engine start checklist followed by dry motoring checklist.
Dry motoring must occur for at least 30 seconds.

44
Q

When should a cold weather start be conducted?

A

When the temperature is 10°C or less and the engines have been shut down for 90 minutes or more.
Ensure ignition is ON.

45
Q

What does the FADEC reset button on the overhead panel do?

A

It clears any associated recorded faults. If a fault persists after the reset that fault is not cleared.

46
Q

What is the normal engine shutdown procedure?

A

Thrust lever at idle.

Start/stop selector to stop.

47
Q

When will an automatic engine shut down occur?

A

If the start ITT limit is exceeded.

If the N2 speed fails to reach 54%.

48
Q

What is the function of the thrust management setting buttons?

A 
They are used to select the following thrust ratings in flight:
T/O-1 - Full thrust
CON - Continuous thrust
CLB - Climb thrust
CRZ - Cruise thrust
49
Q

What is ALT T/O-1 mode?

A

The normal take-off setting, available only through the take-off data setting procedure. Ensures the best durability and economy of operation.
In this mode ATTCS is armed and will revert to T/O-1 mode if an engine fails.

50
Q

What is maximum continuous power?

A

The thrust setting when CON is pressed.
Available only if gear is up 300 ft above take-off altitude, or anytime 1700 ft above take-off altitude.
Inhibited on the ground.

51
Q

What is the maximum climb thrust setting?

A

The thrust setting when the CLB button is pressed.
Available only 500 ft above take-off altitude and gear not locked down, or 1700 ft above take-off altitude.
Doesn’t function if one engine is inoperative.
Doesn’t function on the ground.

52
Q

What is the cruise thrust setting?

A

The thrust when the CRZ button is pressed.
Available only above 500 ft above take-off altitude without the gear locked down, or 1700 ft.
Not available on ground, or if one engine inoperative.

53
Q

The PMA supplies power to;

A

Igniters above 10% N2.
FADECS at a minimum of 50% N2.
Thrust rating mode buttons in case of electrical emergency.

ERJ-145 (16 decks)

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