EMB-120 Powerplant Flashcards Preview

Embraer Brasilia EMB-120 > EMB-120 Powerplant > Flashcards

Flashcards in EMB-120 Powerplant Deck (84):
1

Describe the EMB 120 engines:

1800 SHP free power turbine reverse annular flow engine.

2 compressors, 2 spools, 3 shafts and 4 turbines.
Two free spools for the gas generator and a free power turbine to drive the propeller.

2

What powers the TMM?
(Turbine Machinery Module)

NH- High Speed Compressor Turbine

3

What items are on the TMM?
(Turbine Machinery Module)

HOOFS

HMU
Oil / Air separator
Oil pump
Fuel pump
Starter-generator

4

What powers the RGB?
(Reduction Gear Box)

2 Power Turbines

The RGB is located in front of the TMM above the engine air inlet. It reduces the rpm from the power turbine shaft by a ratio of approximately 15:1 and increases the torque delivered to the propeller.

5

What items are on the RGB?
(Reduction Gear Box)

(PAPAHO)

PCU (prop control unit)
Aux Gens
PCU Oil Pump
Aux Feather Pump
Hydraulic Pump
Overspeed Governor

6

What is the EEC and what does it do?

Electronic Engine Control device that works along with the HMU to modify the HMU fuel schedule to improve engine performance.
The EEC can increase fuel flow over what the HMU would schedule for the same power lever position, but only within min and max fuel flow limits of the HMU.

7

What is the HMU and what are its functions?

Hydromechanical Metering Unit (fuel flow meter).
Decides how much fuel goes to the engine up to 25% NH, then EEC takes over.
If EEC fails or in MANUAL mode, the HMU fuel alone feeds the engine.

8

What are the EEC control functions?

(HIFAN)

(HIFAN)

1) HMU de-enrichment
2) Idle speed governing
3) Fixed NH climb
4) Acceleration / Deceleration control
5) NP fuel governing

9

What engine control features change with the loss of the EEC?

No fixed NH climb
No NP fuel governing
No idle speed governing
No reverse thrust
Loss of power (which can be recovered by advancing the power lever)
Limited to FL 250
Power lever change lag time of 3 seconds compared to 1 second with EEC working

10

Describe the DESV- De-Enrichment Solenoid Valve:

Powered closed by the EEC climbing through 14,000’ to lean fuel schedule.
De-powered open by the EEC descending through 14,000’ to enrich fuel schedule.
Warning if not open by 10,000’ on the descent.
Tested during EEC check on taxi.

11

Describe the Torque Motor:

A valve that is adjusted by the EEC to provide the engine with the most ideal fuel schedule for the given conditions.
Opens at 25% NH on start and adds fuel for:
• Fixed NH climb
• NP fuel governing
• Idle speed governing
Closes when EEC turned OFF or reverts to MANUAL.

12

What causes the DESV to fail?

The solenoid fails to de-power (open).

The valve gets mechanically stuck.

13

What powers the EEC’s?

Respective Emergency DC Bus.

14

When does the EEC come on line during engine start?

25% NH.

15

What is an unsuccessful HMU solenoid check?

Turn EEC switch to MAN, NH should remain above 50%. If it drops below 50%, reset the EEC by placing switch back in TO or ON.

CLOSE the respective ENGINE BLEED.
Turn EEC switch to MAN again, check if NH remains above 50%.
If not, HMU Solenoid is locked (unsuccessful check) and takeoff is prohibited.

16

What happens when the EEC’s are put in MANUAL?

Torque motor closes.

DESV opens.

17

Why does having the EEC on lower the max takeoff altitude?

To allow more time between takeoff and DESV close.

18

What does the HMU return solenoid valve do?

Opens on start, closes at 50% NH.

Excess fuel from shutdown goes to collector tank to be siphoned back during start.

19

When does the starter become a generator?

50% NH.

20

When are you required to turn the ignition switch ON?

1) Icing
2) Moderate or severe turbulence
3) Contaminated runways

21

Hot Start

T6: rising rapidly.

NH: slow acceleration.

22

Wet Start

T6: no indication, no rise within 10 sec of CL Fx
-or-
NH: stagnates or stabilizes below 50%

23

Hung Start

NH: slow acceleration and/or may not accelerate past 35%.

Ignition not on by 25% NH.

24

Dry Start

No fuel flow indication.

T6: no rise.

25

Engine Start Malfunction Recovery:

1) CONDITION LEVER FUEL CUT OFF
2) Peak T6 NOTE
3) IGNITION switch OFF
4) Check IGNITION light out
Continue to motor for remainder of starter limit
5) START switch ABORT
6) Check Steady decrease in NH and T6.

26

On start Ignition light does not extinguish at 50%

1) START switch ABORT
2) Check Ignition light out
If not:
3) ELEC EMERG switch EMERG
4) BUS TIES 1 & 2 OFF
If light still on:
5) PWR SELECT OFF
6) R / L MAIN GENS OFF
7) R / L AUX GENS OFF
8) APU GEN OFF
9) CONDITION LEVERS FUEL CUTOFF

27

Which engine instruments work in electrical emergency mode?

1) T6
2) Torque

28

What do you do if the oil pressure reads below 55 psi in cruise?

Reduce power levers and NH below 75%

29

What’s the minimum torque for takeoff?

65%

30

What is the minimum oil temp and pressure for takeoff?

45˚C and 55 psi.

31

When does the OIL PRESS light illuminate?

40 psid.

32

List the two major outputs of the EEC.

1) Torque Motor
A variable valve that is adjusted by the EEC for the most ideal fuel schedule. Opens at 25% Nh on start to add fuel for: Fixed Nh climb, Np fuel governing, Idle speed governing. Closes at any altitude when the EEC is turned to OFF or MANUAL.

2) DESV (De-Enrichment Solenoid Valve)
Can only be full open or full closed. Powered closed by the EEC climbing through 14,000’ to lean the fuel schedule. De-powered open descending through 14,000’ to enrich the fuel schedule. Warning at 10,000’ if it doesn’t open. Can fail for two reasons: Mechanically stuck or Solenoid fails to de-power “open.” Opens at any altitude when the EEC is turned to OFF or MANUAL.

• EEC’s are powered by the respective Emer DC Bus.

33

During a normal start, oil pressure should rise by?

NH = 35%

34

During start, what happens at 50% Nh?

1) The Starter becomes a Generator- at 50% Nh the GCU (Generator Control Unit) automatically opens the start contactor allowing the starter-generator to operate as a generator.

Ignition light out.

35

Maximum continuous power setting is ____ Torque or ____ T6, whichever comes first.

• 100% Torque
• 800˚C T6

36

Cruise max torque with Np at 100 % is what?

72%

37

For the PW118A maximum continuous NH is what?

102%

38

Talk about Nh speed control

The EEC on the PW118 A/B engine on the Brasilia, is programmed to maintain a constant NH relative to power lever angle. This is true in all phases of flight, not just in climb.
The EEC will vary fuel flow and, hence, other engine parameters to achieve this.
In actual operation during a climb, a pilot will observe small variations in torque and increasing T6 until the mid teens. Then torque will decrease noticeably as T6 continues to increase.

39

Talk about idle speed governing:

IDLE SPEED GOVERNING is the operating mode when the aircraft power lever is aft of flight idle and the condition lever is in FEATHER. A quadrant microswitch at the FEATHER position sends a signal to the EEC which maintains an NH of 62%.
With the power lever at ground idle, the Np will be approximately 20%. This is the normal configuration for the various feather checks. It is not necessary for the Np to be exactly 20%; rather, each propeller should be consistent with itself and feather to the same value each time.

40

Talk about Np FUEL GOVERNING. When is it used?

Np FUEL GOVERNING is the normal ground operation/taxi mode with the power levers forward of full reverse. Np speed is determined by quadrant micro-switches at the MIN and MAX positions. MIN commands the EEC to maintain an Np of 50%: MAX commands the EEC to maintain and Np of 65%.
As the power levers are moved in the ground range forward of full reverse, Nh will vary with blade angle as the EEC modulates fuel to maintain a constant Np.

41

What happens when there is a total EEC failure:
FLIGHT CONDITION: Any
Red EEC light “Engine Control” aural:
White MANUAL Light:
Torque Motor position:

Red EEC light “Engine Control” aural
White MANUAL Light ON
Torque Motor Closes

42

What happens when the HMU DESV Fails:
FLIGHT CONDITION: Went above 14,000’ Descent through 10,000’
Red EEC light “Engine Control” aural:
White MANUAL Light:
Torque Motor position:

Red EEC light “Engine Control” aural
White MANUAL Light OFF
Torque Motor Normal

43

What happens with a fail fix:
FLIGHT CONDITION: Sensor loss below 14,000'
Red EEC light “Engine Control” aural:
White MANUAL Light:
Torque Motor position:

Red EEC light “Engine Control” aural
White MANUAL Light OFF
Torque Motor Freezes

44

Where does the main engine oil pump send oil?

o PCU pump for propeller operation
o Engine bearings for lubrication

45

Where do you find the Battery Start procedure?

SOP Appendix A Supplemental Procedures

46

How much does the RGB reduce the rpm from the power turbines?

15 : 1

47

What MAP lights comes on when the engine fails?

o OIL PRESS
o FUEL
o ELEC
o EEC WARNING

48

How many quarts of oil does the Brasilia hold?

28 quarts per engine

49

What type of oil does the Brasilia use?

Mobile Jet 2

50

When should you check the oil level for an accurate reading?

o Between 15-25 min after shutdown
o Check for oil level between add 1 and 2

51

On a normal start when should oil pressure rise?

NH = 35%

52

What are the T6 Limits?
o Takeoff Max continuous:
o Takeoff Emerg 5 min max:
o Start: 816˚C - 850˚C:
o Start: 850˚C - 950˚C:
o Warning:
o SkyWest climb limit:

o Takeoff Max continuous: 800˚C
o Takeoff Emerg 5 min max: 816˚C
o Start: 816˚C - 850˚C: 20 seconds
o Start: 850˚C - 950˚C: 5 seconds
o Warning: 816˚C
o SkyWest climb limit: 720˚C

53

What are the Torque limits?
o Takeoff Max continuous:
o Takeoff Emerg 5 min max:
o Transient (up to 20 sec):

o Takeoff Max continuous: 100%
o Takeoff Emerg 5 min max: 110%
o Transient (up to 20 sec): 120%

54

What is the max cruise torque for the following NP settings?
o NP – 100%
o NP – 90%
o NP – 85%
o NP – 80%

o NP – 100%: 72%
o NP – 90%: 80%
o NP – 85%: 84%
o NP – 80%: 84%

55

What are the following NH limits?
o Takeoff max cont (118A):
o Min NH for ops of deice equip:

Takeoff max cont (118A): 102%
Min NH for ops of deice equip: 80%

56

What are the following Oil Temperature limits?
o Min start (red radial):
o Takeoff max cont (118A):
o Transient (20 min, 118A):
o Min to unfeather prop :
o Min to feather prop:

o Min start (red radial): -40˚C
o Takeoff max cont (118A): 45˚C to 115˚C
o Transient (20 min, 118A): 115˚C to 125˚C
o Min to unfeather prop: 0˚C
o Min to feather prop: 10˚C

57

What are the following Oil Pressure limits?
o Min ground idle (red radial):
o Power flight idle & NH <75%:
o Takeoff max cont:
o Elec Fx pump duty cycle:

o Min ground idle (red radial): 40 psid
o Power flight idle & NH <75%: 40 to 55 psid
o Takeoff max cont: 55 psid to 65 psid
o Elec Fx pump duty cycle: 20 sec/ 6 consecutive cycles

58

What do the engine labyrinth seal do?

It’s a seal of air that holds oil on the engine bearings in the hottest part of engine

59

On a hot day, climbing through light to moderate turbulence at a rate of 400 ft/min, the right T6 reads 730˚C. What should you do with the engine power?

Increase T6 to 800˚ for performance

60

Upon starting the left engine, the T6 rises to 855˚C for 6 seconds. How much time must elapse before another start attempt is made?

Exceeds limitation- call Maintenance

816˚C-850˚C: 20 seconds
850˚C-950˚C: 5 seconds

61

Upon starting the right engine, the T6 climbs rapidly. As it passes 845˚C, you pull the Condition Lever to FUEL CUTOFF, but the T6 continues to climb past 970˚C. What do you do next?

Pull Fire Handle, QRC

62

How long do the engines need to cool down?

3 minutes after Condition Levers are set to MIN.

63

How long do the props need to be in feather before shutdown?

20 seconds, included in the 3 minutes.

64

Where does excess fuel done with on shutdown?

It is purged into a drain collector tank. On start this fuel is put into the main tanks.

65

When does the BETA light illuminate?

Anytime the blade angle goes below 12.6°.

66

How does the Autofeather arm?

1) Autofeather switch ON
2) Power Levers above 62% PLA
3) Tq above 62° within 8 sec

67

What do the power lever micro switches send information to? (5)

1) Landing Gear Warning
2) Autofeather arm (62°)
3) Pre-pressurization
4) T/O Warnings
5) Secondary Low Pitch Stop micro switch

68

Synchrophaser induces which propeller Np?

Right propeller to oscillate together with left prop up to 2%.

69

Is the Aux feather pump on the Emergency bus?

Yes

70

How many fuel nozzles are there per engine?

14; 10 primary, 4 secondary.

71

How many igniter plugs are there?

2 igniter plugs.

72

Torque is sensed by:

Torque is sensed by measuring the angular twist between two points

73

Failure of the Torque Signaling unit on takeoff will result in:

Failure of the Torque Signaling unit on takeoff will result in an a Propeller feather and a resulting over torque condition.

74

AN ILLUMINATED IDLE UNLOCK LIGHT MEANS THAT:

The amber “Idle 1 & 2 UNLK” lights, on the glaresheild, indicate that the flight idle solenoid for it’s respective power lever have disengaged in flight. At this point if you lift the Trigger to bypass the gate on a power lever, you would have nothing impeding it from going below flight idle. The breakers that protect the solenoids are under a piece of Plexiglas on the console on the captains side. It is a required safety check FFOD task for the Captain, to make sure they are pushed in.

75

THE MAIN HYDRAULIC PUMP IS
LOCATED ON AND POWERED BY:

The Reduction Gearbox RGB

76

THE MAIN GENERATOR IS LOCATED ON AND POWERED BY:

The Turbine Machinery Module TMM

77

THE MAIN ENGINE OIL PUMP IS LOCATED ON AND POWERED BY:

The Turbine Machinery Module TMM

78

When does oil pressure come alive and why?

Minimum Pressurizing Valve oes not open until 30%-35% Nh. This is when the oil gauge comes alive. Reason for not allowing oil to bearings prior to this is because the labyrinth seals do not have enough P3 air to keep oil contained in the bearings. If the Main Oil pump fails the prop will Pitchlock because there will be no oil to the PCU pump.

79

THE MINIMUM ENGINE OIL TEMPERATURE FOR TAKEOFF IS:

Minimum oil temperature for takeoff is 45ºC

80

Minimum oil pressure at ground or flight idle is:

Minimum oil pressure at ground or flight idle is 40 psid.

81

Minimum oil pressure for takeoff is:

Minimum oil pressure for takeoff is 55 psid.

82

Why do some EEC switches say MAN, TO, CL, CR?

The Embraer engineers originally planned to have three optimum fuel schedules: TO for takeoff, CL for climb, and CR for cruise. However, only one was developed. Consequently, all three positions have the same fuel scheduling. Later versions of the switch are labeled MAN and ON. The EEC controlled components inside the HMU are the torque motor and the de-enrichment valve.

83

What is the purpose of FAIL FIX?

The purpose of FAIL FIX is to provide stable engine power at V1 or shortly thereafter for a specific EEC failure condition.

Two requirements satisfy this condition:
1. The EEC has a failed peripheral sensor, and
2. The aircraft is below 14,000’ msl.

When these two conditions are satisfied, the HMU torque motor valve is fixed at the last position until the selector is switched to MANUAL.

This prevents the rapid power roll back associated with the full EEC failure. However, the FIXED NH feature of the EEC is also eliminated. As climb is continued in the fail fix mode, the power lever
should be advanced to maintain a constant torque.

If the fail fix condition occurs below V1, an abort can be made, but fuel flow will remain high on the engine until the selector is switched to MANUAL.

84

CRUISING TO SBA AT 6000 FT. MSL,THE FOLLOWING WARNINGS OCCUR; RED EEC LIGHT ILLUMINATES, TRIPLE CHIMES AND VOICE WARNINING “ENGINE CONTROL”. THE MANUAL LIGHT IS NOT ILLUMINATED. WHAT IS THE PROBLEM?:

Fail Fix