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Mesa E-175 Oral Prep 2022 (just updated) > Electrical > Flashcards

Electrical Flashcards

1
Q

List the AC Power Components

A
  1. (2) IDGs (primary) 115 VAC, 400 Hz, 40 KVA
  2. (1) APU115 VAC, 400 Hz, 40 KVA
  3. (1) AC GPU Receptacle 115 VAC, 400 Hz, 40 KVA
  4. (1) RAT - 115 VAC, 400 Hz, 15 KVA
  5. (1) Inverter 250 VDC to 115 VAC direct to AC STBY BUS
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2
Q

List AC Power Priority

A
  1. Onside
  2. Inside (APU)
  3. Outside (AC GPU)
  4. X-Side (Other IDG)
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3
Q

Can one IDG power both AC Buses?

A

Yes, on ground and in-flight

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4
Q

Can the APU power both AC Buses?

A

Yes, on ground and in-flight up to FL330

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5
Q

Can the GPU power both buses?

A

Yes

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6
Q

What does the DISC position on the IDG do?

A

Disconnects IDG from CSD. If this fails it mechanically shears off the CSD from the IDG

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7
Q

When do you know you need to DISC the IDG?

A

LOW Oil pressure low
HOT Oil temp high
Amber light is on

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8
Q

Flight crew can reconnect IDG after DISC has been engaged?

A

No, that is a MX function on the ground

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9
Q

What (2) combinations provide power to accomplish APU START?

A
  1. BATTs 1 & 2
  2. BATTs 1 and DC GPU
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10
Q

Which Battery controls the APU’s FADEC?

A

BATT 1

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11
Q

Which battery is isolated from the network during APU START to exclusively power the APU START BUS?

A

BATT 2

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12
Q

What is the minimum VDC required during the Safety & Power On Checklist to consider APU Start?

A

22 VDC

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13
Q

What is the minimum VDC required to close the battery contactor?

A

18 VDC

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14
Q

What is the min BATT 2 temp for APU start?

A

-20º C

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15
Q

The APU is a primary AC source (T/F)

A

False

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16
Q

How many ways can the AC GPU be turned on?

A
  1. AC GPU panel (AC/DC GS Panels & TRU 1)
  2. (1) Opp. FWD Lav (AC/DC GS Panels & TRU 1)
  3. (1) Switch Cockpit Overhead Panel (Powers whole aircraft network)
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17
Q

When does the Static Inverter turn on?

A

Whenever AC power is lost to power the AC STBY Bus which powers Igniters 1A and 2A

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18
Q

There is an altitude and speed restriction for deployment of the RAT (T/F)

A

False, only speed

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19
Q

When will the RAT deploy automatically?

A

When both AC buses lose power during an electrical emergency to supply ESS Buses

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20
Q

What is an example scenario you would manually deploy the RAT?

A
  1. Auto RAT deployment doesn’t work
  2. Dual engine failure (1. A/S 250 or > and 2. RAT MAN Deploy)
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21
Q

How long does the RAT take to deploy and are we out of power during that time period?

A

8 seconds to fully deploy and the batteries power the system

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22
Q

What is the min RAT speed to avoid load shedding?

A

130 kts

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23
Q

What happens under 130 kts for the RAT?

A
  1. RAT only powers AC ESS
  2. BATTs provide power only to DC ESS and AC STBY (thru static inverter)
  3. Load shedding continues until AC ESS is no longer powered
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24
Q

What (3) elements comprise the DC Power System

A
  1. (3) TRUs (primary) 28VDC, 300A
  2. (2) NiCad Batteries 22.8 VDC, 27AH
  3. 1 DC GPU 28 VDC
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25
Q

What does the TRU do?

A

it rectifies AC power at 115 VAC to 28 VDC

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26
Q

Do the TRUs work in isolation from one another?

A

yes

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27
Q

The batteries are the primary DC power source?

A

No, the (3) TRUs are

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28
Q

How are the BATTs charged?

A

Via any AC power source through the TRUs

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29
Q

How long do you have battery power during an emergency?

A

10 mins

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30
Q

What does the BATTs backup?

A

DC ESS Buses and AC STBY

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31
Q

Can the DC GPU charge BATT 2?

A

No, only BATT 1

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32
Q

Which battery does the DC GPU replace during an APU Start?

A

Hooks directly to APU START Bus and replaces BATT 2

33
Q

The __ collect and confirm the power is safe and then send it to the ____ for distribution

A

ICCs, SPDAs

34
Q

How many ICCs are there?

A
  1. LICC (Mid E-Bay)
  2. RICC (Mid E-Bay)
  3. EICC (FWD E-Bay)
  4. AICC (AFT E-Bay)
35
Q

How many SPDAs are there and where are they located?

A
  1. SPDA 1 (FWD E-Bay)
  2. SPDA 2 (Mid E-Bay)
36
Q

Thermal/Electronic CBs apply to what?

A

ICCs Thermal CBs (thermal 1st line of defense)
SPDAs Electronic CBs (elec. 2nd line of defense)

37
Q

Thermal CBs are resettable in the MCDU?

A

False only Electronic CBs in the SBDA can be reset by the MCDU

38
Q

Which part of the electrical system performs BITs?

39
Q

What is on DC HOT Bus 1?

A
  1. Eng 1A/2A Fire EXT
  2. Eng FSOV 1
  3. HYD SOV 1
  4. Eng 1 Oil Level Indication
  5. Courtesy/Service Lights
  6. DC Ceiling Lights
40
Q

What is on DC HOT Bus 2?

A
  1. Eng 1B/2B Fire EXT
  2. Eng FSOV 2
  3. HYD SOV 2
  4. Eng 2 Oil Level Indication
  5. CMC
  6. Panel Refuel
  7. Water and Waste System
41
Q

How many systems make up the electrical system and why?

A

2 systems designed for redundancy and fault isolation

42
Q

What happens if a power generating source fails?

A

The bus ties auto connect to provide no system degradation

43
Q

How does the IDG maintain a stable power output?

A

The Constant Speed Drive (CSD) attaches the IDG to the AGB

44
Q

What monitors and controls the IDGs?

A

A Generator Control Unit (GCU) per IDG, which is a type of Continuous BIT

45
Q

What is primary purpose of the AC Generators?

A
  1. Provides power to AC Buses and AC ESS Bus
  2. Those power the (3) TRUs
46
Q

Can the APU replace a failed IDG?

A

Yes, start at 30,000 and max op ALT at 33,000

47
Q

How is it known that an AC GPU is hooked up to the airplane and ready to provide electricity?

A
  1. GPU button displays AVAIL and GPU icon is present on the electrical synoptic page
  2. Once GPU button is pushed in, the button will display IN USE provided another AC power source is not available
48
Q

If the airplane is using the AC GPU and the APU is started what should the pilot be sure to do?

A

Deselect the GPU botton before the next GPU connection

49
Q

How long will the batteries last with no recharging?

A

10 minutes

50
Q

What is the purpose of the DC GPU receptacle?

A
  1. For APU start when battery VDC < 22 VDC
  2. if battery 2 temp is < -20ºC
51
Q

Is there a total loss of power during RAT deployment?

A

No, BATTs supply power to DC ESS buses and AC STBY (through static inverter) during the 8 seconds

52
Q

What does the RAT power

A

All the ESS Buses
AC ESS Bus —> TRU ESS –> DC ESS Buses 1,2,3

53
Q

What is an electrical control device, which provides power distribution and protection electrical loads

A

Integrated Control Center (ICC)

54
Q

An electrical load-management unit (powered by the ICCs) that distributes electrical loads to aircraft systems according to system logic and performs BITs on many components?

A

Secondary Power Distribution Assembly (SPDA)

55
Q

What are the 3 types of BITs?

A
  1. Continuous Tests
  2. Fault-Initiated Tests
  3. Initiated Tests
56
Q

What 3 systems/components have BITs?

A
  1. GCUs
  2. AGCU
  3. SPDAs
57
Q

What is on the LICC?

A
  1. AC BUS 1 with BTC 1
  2. AC/DC GND SVC
  3. TRU 1
  4. DC BUS 1 with DCTC 1
58
Q

What is on the RICC?

A
  1. AC BUS 2 with BTC 2
  2. TRU 2
  3. DC BUS 2
  4. DC ESS BUS 2 with ETC 2
59
Q

What EICAS message is displayed if RAT Fails to deploy?

A

BATTERY DISCHARG

60
Q

Where is the static inverter located?

61
Q

What kind of power does the inverter create?

A

AC power, 115 VAC, Single Phase, 400 Hz

62
Q

Where are the batteries located?

A

BATT 1 = FWD E-BAY
BATT 2 = AFT E-BAY

63
Q

What is located in the FWD E-Bay?

A
  1. BATT 1
  2. SPDA 1
  3. EICC
  4. Static Inverter
  5. MAUs 1 & 2
64
Q

What is located in the MID E-Bay?

A
  1. SPDA 2
  2. RICC & LICC
  3. MAU 3
  4. MRCs (radios/TDRs)
65
Q

What is still powered when just the batteries are powering the system (elec. emer)? When else are just these instruments avail?

A
  1. DU 2 and 3
  2. IESS
  3. Clock
  4. MCDU 2
  5. CCD 1
  6. Audio Panels
66
Q

What is the EICAS message ELEC EMERGENCY indicate?

A

AC Main Buses have been deenergized

67
Q

Why is 3 phase power used over single phase?

A

3 phase power is constant at every instance nd the average power is 1.5 times the maximum power of one phase.
2 phase average power is equal to max power of one phase
1 phase average power is equal to 0.5 the max power of one phase

68
Q

What monitors electrical power for the AC GPU on the ground?

A

EPM or electronic power module located in the LICC

69
Q

Where is the location of the RAT GCU, AGCU, and GCU 1 and 2?

A

RAT GCU located near RAT, AGCU and GCU 2 are in RICC and GCU 1 is in LICC

70
Q

Does the electrical configuration of the DUs change after RAT has deployed? (ie. do you get DU 1, 4, or 5 back or anything else?)

A

No, DU 2 becomes a PFD, reversionary capability is lost, so no way of checking MFD for systems and status page

71
Q

What does NBPT (no-break power transfer) achieve?

A

Auto-parallels electrical power from 2 sources to verify meeting necessary electrical requirements before taking one generator offline

72
Q

When does BATT 1(2) OVERTEMP EICAS message come on?

A

70˚ C for at least 2 seconds

73
Q

How many slots do MAUs 1, 2, and 3 contain?

A

MAU 1 = 20 slots
MAU 2 & 3 = 16 slots

74
Q

What are root message priority?

A
  1. Warning (Electrical Emergency is only warning)
  2. Elec. Buses
  3. MAU Fails
    So in essence, all Root Messages are electrical related
75
Q

What is the name of the electrical wiring that connects and integrates the ICCs, SPDAs, and MCDUs together?

76
Q

What kind of electronic CBs are located in the SPDAs?

A

SSPCs or Solid-State Power Controllers

77
Q

Where does the EICAS get its Battery Temp info from?

A

MAUs which receive info from Temp sensors inside the batteries

78
Q

How many cells do each battery contain?

A

19 semi-open NiCad cells connected in a series by copper bus bars

Mesa E-175 Oral Prep 2022 (just updated) (20 decks)

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