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Mesa 175 systems > Electrical 175 > Flashcards

Electrical 175 Flashcards

1
Q

How many networks make up the electrical system on the airplane? Why?

A

2 independent networks
redundancy and fault isolation

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2
Q

what happens if a power generating source fails?

A

bus ties automatically connect to provide no systems

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3
Q

what components power the AC system?

A

2 integrated drive generators (IDGs) (40kVa, 115 VAC, 400 Hz)
Auxiliary power unit (APU)
Inverter (250VA - 28V DC to 115 VAC)
Ram Air Turbine (RAT 15kVA, 115 VAC, 400 Hz)
AC GPU receptacle

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4
Q

What powers the IDG?

A

respective AC BUS

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5
Q

What is Batt 2’s primary purpose?

A

Start APU

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6
Q

What is the minimum battery temperature for APU start?

A

-20 degrees C

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7
Q

What happens when you hit the GPU AVALi button?

A

it turns from Aval to In Use.
The AC GPU has priority over the batteries to power the electrical system
Correct frequency, amperage, voltage

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8
Q

When does GPU available button turn on?

A

External GPU cart is properly plugged in
Proper amperage, voltage, frequency

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9
Q

What’s the AC priority

A

Onside (IDG)
Inside (APU)
Outside (GPU)
Cross side (IDG)

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10
Q

How does ground service and maintenance get power for mx and flight preparation?

A

Pushing the respective button located on the front ramp panel or on the flight attendant panel at forward right galley

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11
Q

what is the purpose of the inverter? What bus is it connected to ?

A

converts 28VDC from batteries to 115 VAC to supply the standby AC bus when an AC power source is not available

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12
Q

When does the RAT automatically come online?

A

Whenever AC power sources are not powering AC buses.

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13
Q

What are the batteries powering during the 8 seconds of RAT deployment?

A

DC Ess Buses and Standby AC bus

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14
Q

Which pump for RAT drive and what does it do?

A

AC motor driven pump 3A for primary flight control tasks. high lift system actuation and power for essential avionics, communication and battery recharging.

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15
Q

What is the min speed for RAT? What does the RAT power?

A

130 kts
DC essential bus 1, 2, 3
AC essential bus
AC standby bus
Hot bat bus 1
Hot bat bus 2

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16
Q

What components power the DC system?

A

2 NiCad batteries (24 volt, 22 to start)
3 Transformer Rectifier Units (TRU) (rated at 300A, convert 115 AC to 28VDC)
DC GPU receptacle

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17
Q

What is the purpose of the DC GPU?

A

to start the APU if batteries are below 22 V and temperature is below 20 degrees C.

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18
Q

How many TRUs? Do they rely on each other or isolated?

A

3 and in isolation. Buses will automatically be powered by the remaining TRUs as long as the DC BUS TIES toggle switch is selected to AUTO

19
Q

What does TRU 1 power?

A

provides DC power to DC BUS 1, DC Ess Bus 1, DC GND SVC Bus, HOT bat bus 1 and battery 1 charging

20
Q

What does TRU 2 power?

A

provides DC power to DC BUS 2, DC ESS BUS 2, HOT BATT BUS 2 and battery #2 charging

21
Q

What does TRU Ess power?

A

DC power to DC ESS BUS 3

22
Q

what charges the batteries?

A

any AC source thru the TRUs, including the RAT and AC GPU.

23
Q

How long do batteries last in an emergency?

A

10 min

24
Q

How does IDG maintain a stable power output

A

a constant speed drive (CDS) attaches the IDG to the AGB (Accessory gear box)

25
Q

what monitors and controls IDGs

A

each has a generator control unit (GCU)

26
Q

What causes the amber IDG light on the overhead panel to illuminate?

A

High oil temperature
Low oil pressure

27
Q

What is the primary purpose of the AC generators?

A

power the AC buses, AC essential bus which powers the 3 TRU (1,2, essential)

28
Q

whats the minimum battery voltage to close the battery bus ties?

A

18 volts

29
Q

what battery is used for APU start?

A

battery 2

30
Q

what is the purpose of the inverter?

A

converts 28 VDC from the 115 VAC to power the AC standby bus when AC source is not available

31
Q

What is on the AC standby bus?

A

engine exciters 1A and 2A

32
Q

When is the RAT icon displayed on the electrical synoptic page

A

when the RAT is deployed

33
Q

What manages the electrical system?

A

4 integrated control centers (ICC)
Left ICC
Right ICC
Emergency ICC
Auxiliary ICC

34
Q

What is an ICC?

A

an electrical control device which provides power distribution and protection for electrical loads.

35
Q

what is SPDA?

A

secondary power distribution assembly. an electrical load-management unit, powered by ICC, that distributes electrical loads to aircraft systems according to distribution logic and performs BITs (built in tests) on many components

36
Q

Can the flight crew reset the ICC and SPDA remote electronic CBs?

A

ICC CB’s can only be reset by maintenance. SPDAs can be reset by crew in MCDU

37
Q

What are LRU’s and LRMs

A

LRUs and LRMs allow quick access and easy replacement of electrical components. plug and play. take a module out and put a new one in with new system logic.

38
Q

What’s on the AC essential bus?

A

flaps/slats
hydraulic pump 3A
Ac fuel pump 2A

39
Q

Whats on DC hot bat bus 1?

A

Courtesy/service lights
ceiling lights
engine 1 oil level indication
engine 1A/2A fire extinguishing
engine fuel SOV 1
Hyd SOV 1

40
Q

What’s on DC hot bat bus 2?

A

CMC
Engine 1B/2B fire extinguisher
engine fuel sov 2
hyd system sov 2
panel refuel 3
water and waste system

41
Q

What turns on when you put Batt 1 on, Batt 2 AUTO?

A
42
Q

what’s on AC standby Bus?

A

engine 1 exciter 1A
engine 2 exciter 2A

43
Q

What is shed first when we load shed?

A

galleys and right windshield heating

44
Q
A

Mesa 175 systems (15 decks)

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