Electrical Flashcards
1
Q
Alternate Sources of Power for Ground Service Bus?
A
APU Generator
External Power
2
Q
Ground Service Bus Powers…
A
Main Battery Charger
APU Battery Charger
Misc. Cabin & System Loads
3
Q
Ground Handling Bus Can Be Powered When?
A
Only on the ground
4
Q
Ground Handling Bus Only Works If What Are Powered?
A
APU Generator
or
External Power Source
5
Q
Ground Handling Bus Provides
A
Cargo Handling Capability
Equipment Energized During Ground Ops
6
Q
If Power is Lost to Both Main AC Busses, the Captains Flight Instruments are Powered by the
A
Hydraulic Driven Generator
7
Q
What Powers the Transfer Busses Normally?
A
Their Associated MAIN AC BUSSES
8
Q
What Powers the Transfer Busses is both AC busses are unpowered?
A
HDG
9
Q
Load Shedding That May Be Observed Prior to Engine Start (3)
A
Electric Hydraulic Pump
Center Tank Fuel Pumps
Utility Busses
10
Q
Load Shedding That May Be Observed During Non-Normal Operations (3)
A
Utility Busses After a Generator Failure
Center Tank Fuel Pump after engine start
Cabin ceiling lights after engine failure
11
Q
The Battery/Standby Power System Consists of the Following Busses (4)
A
Hot Battery Bus
Main Battery Bus
Standby AC Bus
Standby DC Bus
12
Q
Name Some Things on Hot Battery Bus
A
Fire PROTECTION (extinguisher Bottles) Captains Clock APU Fuel Valve Spar Fuel Valve Parking Brake Valve Man Deployment of the RAT All 3 IRUS
13
Q
Prior to establishing electrical power, the main battery powers what?
A
The Hot Battery Bus
14
Q
After electrical power is established, what powers the Hot Battery Bus?
A
Main Battery CHARGER
15
Q
After Electrical Power is established what powers the battery bus? What provides a backup source of power?
A
The Left DC System
The Main Battery
16
Q
When do we Load Shed?
A
- During hydraulic pressurization- load sheds c2 pump and two galley busses
- During engine start- ignition goes to ground- lose both galleys both utilities and left electric demand pump
- During inflight with 1 generator down- we load shed galley utility busses and Boeing logic controls the rest
17
Q
What does the Battery DISCH light illuminated mean?
A
Battery is discharging
If EICAS powered: MAIN BAT DISCH-
30 MINUTES STANDBY POWER!
18
Q
What Hydraulic System Powers the Hydraulic Driven Generator?
A
Center Hydraulic System
19
Q
Hydraulic Driven Generator provides AC power to what? (4)
A
Left AC Transfer Bus (Captains)
Right AC Transfer Bus (FO)
Standby AC Bus (through the left AC transfer bus)
The Captains Flight Instrument Transfer Bus
20
Q
What happens when you bring the throttles aft of the interlock position?
A
Autothrottles Disengage
Speedbrakes Deploy
21
Q
REV ISLN light means what?
A
Fault in the reverser system
this light is inhibited in flight
22
Q
What happens to the APU bleed valve at 17000’?
A
It CLOSES
23
Q
When Arming Speedbrakes what must you have to make them go off on the ground
A
Main Gear Logic On the Ground
Wheel Spin Up
Thrust Levers to Idle
24
Q
What are flap positions and their speeds?
A
UP
1 Just Slats in takeoff position 250
5 Takeoff Flap Position (most common) 230
15 Takeoff Flap Position 210
20 Takeoff Flap Position/Non-Normal Operation 210
25 Normal Landing Flap Position 180
30 Normal Landing Flap Position 170
25
Cold Dark Airplane
1. Check to make sure mx done
2. Check logbook
3. Supplemental Power Up Procedures 6.1
26
No Switches on in Electrical System. Whats powered?
Hot Batt Bus
Main Batt Bus
Stb AC Bus
Stb DC Bus
27
What bus needed to fuel the airplane?
Hot Battery Bus
When you open fueling panel door it uninhibits the the 2 pumps in the Below 50% n2
Switch is left side of the wing - Normal to BATT
Standby Light will be in OFF position
28
External Power- Tell me about it
1 ON forward aft nose on the right
| Leave switches in on position- Boeing System Logic
29
When does DC Bus Tie work?
When you lose a T/R
30
What do the GEN CTRL BREAKERs do?
Protects my bus from bad power coming out of generator- Bus is so important
Also protects generator from a bad bus
31
What turns on the GEN Drive light?
HOT
LOP
There is no auto disconnect
Not able to be reconnected in flight
Only by MX on the ground
32
How do people vacuum the airplane without me there?
AVAIL light on on the overhead is showing with ground Power plugged in
Ground Service Switch in the forward left galley ON
33
Walk me through an APU Start
1. APU selector to START then spring loads back to ON
2. ECU begins start sequence
3. FAULT light depicted ON then OFF- (APU fuel valve went full open)
4. RUN light will flicker twice (2 self test of circuitry per each battery)
5. RUN light will come on at 95% and stay on steady- APU is now started
34
APU Starting Limitation
3 start attempts in 1 hour allow 1 min cooling between attempts
35
How do you get the APU to go from External Power to now powering the busses?
You turn external power switch to OFF to get APU to take over
All busses now powered by APU except GROUND HANDLING BUS
**The ground handling bus will still provide power
36
When will Ground Handling Bus stop running?
1. When you go into flight via the main gear ground logic (therefore it only works on the ground) Example: Packs off Takeoff-
2. Disconnecting External Power
3. Shutting OFF APU
37
After you disconnect ground power, what is the logic of the electrical system getting power?
Start the right engine, R Main AC bus wants to use the right generator for power obviously –
The Left Main Bus uses the APU Still
Start left engine, L Main AC bus will go to the Left generator for power
L & R AC BTB open to prevent paralleling
IF you turn off APU now you don’t have Ground Handling anymore.
38
What is shed during an engine start?
C2 Pump & Galley Power
39
External Power Switch AVAIL Illuminated means what?
1. Power Connected
2. Acceptable (voltage and frequency)
3. Ground Handling Bus is now energized
40
External Power Switch ON Illuminated means what?
External Power connected to a Main Bus- (you pushed it and wanted it to connect to a Main Bus)
41
APU Generator OFF Light Indicates?
Generator Manually Selected OFF
or
FAULT on APU Generator
42
What is the APU Shuffle?
Procedure to prevent inadvertent shutdown by overcoming the check valve
43
Walk me through the APU Shuffle.
1. Turn Bleed Air switch for APU OFF – (Prevents air from going into 4 ducts)
2. Packs from AUTO to OFF- (closes both pack valves)
3. Turn APU bleed Air Switch back to ON (give control back to Boeing to populate 4 ducts)
44
What is the Engine Start Duty Cycle?
Continuous for 5 minutes
| Must Cool for 30 seconds per minute of operation
45
When I select GRND during engine start, what will the APU do?
Increase pneumatic pressure during start.
46
Walk me through an engine start
Take right start selector from AUTO to GND- it stays there- arms ignition and opens right start valve
When VALVE light goes on then off- the valve is fully open
Captain starts 5 minute duty cycle clock
Check for 21 min PSI on the DUCT pressure PSI
Go to Bottom eicas look for N2 and oil pressure
N2 becomes stabilized and less than 1% change in 5 seconds Max motoring on N2- Need to go past little tick on N2
Fuel Control Cutoff to RUN (energizes ignition-gives you light-off)
Time 25 second light off for GE engine-
EYES NEED TO BE HERE! Monitor! Look at SPAR VALVE light and ENG VALVE indicating fully open-you have control of your engine
Go to Primary and look for EGT going up, light off and normal start indications (look for hot, hung, no light-off)
@ 50% N2- starter will automatically click back from GND to AUTO-This is called Starter Cutout
Starter is at normal idle no longer energized-start valve closed
When magenta tick that is 750 EGT goes away you can say “normal start”
(that 750 degree magenta tick initially shows up with AC power and fuel cutout switches selected)
47
What will the APU bleed air valve do when the engine start is over?
CLOSE- it is only OPEN during start
48
Just started right engine from APU- what is the position of the R Engine Bleed Air Valve
WIDE OPEN!
APU Bleed Air Valve?- Closed
Why? Boeing logic.
Must have air going through all 4 ducts to make sure all 11 items work
49
When I start left engine- what do I load shed?
Left Utility & Galley Power
50
When I start right engine- what do I load shed?
Right Utility & Galley Power
51
What is required of me for Preflight? HOBOS
H yd Quantity (No Refill) No RF-must not see “RF”
O xygen (1250 &1350) See supplement if you have more people
B rake – Parking Brake has to be SET- Can now see 16 brake wear pins check on preflight (none on nosegear)
O il QTY (17 qts)
S tatus Msgs- Fix, consider-CLEAR Them! (if you can’t clear call mx)
52
3 Chances for system to Load Shed are
1. Overload- Occurs during hydraulic power (prior to starting engines, you’re on APU and everything powered normally. )
2. Engine Start- Selecting ground you load shed L electric demand pump and both utility busses L & R. Only on side No more load shedding upon the start of an engine.
3. Loss of Generator (single AC Power Source)- Both generators powering respective busses- if an AC generator fails in flight, Both Galley 1st then Both Utility Busses (utility off lights will be on), Other things will be loadshed- this is Boeing doing it
53
Load Shedding Priority
Galley Buses
| Utility Buses
54
Overload Load Shed
Galley Buses
| C2 PUMP
55
When STATUS message pops up how do I see it?
Press STATUS page
| to toggle through them, press STATUS again
56
When using performance charts in regards to brake temps
Use BRAKE COOLING CHART
Must Know: Use 2 Engine Reverse Chart
Must Know: If RTO- Use no reverse chart
57
Boeing is trying to save me and my career by?...
```
Flight Control Protections:
Aileron Lockout
Rudder Ratio Changer
Elevator Feels Unit
*Can always overcome a jam in any of these axis
```
58
On Power Up what will ALWAYS happen
Lower EICAS will show up as Secondary Engine Instruments Always
59
What is the controlling perimeter in Normal for the EEC?
| The Non Normal?
Normal: N1
| Non Normal: N1
60
Explain EEC Overspeed Protection:
If you lose control of the engine – will have Protection of RPM in Normal mode. The EEC will take fuel away from fuel metering unit to make sure you don’t hit 117.6 on the red tick.
61
What Main Bus Powers the Ground Service Bus?
Right Main AC Bus
62
If you have a single power source what are you required to do?
Land at nearest suitable airport
63
What does EEC do for me in my normal flying?
Bleed Compensation
Atmospheric Compensation- Change in altitude, EEC
Auto Relight- EEC sense engine going below idle N2 rpm and will relight
Approach Idle- Need this to go from auto thrust to go around thrust
64
When will I go to Approach Idle
1. Landing Flaps
2. Engine Anti Ice On
3. Continuous Ignition
65
Tell me how to slats and flaps move per each position
1- Slats ONLY- MID position
5- Leading Edge Flaps Stay Mid and TE go to 5 (Aileron Droop starts here through 15 to give more roll control at takeoff flaps)
15- LE SLATS MID- TE Flaps 15 (Aileron droop still)
20- LE SLATS MID-TE Flaps 20 (Aileron droop still)- arms load relief
25- LE SLATS FULL- TE Flaps 25 (Still have load relief) Don’t have aileron droop any longer
30- LE SLTS FULL- TE FLAPS 30
Load Relief
* flap load relief will be back to flaps 20 and the handle won’t move
66
How many controllers does each pack have?
2- auto and standby
67
Target Temperature by the PACKS
Lowest of the Four Zones
65 degrees to 85 degrees (selectable range)
Celcius 18 degrees to 30 degrees
68
Master Trim Air Systems
Mixes with the zones that are requesting higher temp than the coldest to warm it up to what is requested.
69
Where does cold air come from for E&E compartment?
Pack Air
70
What part of the air that reaches the cabin is coming from the recirc fans?
Over 50%
71
What is the flow of air to get the air to the zones cooler or warmer?
Air comes off engine- Cooled by the Air Cooler
72
What does Recirc Fan DO?
Left & Right or (Fwd & Aft on overhead)
just takes already conditioned air that is the temp we want it from the cabin and allows it to be filtered and pushed into the common manifold and back to the 4 zones. Allows the packs to work less hard
73
Inop Light on one Recirc Fan?
- On side PACK goes to high flow
| - Fuel burn increases by 0.3% per pack
74
When are the PACKS in high flow?
When they are not in normal flow
| -They are now using 0.3% per pack fuel increase
75
```
Left Pack (fwd recirc fan) Right Pack (aft recirc fan)
What would make the pack go to high flow?
```
Both Engines Must be running for this logic to remain true.
1. If one PACK has a fault the other PACK will go to high flow.
2. If I lose the recirc fan, it's partner PACK will go to high flow.
76
If I have a single engine shutdown and a single PACK failure...
That working pack will be inhibited from going to high flow because we don't want to work it too hard and make it fail to keep pressurization working.
77
Tell me about the Air flow to adjust temperature in the cabin process.
Air comes through pack valves, is tapped off to Heat Exchanger and sent to trim air valve. Next moves to Air Cycle machine.
78
Master Trim Air Switch will de-power every zone control valve?
Yes,
79
What could bring on the four inop lights for each cabin zone?
1. Me Turning off master trim air switch
| 2. Fault in master trim air system
80
What if I have a single inop light for a zone?
1. Fault with individual control valve
| 2. I've taken the controller and moved it to off from AUTO
81
What bus are recirculation fans powered by?
Utility Bus
82
If I don't have utility busses what would happen to my packs if both engines are running?
They both go to high flow
Work harder and last for less time.
.3 + .3 =.6% fuel flow increase
83
Pack Reset Light- WHAT DO THESE LIGHTS MEAN?
PACK OFF:
INOP:
Both?:
PACK OFF: Can come on by itself- Pack valve closed.
INOP:
1. Pack overheated or fault in automatic control system- not putting out what I wanted. Commanded 71 degrees and its giving you 72 degrees.
2. Could Also be PACK control Fault. (we have 2 controllers)
SELECT STBY N- If condition extinguishes: Controller Issue- Pack will now output 75 degree
- get checklist out-
Both: Internal overheat
Auto Shuts Pack Off
After cools -you can do 1 reset
84
Where does Aft & Bulk Cargo Heat come from?
BODY Duct
85
Where does FWD Cargo Heat Come from?
Pneumatic air from CENTER duct
86
Each Cargo Switch Controls 2 Valves, what are they?
```
Shutoff Valve (SOV)
Temperature Control Valve (TCV)
```
87
Selecting Cargo Heat switches does what to each compartment?
What temp does it warm to?
1. Overtemp valve to fully OPEN
2. Control valve to operate automatically from Boeing logic
(Air coming out of center or body duct warms to 45 degree F)
88
What does the Cargo Heat OVHT valve do?
Acts as a backup-Sits there like a police officer waiting for Control valve (that hangs around 45 degrees) to fail. ONce fails, says I will let the temp go all the way up to 90 and then close Temperature in cargo area goes for 90, 89, 88, 87. The dog will still be alive but not happy!
89
Bulk Cargo Area selecting VENT does what?
Live animals are carried in Bulk Cargo
Normal allows 45 degree temp to be contained
VENT will keep bulk cargo temperature 65 degrees for the dogs!
Does this by me moving selector to VENT- activating fan and opening up a valve to take air out of cabin to the bulk cargo area
90
What systems are part of pressurization system?
Main Gear Air Ground Logic
| Air Data Computer
91
When do you pressurize?
Thrust levers put into the takeoff range
(this moves outflow valve closed during takeoff)
Captains Altimeter
92
What part does the FMC play in pressurization of your airplane?
No part in pressurization
93
How many controllers are part of the pressurization system?
3 (2 AC, 1 DC) It's on the knob
Auto 1- AC Powered Automatic Control
Auto 2-AC Powered Automatic Control
MAN- DC motor that lets me control the cabin manually
94
What is crew required to do with the Pressurization Controller?
1. Set Landing Field Elevation
2. Select Auto 1 or Auto 2 (whoever is flying CA or FO)
3. Verify AUTO RATE is in index position (climb 500fpm descent 300 fpm)
95
Land after 8 hour flight, what is target cabin altitude to select?
200' lower than the elevation of where you are landing. But never to exceed .125 inches if differential pressure
96
When I land what does main gear logic do?
Allows the outflow valve to go wide open to depressurize.
97
200' equals what?
.125 PSI
98
How does the cabin climb?
Relative to the airplane climb.
99
Airplane Logic of Climb Cruise Descent
Climb, Cruise, Descent
Level off in 1 minute Climb will change to Cruise-
1000' dictates climb back to cruise
Boeing has programmed into pressurization system to look at final cruise altitude and cabin altitude you're at and you're landing altitude. Will take the higher of the two to calculate new PSI differential.
I.e. Denver example from class
100
Target of this pressurization system FL35 or greater should be what?
8.6 PSI
(if it is higher- tell Captain- maybe outflow valve stuck or not working properly)
The system will do it's best to maintain 8.6 all the way up to Flight Level 350 and higher
101
Max Differential Pressure where Overpressure Relief Valve is starting to kick in is ___ PSI. Doors will open up and let pressure decrease to a safe PSI.
9.1 PSI
102
Coming into Denver, I put in my arrival- Last altitude on arrival is 4000'. Power off descent all the way down the STAR. What does the controller do?
More than 1000' fpm CRUISE mode changes to DESCENT mode
| Goal is to have cabin altitude stop 200' below LFE .125
103
Flying in AUTO 1- lose AUTO 1, what happens?
AUTO 1 will automatically switch to AUTO 2
104
What if I move Mode Select to Auto 1 to Manual with everything powered normally?
Nothing will happen to outflow valve it'll freeze and it will just show AUTO INOP light above the knob. Same as if there is a failure- the outflow valve will stop and not move!
105
When would you see AUTO INOP light on Mode Select Panel
AC failure of AUTO 1 or AUTO 2
| Moving the controller to MAN
106
How many negative Pressure Relief Valves?
| Where are they?
5 Negative Pressure Relief Valves
1 on left side of airplane forward of positive pressure relief doors AIRCRAFT LEFT
2 on fwd cargo door AIRCRAFT RIGHT
2 on aft cargo door AIRCRAFT RIGHT
107
Over Pressure Relief Valves
2 Forward of left wing root
108
CABIN ALT light comes on when?
10000'
Warning system is our ears!
PUT YOUR MASK ON and call for Immediate Action Item Checklist
"CABIN ALT"
"RAPID DECOMPRESSION"
I need to tell ATC "i'm losing my cabin, I need to descend what heading do you want me on to avoid traffic."
109
Cabin altitude continues to climb and reaches 11,000' what happens? What is it called?
CABIN RATE LIMITING!
Separate signal sent to outflow valve by DC power to command it CLOSED.
“If you reach 11000 feet with DC power closing the outflow valve it is called Cabin Rate Limiting”
110
Cabin Altitude reaches 14,000' what happens?
Rubber Jungle Deployment Automatically (12 mins supply)
111
Once cabin goes back below 8,500' what happens?
Warning resets in case it re climbs above 10,000'
