Electrical Sys Flashcards
Review
After eng start …. starter gens supply electrical power
4
There are…Ext pwr connections for grd use only
3
Electrical Pwr can also be supplied by…Starter Gens
2 APU S/G
Apu Star/Gen are a backup source in flight is
1 or more Str/gen are inpo
If all elec gens malfunction what will deploy?
RAT
The Rat is the ….
Primary Stby Pwr source
Is there limits to the RAT operations?
No
The 787 have …main AC Buses, which supply power to all the airplane loads
4 AC Buses (L1/2 R1/2)
The 4 AC Buses are connected by left and right..
Bus ties: Which Close automatically to keep the main buses energized, if a Str/Gen becomes inop.
Tie bus do what?
Connect the main buses
Let Apu energize main buses
White boxes on the elec synoptic tells you
Generator is de-energized
When battery stw is push which lights come on for the electrical panel?
4 str/gen off & drive lights ( L1/2 R1/2)
If external is not connected to the airplane, only …. CCR (common computing Resource) is energized. Which take … … to come online?
Left
…
almost 1 min
CCR when start up …
start a number of programs that monitor and control th airplane systems
When the CDU shows on the lower display unit, it means..
The left CCR is online
Can you start the Apu before CCR is online ?
No
CCR must be online for 35 secs min
If external is connected to the airplane, the Left and Right CCR (common computing Resource) will energized. How long will it take to come to come online?
approximately 3 mins
Although Left & Right Forward Ext Power are on the same same time. Some airplane systems are…
Load Shed until more power is available
Items load shed are shown…
On elec synoptic, under load shed
Avail light on the EXT Pwr Stw tells you external pwr is?
And it is shown on the synoptic as
Connected and good quality
….
Green box
Fwd ext Pwr can automatically energize…. when an AVAIL light comes on. And the 1st Ext Pwr source that is connected supplies….
Grd handing Loads
…
Power through the main AC buses
The ON light for the Ext Pwr, tells you?
The synoptic now shows a …. through the external power boxes
Pwr is connected to the electrical systems.
….
Green line
With only 2 External pwr sources (Fwd Ext Left & Right).. What is also loadshead
Air- Cabin air compressors
The Aft Ext Pwr is used only for …& ….. It cannot be used to supply pwr to the …..
Engine Starts & Maintenance Grd ops
….
Main buses
Aft Ext Pwr connects to large motor power sources like?
Hyd pumps
Cabin Air compressors
Right Eng Start/ Generators
When you start engine with ext power only. It’s better to use …External Pwr sources.
3
…
Usually fwd ext pwr is connected….. the connection of the aft ext pwr.
Before
If only Ext Pwr is available, and bcuz Aft Ext can only energized for Rt eng start. Start …Eng first, then cross start procedure for Starting left eng.
Right eng-> minimize load sheading