Electrics Flashcards
What does the commercial pb control?
- Cabin and cargo lights
- Water and toilet system
- Drain mast ice protection
- Galleys
What does the GEN 1 LINE pb do?
Isolates GEN 1 from AC BUS 1
The number 1 fuel pumps in both inner tanks are now connected directly to GEN 1 (normally to AC BUS 1) to avoid gravity fuel feeding
When are the main galleys shed?
When only one generator is operating in flight
(or on the ground when the aircraft is being supplied by 1 engine generator only)
After the loss of AC BUS 1 and 2, how long does it take for RAT extension and emergency generator coupling?
8 seconds
What restrictions are there on the operation of the red guarded IDG pb?
Do not press for more than 3 seconds as it may damage the disconnect mechanism. The IDG should only be disconnected on a running or windmilling engine.
What systems are lost with an AC BUS 2 FAULT?
FO PFD, ND and SD (Lower DU)
MCDU 2
Reverser 2
Y ELEC Pump
RA 2
And loads more!
What systems are lost with an AC BUS 1 FAULT?
Reverser 1
RA 1
BLUE ELEC Pump (And thus B sys)
And loads more!
What systems are lost with an AC ESS BUS FAULT?
CPT PFD, ND and E/WD (Upper DU)
MCDU 1
Pax Oxygen Masks
APU Fuel Pump
And loads more!
What systems are lost with a DC ESS BUS FAULT?
BLUE ELEC Pump (And thus B sys)
ACP 1+2
A/THR
VHF 1
AP1
HP Fuel Shutoff Valves
Even if the ECAM Status page displays CAT 3 SINGLE ONLY, the real landing capability of the aircraft is CAT 2, due to the inoperative A/THR Once the approach mode is armed, the FMA displays the correct landing capability CAT 2.
Which screens are lost in EMER ELEC?
FO PFD, ND and SD (Lower DU)
Same as AC BUS 2 FAULT
Look at QRH ELEC EMER CONFIG SYS REMAINING
What is the reconfiguration of the electrical system in a double TR fault?
The ESS TR powers the DC ESS BUS from the AC ESS BUS. As both TRs are lost; DC BUS 1, DC BUS 2, and the DC BAT BUS are lost.
What is the reconfiguration of the electrical system in a single TR fault?
The ESS TR automatically replaces the faulty one through the AC ESS BUS, and powers the DC ESS BUS. DC BUS 2 powers the DC BAT BUS and DC BUS 1 (in a TR1 fault)
What is the configuration of the electrical system in emergency electrical configuration in flight?
The EMER GEN (RAT, blue hydraulic system) supplies the AC ESS BUS, and the ESS TR. This supplies the DC ESS BUS.
What is the configuration of the electrical system in emergency electrical configuration if the RAT stalls or on the ground below 100 kts?
The EMER GEN has nothing to drive it. The batteries supply the electrical system via the static inverter. AC SHED ESS BUS and DC SHED ESS BUS are lost.
What happens below 50 kts on the ground in the emergency electrical configuration?
The AC ESS BUS is automatically shed, leading to the loss of all DUs.
In normal electrical system config, which side has a higher load?
IDG1 has approx 10% higher load as:
- AC 1 powers AC ESS
- DC 1 powers DC BAT which powers DC ESS
What is the Bus Tie?
The bus tie allows power to be transferred between each side of the electrical system.
It allows the APU Gen to power both sides.
What happens in time between AC bus failure and Emergency generator taking over?
Takes 8 secs for Emer Gen to come online.
In mean time:
Battery 1 powers AC ESS through Static Invertor
Battery 2 powers DC ESS
QRH ELEC procedures?
ELEC EMER CONFIG Summary
ELEC EMER CONFIG Sys Remaining
C/B TRIPPED
3 occasions batteries connect to BAT bus?
APU battery start
Flight on batteries only
Recharge cycle
3 types of CB?
Monitored - green (ECAM after 1 min)
Unmonitored - black
Cannot be reset - red sleeved (WTB)
What is the reconfiguration of the electrical system in an AC Bus 1 fail?
AC ESS bus is powered by AC 2 via the AC Essential Feed (automatic)
AC ESS powers DC ESS through ESS TR
DC 2 powers DC1 through DC BAT Bus (5 second delay)
{How to remember - DC BAT bus can only power one other bus so can’t power DC 1 AND DC ESS - ESS TR comes online}
Consequences of a TR 1+2 failure?
Lose DC 1, DC 2 and DC BAT.
{ESS TR can only power DC ESS}
What is the difference between EMER ELEC CONFIG and SMOKE CONFIG?
Initiated by pilots to isolate smoke causing electrical equipment.
1 fuel pump stays on in each inner tank so gravity feed not required
Expected to return electrics to working condition before landing (reversible) - restores reversers, normal brakes, NWS, screens etc
How can you look up what will power what in the event of various electrical failures?
FCOM Distribution Table (Bookmarked in Docunet)
When does the RAT automatically deploy?
AC BUS 1 and AC BUS 2 lost and aircraft speed >100kt
In the event of RAT stalling or aircraft on ground and <100kts, what powers what electrically?
HOT BUS 1 powers AC ESS via STATIC INV
HOT BUS 2 powers DC ESS
AC SHED ESS and DC SHED ESS are shed
When on ground and <100 kts, DC BAT BUS connects to batteries
When on ground and <50kts, AC ESS BUS shed leading to loss of all DUs
Describe the battery check during Prelim Cockpit Preparation
If batteries not been powered for >6h:
- With batteries off, check >25.5V
- This ensures charge >50% & is min for APU Test & start. If do APU Test when <25.5v, could discharge fire ext. bottle
- If below 25.5V, switch to AUTO & EXT PWR on. Charge for 20 mins then recheck.
Describe the battery check during Cockpit Preparation
- BAT 1 and BAT 2 pb OFF then ON
- Initiates charging cycle
- Check 10 sec after pb ON that current is <60A and decreasing
- If not, wait until charging complete and then recheck
Actions and consequences of a tripped CB
QRH CB Tripped
Basically says if on ground call Maintrol. Never reset fuel pump CB. If in flight, don’t reset unless you have to and only reset once.
If a monitored CB trips and press CLR, all CBs on that panel now unmonitored unless reset the CB.
If a monitored CB trips and use EMER CANC, all CBs unmonitored.
Why do you reset the generators on approach in SMOKE config?
Restores reversers, normal brakes, NWS, screens etc
May still land in ALTN/DIRECT LAW due IR 2 and IR 3 being unpowered in SMOKE config.
Note at end of ELEC EMER CONFIG SYS REMAINING table says can keep IR3 powered with ATT-HDG Selector switching which may lead to retaining NORMAL LAW.
This would reduce landing distance required (DIRECT LAW landing - CONF 3 only and VREF + 10/15 kt (depending on A/C type)
How much flight time when on batteries only?
> 30 mins
