Electrics/Fire/Warnings Flashcards
What does each AC power system consist of? (4)
- XFR BUS
- Main Bus
- 2 Galley Buses
- Ground Service Bus
What power do the AC generators supply?
3 phase 115V 400Hz AC power.
Why will an IDG automatically disconnect?
High oil temperature.
Can also be disconnected manually in the cockpit.
Why will SOURCE OFF illuminate inflight?
When respective XFR BUS is powered through BTB system.
What is overload protection of the AC system?
Incrementally sheds loads when on single IDG.
In what order is AC load shed?
First galley and main bus power on XFR BUS 2. Then XFR BUS 1. If continues, next is the IFE.
Will auto restore if another GEN comes online.
What will automatically be load shed inflight if APU GEN sole source?
All Galley and Main Buses, if still overloaded, IFE.
Where can APU attempt a full electric load?
On ground.
When will the DC Cross Tie Relay open during normal operations? (2)
- When GS captured by either AP or FD.
- BUS XFR switch to OFF
What switch will OPEN DC Cross Tie Relay?
Bus XFR switch in OFF position. (Normally in AUTO)
When is TRANSFER BUS OFF illuminated?
When respective XFR BUS not powered.
When will STANDBY POWER OFF illuminate? (3)
Loss of power to either AC Standby Bus, DC Standby Bus or Battery Bus.
What does the Standby Power switch in AUTO allow?
Allows automatic transfer of power to standby buses whether aircraft inflight or on ground.
What is the AC Standby Bus powered by in normal conditions?
Transfer Bus 1
What is the DC Standby Bus powered by in normal operations?
TR1+2, using TR3 as a backup.
In case of AC power failure, what is the AC Standby Bus powered by?
Inverter from the battery. Same as DC STBY BUS.
What does the battery remove power from when placed to off?
BATT BUS and Switched HOT BATT BUS when operating normally.
What does BATT switch on power?
Switched Hot Battery Bus, and energises relays to provide automatic switching of standby electrical system when normal power fails.
When may the BATT DISCHARGE light illuminate in normal operations?
APU Start
What does the TR UNIT light illuminate for?
Whenever a TR unit fails on the ground. Inflight, monitors TR1 and a combined TR2+3 failure.
What causes the ELEC light to illuminate?
On ground whenever there’s a DC Power System fault or Standby System fault. Inhibited inflight.
What will the DRIVE light illuminate for?
Low IDG oil pressure.
When will the DRIVE light illuminate? (3)
- Engine fail
- IDG Fail
- IDG disconnect
When are the IDG disconnect switches operational? (2)
Electrical power available and engine running.
When will the automatic engine generator online function work? (3)
- APU power fails
- APU turned off
- Switch to IDG on takeoff
Where is the DC power usually powered from?
28V DC from the TR’s.
No direct control over DC system.
What is powered by TR1?
DC BUS 1 and DC STBY BUS. Can be all 3 TR’s if cross tie relay closed.
What can be powered by all TR’s of cross tie relay closed?
DC BUS 1, DC STBY BUS and DC BUS 2.
What TR is BATT BUS powered by?
TR3, with an alternate source from the battery charger/battery.
How can the standby system be powered when the BATT switch off?
Standby power switch must be placed to battery to power standby system from battery.
How many TR’s are capable to supply total connected load?
2
What the main and aux batteries, and how long will they last?
24V NiCad batteries. Provide standby power for minimum 60 minutes.
What indicates if engine overheat detected, or APU DET INOP?
Master Caution
What will fault monitoring fire system do if it senses a fault?
Deselect bad loop. Then only selected loop (A or B) can activate warning.
What does overheat FAULT light indicate?
Both loops are malfunctioning.
What happens when the APU fire switch is pulled up? (3)
- Arms squibs
- Close APU Fuel SOV
- Trips generator field and generator breaker.
Is there a fault warning for wheel well fire detector?
No. Detector only checked by use of OVHT/FIRE TEST switch.
Nose wheel well has no fire detection capability.
Where is the APU ground control panel?
Right aft main wheel well.
What happens if ground control APU fire handle pulled down? (4)
- APU Fuel SOV
- Bleed air closes
- Inlet closed
- Trips APU GEN & Generator breaker.
Is there a light to show APU bottle has been discharged?
No. Only discharged from cockpit.
When testing OVHT/DET, what do you need to ensure?
Both switches in normal, and all fire system lights are out.
What does FAULT/INOP switch illuminate? (4)
- MASTER CAUTION
- OVHT/DET
- FAULT
- APU DET INOP
What power will cause wheel well fire light to not illuminate?
Only on DC power.
How many extinguisher discharge circuits for engines and APU?
- 2 for engine
- 1 for APU
What smoke detection installation is used in the cargo compartments?
Dual loop detectors. Single loop available if one fails.
What is the power source for cargo compartment smoke detection?
Power source is DC BUS 1 and DC BUS 2.
What illumination do you get if smoke detected in cargo compartment?
FIRE WARNING & FWD/AFT CARGO FIRE light.
What illumination will you get with a DETECTOR FAULT light?
MASTER CAUTION and OVHT/DET
When will DISCH light illuminate?
Once cargo compartment fire light has been armed.
How long does cargo compartment discharge take?
30 seconds. Amber DISCH light may not illuminate for up to 30 seconds.
Second bottle discharges after 60 minutes.
How long is the fire suppression in the hold?
75 minutes.
What does proximity switch electronic unit (PSEU) monitor? (3)
- TO Config
- Landing gear config
- Landing gear
- Air/Ground sensor warnings.
When is MAINT light inhibited?
From first engine start until 30 seconds after landing.
What triggers TO Config horn? (5)
- TE flaps not in F1 - F25 range
- TE flaps in skew or asymmetry, or uncommanded motion.
- Speedbrake lever not down.
- Spoiler control valve is open providing pressurised hydraulic fluid to ground spoiler interlock valve.
- Parking brake set.
- Stab. Trim not in green band.
When will red gear light illuminate because the gear is not down?
Below 800ft AAL and either/both thrust lever at idle.
When can use landing gear horn cutout inflight?
Above 200’RA. Located behind start levers.
When will landing gear horn operate?
Below 800’ RA with both engines running when either lever between idle and 20 degrees.
If OEI, sound if operating engine idle to 34 degrees.
(FLAPS UP to FLAPS 10)
When can’t the landing gear horn be silenced? (3)
- Below 200’ RA
- When gear not down and flaps F15 to F25.
- Flaps 25+, will sound regardless of levers.
When will landing gear horn sound above 200ft regardless of levers?
Gear not down and flaps 25+.
When do GPWS alerts become active?
Below RA activation altitude.
What does Amber GPWS PROX INOP mean? (3)
Either GPWS computer malfunction, power loss or invalid inputs.
When do you get terrain alert on approach?
Gear and/or flaps not in landing configuration.
What are the GPWS inhibit switches? (4)
- Gear
- Flap
- Terrain
- Runway
What cancels BELOW G/S light?
Pushing the switch, below 1000ft RA.
At what AOB do you get bank angle warning?
35 degrees AOB.
Silent until reduced below 30 degrees.
What is the enhanced bank angle warning?
Provides red arrows back to S+L when bank exceeds 45 degrees.
Below which altitude will you get WINDSHEAR red message and aural warning?
1500ft.
On takeoff, begins at rotation.
When is terrain clearance floor active?
When close to airport with EGPWS.
How long before terrain impact will give look-ahead caution alerts?
40-60 seconds from impact. Repeated every 7 seconds.
What will you be presented with prior to a terrain caution with EGPWS?
Density dot pattern of terrain.
How long before terrain impact will you get a warning alert?
20-30 seconds. Warning is continuous.
What altitude is RAAS armed?
500ft above TDZ elevation.
When is on-ground overrun armed?
3 seconds after touchdown, to below 20 knots ground speed, or within 1000ft of runway end.
When do you get speed brake not up alert?
Above 80 knots on landing.
What has higher priority, GPWS, TCAS or RAAS?
GPWS, TCAS, RAAS
When will the RUNWAY INOP light illuminate? (3)
- GPS POS U/S
- Not in database
- Inhibit switch
What are the 3 levels of predictive windshear?
Advisory, caution and warning.
When does predictive windshear system operate?
Below 2300ft, but no advisories above 1200ft.
How far ahead of aircraft does PWS operate?
3NM
When are windshear cautions inhibited?
Between 80kts and 400’ RA.
When are windshear warnings inhibited?
Between 100kts and 50’ RA
What windshear alerts will you get between 400 and 50’ RA?
Only warnings.
What are the priority of warning systems?
GPWS, PWS, TCAS
Do windshear advisories have an aural alert?
No. Advisories between 1500’ and 50’.
What does TCAS detect with regards to traffic distance and altitude?
30-40NM, above and below 9999ft.
What time to impact is TA and RA?
TA - 40 seconds
RA - 25 seconds
What distance and altitude is OTHER TRAFFIC on TCAS?
Outside 6nm and 1200ft above or below.
What is proximate traffic?
Within 6nm and 1200ft.
What is the difference between a corrective and preventative RA?
Corrective is change V/S. Preventive is hold V/S.
How long to respond to RA?
5 seconds, with 0.25g of force.
When are RA’s converted to TA’s on approach?
Below 1000’ RA
When is descent and increase descent RA’s inhibited?
Below 1100ft, and 1500ft RA.
What altitude are all TA aural alerts inhibited?
Below 500ft RA.
How quickly should increase correction RA’s be actioned?
Within 2.5 seconds.
Where are each TR’s powered from in the AC system?
TR1 from AC XFR BUS1, TR2 from AC XFR BUS2. TR3 shared between.
What does TR UNIT light indicate INFLIGHT or on GROUND?
Inflight, either TR1 or TR2+3 failure. In ground, any TR failure.
What are the detector loops powered by ?
BATT BUS
What are fire bottles powered by?
HOT BATT BUS
What may be needed for WHEEL WELL illumination?
AC power
How many loops for APU fire detection?
1 (2 for engines)
How many detector loops for cargo hold? Powered by?
2, DC BUS 1+2
How long may CARGO FIRE DISCH light take to illuminate?
30 seconds
