CARAVAN FLTSFT MAN Flashcards
what is the electrical system of the caravan ?
28 Volts DC
page 2-1
what are the Volts of the Lead Acid Battery ?
24 Volts
page 2-1
what supplies primary power to the electrical system once the engine has started ?
the starter generator
page 2-1
is additional power available to the electrical system ?
yes
page 2-1
what are the TWO additional power sources to the electrical system ?
EPU
STBY ALT
page 2-1
to which buses is the DC power routed to ?
- power distribution bus
- battery bus
- general bus (x2)
- avionics bus (x2)
- standby alternator bus
page 2-1
what is the particularity of the Battery Bus ?
it is a Hot Bus which mean it energises continuously for cabin/courtesy lights and other functions requiring power when the two general buses are off
page 2-3
where is the battery located ?
on the right forward side of the firewall on a swing-out tray
page 2-3
does the battery have also the role of absorbing voltage spikes ?
yes
page2-3
why is the battery case ventilated ?
to prevent a concentrated accumulation of hydrogen within the airframe
page 2-3
What is the other role of the battery overboard vent ?
to drain any acid condensation produce during system charging
page 2-3
where is the Generator Control Unit located ?
on the left forward fuselage sidewall
page 2-4
what does the GCU do ?
provides the electrical control functions of the starter-generator
page 2-4
at what Ng percentage does the GCU automatically cuts off the starter ?
46%
page 2-4
once the Ng have reached above 46% what happens to the starter-generator ?
it functions as a generator an no longer as a starter once the Starter Switch is position to OFF
page 2-4
where is the starter-generator position ?
12 o’clock position on the accessory gear box (AGB)
page 2-4
what runs the starter-generator ?
is driven by the engine through a splined shaft
page 2-4
what are the Volt and Amps of the Generator ?
28 Volts 200Amps (300Amps optional)
page 2-4
describe the cooling system for the starter-generator ?
an integral fan and blast tube above the oil cooler in the air inlet on the right forward cooling cools the starter-generator
page 2-4
does the GCU have an overspeed sensor ?
yes
page 2-4
does the GCU have an automatic starter shut off ?
yes
page 2-4
what prevents an external power to battery connection during engine start ?
the external power control circuit
page 2-4
what else does the ground service circuit protect the aircraft electrical system from ?
- polarity reversal: if the plug is plugged the wrong way
- overvoltage protection
page 2-5
what is the role of the ground power monitor ?
to close the external power contactor when the applied voltage is within the proper limits
page 2-5
describe the components of the Standby Electrical Power System ?
- 75 Amps Alternator (belt driven from the accessory pad)
- ACU
- Standby Alternator Contactor
- Two Switches: Avionics STBY PWR, Avionics BUS TIE
page 2-5
When the EPU switch is OFF….?
external power goes to the ground power unit only
page 2-5
When the EPU switch is on STARTER…?
- external power goes to the starter circuit only
(battery power is applied to the main bus) - no generator power is available
page 2-5
When the EPU switch is on BUS…?
- the external power goes to the power distribution bus
- no power to the starter
page 2-5
how do you connect the battery to the power distribution bus and external power ?
Battery Switch to ON
page 2-5
when the Battery switch is ON….?
battery power is supplied to the 2 general buses
page 2-6
when the Battery switch is OFF…?
power is deactivated to all the buses except the battery bus (HOT BUS)
page 2-6
describe the three position of the spring loaded Generator Switch ?
RESET, ON, TRIP
page 2-6
describe the IGNITION Switch ?
ON: the igniters will ignite constantly
NORM: the igniters will ignite when the STARTER switch is on START
page 2-6
describe the STARTER Switch ?
- OFF: deenergizes the ignition system
- START: energises the ignition system when on NORMAL, once the engine is self sustaining it must be position to OFF
- MOTOR: motors the engine without the ignition system energising
page 2-6
is the STARTER switch spring loaded ?
only when selected to the motoring position. once release it will spring load to OFF
page 2-6
what does the inter-lock between the MOTOR position of the STARTER switch and the IGNITION switch does ?
it prevents the starter from starter from motoring unless the IGNITION switch is positioned to NORM
page 2-6
what does the Avionics BUS TIE switch do ?
connect the No1 and No2 avionics buses if either bus feeder circuit fails
page 2-6
how long should a circuit breaker cool before being reset ?
3 min
page 2-7
when does the VOLTAGE LOW CAS (crew alerting system) comes on?
when the battery is at 24.5 Volts and is supplying power
page 2-7
when does the VOLTAGE HIGH CAS comes on ?
when the bus voltage is greater than 32 Volts
page 2-7
in what situation will the generator automatically disconnect from the buses ?
under high voltage or reverse current
page 2-7
to ensure adequate alternator cooling, what is the procedure when operating above 21000feet ?
reduce the max load by 5amps per 1000ft above 21000ft
page 2-8
what is the STBY PWR circuit breaker amps limit ?
40amps
page 2-8
after a start at what Ng percentage should the STARTER switch go on OFF ?
52%
page 2-10
to what voltages does the electrical system have to drop for the STBY ELCT PWR to automatically kick in ?
27.5 Volts
page 2-10
detail all the components of the fuel system ?
- 2 vented integral fuel tanks with shut off valves
- a fuel-selector-off warning system
- a fuel reservoir
- an ejector fuel pump
- an electric auxiliary boost pump
- reservoir manifold assembly
- a firewall shut off valve
- a fuel filter
- an oil to fuel heater
- engine driven fuel pump
- a fuel control unit
- a flow divider
- dual manifolds
- 14 fuel nozzle assembly
page 5-1
does fuel flow form the tanks to the fuel system by gravity ?
yes
page 5-3
what is the purpose of maintaining fuel around the ejector pump and the boost pump in the reservoir ?
to prevent pump cavitation in low fuel quantity situation, especially during in-flight maneuvering
page 5-3
what pumps the reservoir fuel ?
the ejector pump or the electric auxiliary boost pump
page 5-3
where does the reservoir fuel gets pumped to ?
the reservoir manifold assembly
page 5-3
how is the main ejector pump operated ?
is driven by motive fuel flow from the FCU, usually provides fuel fuel during engine operations
page 5-3
what are the advantages and uses of motive fuel flow ?
They are lightweight and relatively simple systems in comparison to using mechanically driven transfer pumps at all the tank interfaces. It is all the same fuel being used for engine feed, and motive flow, but fuel that isn’t being consumed is regularly cycled through the motive flow circuit, and then back into the tanks.
Reference https://www.physicsforums.com/threads/what-is-motive-flow-in-an-aircraft-fuel-system.470818/
if the main ejector pump fails what does come on automatically ?
the electric fuel boost pump
page 5-3
which fuel fuel pump supplies fuel flow during starting ?
boost pump
page 5-3
the extension of the red filter bypass flag is an indication of what ?
the fuel filter has become blocked with foreign materials and the filter has started bypassing fuel
page 5-3
fuel from the filter is routed through the oil-to-fuel heater to the engine-driven fuel pump, after this where does the fuel go ?
to the FCU
page 5-3
what is the role of the FCU ?
meters the fuel and directs it to the flow divider (which distributes the fuel to the dual manifolds and 14 nozzles in the combustion chamber)
page 5-3
where does the fuel rejected from shut down goes to ?
into a fireproof fuel can on the front left side of the firewall
page 5-3
the boost pump operates when the fuel pressure drops below…?
4.75psi
page 5-4
when the FUEL BOOST switch is on NORM…?
the pump is armed and operates when fuel pressure in the fuel manifold assembly drops below 4.75 psi
page 5-5
when the FUEL BOOST switch is ON…?
the boost pump operates continuously.
the ON position is used for engine start
page 5-5
can the fuel filter red bypass flag be reset by the pilot ?
no, an engineer must be called
page 5-5
where is the fuel flow measured ?
downstream of the FCU before the fuel is routed to the flow divider
page 5-5
when the indicator shows an empty tank, how many gallons of unusable fuel are left ?
2.5 gallons
page 5-6
when the RSVR FUEL LOW appears the fuel level in the reservoir has dropped to approximately ?
one-half full
page 5-6
how many second of engine operation do you have when the RSVR FUEL LOW appears with engine at maximum continuous power ?
90 sec
page 5-6
how many minutes of engine operation do you have when the RSVR FUEL LOW appears with engine at reduce power ?
3 min
page 5-6
when the L or R FUEL LOW appears what is the max amount fuel it will be in the tanks ?
25 gallons decreasing
page 5-6
with the Fuel Tank Selectors both to OFF, is it possible to start, taxi and take off before the reservoir tank fuel is exhausted ?
yes
page 5-7
what should be considered before starting to refuel especially in an uneven area?
turn off at least one fuel tank selector to avoid involuntary cross-feeding and fuel unbalance
page 5-7
what is the maximum fuel imbalance ?
200 pounds
page 5-9
if you have a red RSVR FUEL LOW what should you do?
- position fuel tank selectors BOTH ON
- ignition switch ON
- fuel boost pump ON
page 5-9
what are the only two items that are not part of the AGB ?
- propeller tachometer-generator
- propeller governors
page 7-1
how are the engine accessories driven ?
by the compressor turbine with a coupling shaft that extends the drive to a conical tube in the oil tank centre section
page 7-1
what is the capacity of the oil tank ?
9 US quarts
page 7-1
what is the capacity of the entire oil system including tank, engine sumps, lines and filter ?
14 US quarts
page 7-1
what is the function of the planetary reduction gearbox ?
reduces high rpm/low torque of the engine in low rpm/high torque required by the propeller
page 7-2
what are other functions of the reduction gearbox ?
- drives the propeller tachometer
- drives the propeller governor
page 7-2
what gives the indication of power delivered to the propeller ?
a torquemeter in the reduction gearbox
page 7-2
where does the power turbine shaft extends to ?
forward to drive the reduction gear
page 7-2
where does the gas generator turbine shaft extends to ?
behind to drive the compressor and the accessory gear box
page 7-2
the composition of the engine compressor ?
one compressor turbine connected to one centrifugal wheel and 3 axial compressors
page 7-2
where should the oil be maintained to ?
1.5 quarts MAX HOT or MAX COLD
page 7-5
what is the right procedure to have a correct reading of oil quantity ?
- within the 10 min from engine shut down while oil still hot (MAX HOT)
- or first flight of the day (MAX COLD)
page 7-6
how many igniters does the engine have and where are they located ?
2 igniters, located in combustion chamber
page 7-6
what ignites the igniters ?
the ignition exciter
page 7-6
when should a pilot select the ignition switch ON ?
- airstart without starter assist
- operation on water covered runways
- flight during heavy precipitations
- inadverted icing encounter after bypass on for 5 min
- operations using the emergency power lever
- near fuel exhaustion
page 7-6
what does the FCU includes ?
- fuel metering section
- temperature-compensating section
- gas generator pneumatic governor
page 7-8
in what occasion does the power level also work as a propeller pitch lever ?
when the power lever is retarded below IDLE to the BETA or REVERSE range it overrides the propeller pitch lever
page 7-14
if the FCU pneumatic decreases the fuel flow to minimum idles what Ng percentage will the pilot read ?
approximately 48%
page 7-15
what is the use of the EMERGENCY PWR LEVER ?
to restore power in case of failure of the FCU where fuel flow goes to minimum and as a consequence Ng goes to 48%
page 7-15
Fuel Condition Lever Settings ?
CUT OFF: off
LOW IDLE: provide rpm of 52%Ng
HIGH IDLE: provide rpm of 65%Ng
page 7-16
describe the HEAT SENSOR fire system ?
consist of one flexible closed loop. when the engine compartment temperature becomes excessively high, the heat changes the resistance of the closed loop, which is sensed by a control box on the aft side of the sidewall.
page 8-2
fire warning is initiated when temperature in the engine compartments exceed what ?
218ºC on the firewall (first section)
329ºC around the exhaust (second section)
323ºC on the rear engine (third section)
page 8-2
