Airframe and Systems Flashcards
What types of flaps are fitted on the PC-12?
Single piece Fowler flap on each wing
What type of linkage do the controls use?
Carbon steel cables and push / pull rods
What type of power is used to operate the aileron, rudder and elevator trim?
Electrical
What’s the aileron/rudder interconnect system?
It is a system that will coordinate the movements of the aileron and the rudder when either of these controls are subjected to an input from the pilot.
What type of ailerons are fitted on the PC12?
Horned ailerons with a balance tab and a rubber seal between the wing and the control surface.
How is pitch trim provided?
By changing the position of the horizontal stabilizier
Where can you verify the position of the trims?
On the MFD (Systems > Trim).
How does the pitch trim operate?
Through an actuator connected to 2 electrical motors. One manual activated by the pilot input and one for the AP which can also serve as a backup trim for the pilot in case of the manual motor failure.
How do you disconnect the trims in case of uncommanded trim operations?
By pressing the TRIM INTR switch located in front of the engine control quadrant on the central console.
What are the different flap settings?
0°, 15°, 30°, 40°
What type of power source is used to extend or retract the flaps?
Electrical
How are the flaps actuated?
Through a Power Drive Unit (PDU) that drives screw shafts at the inboard and middle stations that are connected to the flaps arms by flexible shafts.
What happens in case of flaps failure or asymmetry?
The Flaps Control and Warning Unit (FCWU) will disconnect the PDU and the CAS will display a caution message on the MFD.
What reference does the FCWU use to assess the correct flap position?
It uses the sensor in the flap lever position as a reference. It the cross-checks the data from this sensor with the data received from the other sensors located on the center and inner flap actuating arms.
What happens if the flap breaker pops out?
It can be reset after waiting at least 5 minutes and this reset is limited to two tries maximum.
This is the ONLY breaker that can be reset during flight.
What does an amber cross mean on the trim indication of the MFD?
Invalid trim status
What would happen if the trim is not configured for T-O when on the ground?
The trim aircraft symbol would appear white instead of green and the CAS would show a Take off configuration advisory.
What does an amber cross over the flap position display mean?
Invalid flap position or status.
When will the Flight Alerting System trigger a NO TAKEOFF warning?
When on the ground and you’re not in the take-off configuration or the condition lever is not at flight idle and the engine torque is increased beyond 20 psi with an airspeed < 50 KIAS.
There will be a “NO TAKEOFF” warning displayed on the PFD and an aural “No takeoff” voice will callout.
How is the landing gear operated?
With an electrically driven hydraulic pump.
What happens if you suffer an hydraulic failure while the landing gear is retracted?
A nitrogen filled accumulator maintains the landing gear retracted. If required, the landing gear can be extendend through a combination of free-falling and the emergency landing gear hand pump.
How does the nosewheel steering work?
By mechanical nosewheel steering and differential braking.
How is the landing gear held in the retracted position?
By hydraulic pressure only (no mechanical up-lock whatsoever).
Where’s the hydraulic bay located?
At the root of the left wing.
Where can you visualy inspect the hydraulic fluid level?
During the preflight when the cargo door is open on the side of the wing root.
How is the hydraulic pump powered?
Electrically by the secondary power line.
How is the hydraulic control circuit powered?
Electrically by the essential bus.
In case of failure the power pack, how long is the nitrogen filled accumulator supposed to maintain pressure in the system?
200 min at least.
Is there a ground proximity detection system in the PC-12?
Yes, the Modular Avionics Unit.
What does an amber cross mean on the gear indicator lights?
No data / Unknown status
What does a “Hydraulic Caution” CAS indicator mean?
In flight:
It means that the power pack pump has been operating for atleast 2 minutes
OR
That the main system pressure has fallen below the operational limits (1.800 psi)
On the ground:
It means that the power pack pump has been triggered at least 6 times in 1 hour during flight, which might indicate either an abnormal pressure leak rate or a low hydraulic fluid level.
When will the Flight Alerting System (FAS) sound and display a “Gear” warning?
It will be triggered during flight if the landing gear is not down and locked and at least one of the following conditions are encountered:
1. Speed < 130 KIAS and PCL at idle
2. Flaps are set to 30° or 40°
3. Radar altitude < 200 ft and power setting < 10 psi
In case of hydraulic failure, how do you extend the landing gear?
- Reduce speed to 110 KIAS and move the gear lever down to try extending the gear through gravity.
If landing gear is not fully extended:
- Use the manual gear extension lever to pump until the gear is fully extended down and locked. It takes 60 to 80 strokes to fully extend the landing gear down.
You can also yaw the aircraft to use the aerodynamic load to assist in the extension.
Where does the Modular Avionics Unit (MAU) get the data to feed the air/ground system?
- Main landing gear proximity switches
- Radar altimeter
- Calibrated Air Speed
Which systems is the air/ground signal fed to?
The LH air/ground signal feeds:
- Hydraulics
- Propeller de-ice
- Flaps
- ECS
- LH stick pusher computer
- Flight time counter
The RH air/ground signal feeds:
- RH stick pusher computer
- Weather radar
- Logo lights (when fitted)
What happens in case of air/ground signal failure of the MAU?
If one signal fails and the others are correct, the faulty signal will be detected and disregarded.
If several signals are conflicting, the CAS will display an “Air/Ground Fail” caution.
What happens if both pilots press the brake pedals at the same time?
The one applying the greatest force will control the brakes.
What would happen to the brakes in case of a failure of the aircraft main hydraulic system?
Nothing. The brakes use an independent hydraulic circuit and reservoir.
Where is the brake fluid reservoir located?
On the RH side of the cabin sidewall. It incorporates a fluid level indicator.
How do you set / release the parking brake?
To set the parking brake:
1. Pull the T-handle fully out and rotate it
2. Evenly apply the pedal brakes
3. Release the pedal brakes to finish setting the parking brakes
To release the parking brake:
1. Rotate and push the T-handle fully in
How many fusible plugs are there on the main landing gears and what are they for?
There are 3 fuses on each landing gear that will melt and deflate the tires when the brakes are too hot to avoid bursting the tires.
Where are the life vests in the cockpit?
Under the pilots seats.
What are the dimensions of the passenger door?
1.35 m x 0.6 m
How do you close the cargo door.
It closes almost completely by using an electrical motor, the switch of which is located aft of the cargo door on the outside of the plane.
The motor is connected to the HOT BATTERY BUS and is diconnected by a microswitch operated by the drive mechanism when the door is almost closed.
Once it has reached this position, you then have to finish closing the door manually.
What happens if the Pax or Cargo door is not properly closed?
The CAS will show a Pax / Cargo door warning.
What type of de-icing system is used on the windshield?
It uses electrical resistances embbeded in the wind shield that can raise the temperature up to 60°C.
Once the windshield has reached this temperature, a temperature sensor will automatically deactivate the de-icing system to avoid over-heating.
How many windows are there in the cabin?
5 on the right and 4 on the left.
Where are the emergency exits in the cabin?
The pax door.
The cargo door.
The overwing exit.
How does the PT6 compressor avoid stalls?
By way of a bleed air valve installed on the compressor.
What’s the ITT and where is it measured?
It is the engine Inter Turbine Temperature and is measured between the conmpressor tubine and the two power turbines.
Where’s the oil tank located on the PT6?
Near the accesory gearbox.
How do you prevent icing on the air inlet cowling?
By using the hot exhaust gas to pass through a duct in the cowling.
What is the plenum?
It is an air filter surrounding the conpressor air inlet.
Can you use the inertial separator during take-off?
Yes.
How is the inertial separator activated?
Electrically via an actuator.
When should you use the inertial separator?
In icing conditions or in a Foreign Objects Debris (FOD) environment.
How does the Inertial Separator work for FOD?
It will opne an outlet at the back of the duct, thus increasing the inlet speed flow, accelerating heavy particles that will not be sent to the plenum and instead expelled via the outlet.
How does the inertial separator work in icing conditions?
In icing conditions, the mesh screen that is partly covering the plenum will freeze, thus restricting the flow of solid particles to reach the plenum, further filtering the air.
What’s the main disadvantage of using the inertial separator?
It will overall reduce the airflow sent to the engine, thus reducing the amount of power available.
What should you do in case of a failure of the inertial separator?
Exit icing conditions immediately.
What are the three levers used to control engine power?
From left to right: The MOR, the PCL, the condition lever.
What does the idle detent do on the PCL?
It separates the ground range (aft) from the flight range (foreward).
While forward of the idle detent at low speed, the PCL will directly control the propeller pitch. If the PCL is moved further forward and the aircraft speeds up, the CSU will take control of the propeller pitch.
The beta range (reverse) is part of the ground range.
What’s Ng?
It is the percentage of maximum power of the gas generator (compressor).
What does the MOR do?
It takes over when the pneumatic fuel control system (using bellows) fails.
It mechanically compresses the bellows (Py pressure) located in the Fuel Control Unit (FCU).
What happens in case of a Py leak?
A Py leak will result in a loss of PCL authority.
The engine will then spool down to minimum fuel flow (90 lbs/h) and Ng will drop to 35% Ng on the ground or 70% Ng at 30.000 ft.
The MOR might not be able to deliver max engine power though and when the MOR system is in use, the torque limiter will be inoperalbe.
What are some of the risks of using the MOR?
Using the MOR might result in excessive torque which may damage the engine or in excessive fuel flow which may cause an engine flame out.
When can you use the starter to help recover Ng?
When Ng drops below 50%. The starter won’t engage above 50% Ng.
What is the Fuel Control Unit (FCU)?
It is the system that controls the fuel flow sent to the combustion chamber.
It is connected to the MOR, PCL and condition lever.
It also comprises a return line to manage the amount of fuel sent to the engine.
What is the purpose of the dump valve?
It uses the air held in a purge air accumulator to purge the manifolds of remaining fuel at engine shut down.
The purpose of this purging mechanism is to avoid a hot start on the next engine start-up.
How do you visually inspect the oil level in the oil tank?
By watching the visual gauge on the left side of the engine casing.
The oil level must be in the green range.
What are the magnetic chip detectors and where are they located?
They are magnetic drains that are installed in the oil circuit to detect and filter magnetised contaminant in the oil.
There are two of them in the oil circuit located in the reduction gearbox and in the accessory gearbox.
Where are the oil pressure and temperature sensors located?
On the outbound duct between the oil tank and the different parts of the engine to which the oil will be distributed.
What’s the torquemeter and where is it located?
It is located on the front engine casing.
As torque increases, the oil pressure in the reduction gearbox increases as well.
This pressure will be tranmitted to a series of bellows that will open a bleed valve that will bleed off Py air which will result in a decreased FCU fuel flow causing engine speed and engine torque to decrease.
What’s the limit of the torque limiter and is it effective during take-off?
The torque limit is set to 44.3 psi (AMSL).
The torque limiter will technically be effective during take-off but it remains the responsibility of the pilot to check that the engine parameters are within limits.
What is the torque flat rating?
It is the maximum torque to be applied to the engine given the conditions of the day and the limitations of the airfield.
It should be computed before every take-off by using the performance charts.
Once you engage the starter, under which conditions will it automatically disengage?
After the Ng reaches 50% or 80 sec ON (60 sec for an air start).
How is the electrical power distributed during start-up?
- If ground power is used, it will be providing power for both the essential systems and the starter.
- Otherwise, BAT 2 will provide power to the starter and BAT 1 will be alimenting the essential airplane systems.
- At 10% Ng or 10 sec after activation, BAT 1 will also connect to the starter to boost its capability.
How to improve starter efficiency with a cold engine (oil temperature < 5°C)?
- At 13% Ng, instead of moving the condition lever to ground idle, move it to flight idle to provide extra fuel flow and Py.
- At 50% Ng, move the condition lever back to ground idle.
What are the risks of starting the engine in high OAT or to apply heavy electric loads shortly after start-up?
The engine RPM (Ng) might be a bit low, which will cause the propeller to enter cautionary or warning mode.
How do you correct for a propeller warning mode after start-up?
- Move the condition lever to flight idle.
- Reduce electrical load on the system.
- Close the bleed air valve.
- Move the PCL aft of the idle detent to reduce proeller pitch.
- If Np > 950 RPM shut down the engine and request maintenance check.
Normal procedures should be resumed prior to taxi.
Can you use flight idle on the ground?
Technically, yes but it is not recommended as it might require continuous brakes application during taxi which might result in hot brakes > blown up fuse plug > flat tire.
How many igniters (spark plugs) are there and where are they located?
- There are 2 spark plugs
- They are located on the engine cowling (combustion chamber section) at 4 and 9 o’clock.
What does the ON position of the IGNITION switch do?
- It continuously ignites the spark plugs until switched off.
- It must be turned ON in heavy precipitations.
What does the AUTO poistion of the IGNITION switch do?
It will automatically ignite the spark plugs when ITT < 500°C with Ng > 10% and will automatically stop after 10 sec when ITT > 500°C or when Ng < 10%.
What type of fire detction system is used in the engine?
- The fire detection system is composed of a tube in wich a hydrogen-charged core is surrounded by helium gas.
- When the temperature increases past a certain point, the core will emit hydrogen, increasing the pressure in the tube that will shift a metalic diaphragm pressing on a small metallic pin to trigger the alarm.
- The normal pressure of the helium in the tube is used to hold an integrity switch between two metallic plates. In case of a leak in the tube, the pressure will be lost, thus releasing the integrity switch and triggering a fault caution on the PFD.
What is the material used for the propellers?
4-blades: Aluminium
5-blades: Composite
What’s the propeller diameter?
2.67 m
What type of de-icing system is installed on the propeller blades?
Electric de-ice boots.
How does the pitch change mechanism work?
- It uses the engine oil.
- The oil is pressurized by a pump located in the CSU.
What’s Np?
The propeller speed (RPM).
To which bus is the propeller feathering mechanism connected?
The Essential Bus.
Where is the pitch control mechanism located?
In the propeller hub.
What’s the relationship between oil pressure and blade pitch?
Low pressure = feather
Medium pressure = fine pitch
High pressure = beta range
What’s the minimum RPM for ground operations?
950 RPM
Where are the OAT sensors located?
There is one under the left wing called the “controller” and one under the right wing called the “comparator”.
What’s the minimu pitch (finest pitch) for flight operations?
6°
How is fuel symmetry maintained?
Automatically by the Fuel Control and Monitoring Unit (FCMU).
Where are the fule drains located?
- One under each wing for the tanks.
- 2 in the fuel service bay (fuel filter and air separator) located left of the nose wheelwell.
What is each tank’s max usable fuel quantity?
201 USG
What type of fuel quantity probes are installed in the tanks?
Capacitance probes connected to the FCMU.
What does the FUEL EMERG SHUT-OFF handle activate?
It mechanically shuts off the firewall valve.
What are the booster pumps used for and where are they located?
They are located in each wing’s collector tank and are used for:
1. Providing fuel pressure during engine start.
2. Fuel balancing
3. Maintaining fuel pressure in case of pressure loss in the circuit.
What are the 2 modes available for booster pumps and what do they do?
- In the ON mode, the pump operates continuously.
- In the AUTO mode (normal operations), the pump will activate in case of a fuel imbalance or if fuel pressure drops below 2 PSI.
Can the booster pump supply pressure to the system all by itself?
Yes.
When will the booster pumps start transfering fuel?
When the fuel imbalance is 68 lbs or more.
What is the maximum fuel imbalance that the booster pump can handle?
267 lbs
What should you do in case of failure of the booster pumps?
Manually select “ON” on the FUEL PUMP switch until the fuel imbalance is resolved.
Where does the FCMU draw power from?
Essential bus + Main bus
What does a green “PUMP” below the analog scale in the fuel window of the PFD mean?
It means that the booster pump is on.
What is the fuel reset button end when is it used?
- It is used after refueling to reset the total amount of fuel on board.
- It can also be used during longer flights to enter a more accurate (and less conservative) measurement of the remaining fuel on board.
2.1. While used in flight the wings must be leveled, pitch +/- 3° and no turbulences to provide an accurate reading.
What’s the maximum fuel imbalance allowed on take-off?
0 lbs
When will the Fuel Low indication appear on the CAS?
When there is less 20 USG left in the tank.
When will the CAS display a Fuel Imbalance caution?
When the fuel imbalance reaches 178 lbs or more.
Which bus are the booster pumps connected to?
The Essential Bus.
What’s the PGDS?
It is a 28V DC Power Generation & Distribution System
What are the constitutive elements of the PGDS?
- Generator 1, 28V, 300A
- Generator 2, 28V, 300A
- 2 batteries of 24V each
- An Emergency Power Supply (EPS) 24V lead-acid battery
What is the PGDS configuration?
- Generator 1 supplies power to the systems connected to channel 1.
- Generator 2 supplies power to the systems connected to channel 2.
- In case of generator failure, the remaining working generator can be connected to both channels through a bus tie.
What will the PGDS do in case of one of the generator’s failure?
- The remaining generator will automatically connect to both channels by closing the tie breaker.
- It will automatically shed non-essential electric loads to avoid overloading the remaining generator.
What does Gen 1 supply energy to?
- The essential bus
- The avionic 1 bus
- The standby bus (via the avionc 1 bus or Hot bat bus ico the avionic 1 bus failure)
What does Gen 2 supply power to?
- The main bus
- The avionic 2 bus
- The non-essential bus
- The cabin bus
- The engine starter
Where are batteries 1 & 2 located?
In the rear fuselage.
What happens when you use the EXT PWR switch?
If an external power source is connected, it will close the tie bus to provide power to both channels.
For how much time can the Emergency Power Supply (EPS) battery provide power?
30 min
What happens when in case of a complete power failure of both generators and both batteries?
The EPS bus will be supplied by the EPS battery and the EPS battery will supply channels 1 & 2.
What are the Power Junction Boxes (PJB)?
They contain contactors, relays and other circuit protections.
Where are the PJBs located?
- Cockpit lower left wall for Gen 1
- Cockpit lower right wall for Gen 2
- In the rear fuselage for the Batteries and External Power (BEPJB)
Which type of systems does the Hot battery bus supply?
The systems that must remain available when the aircraft is powered down.
This is why the hot battery bus is connected directly to battery 1.
Which systems are supplied by channel 1? (6)
- Essantial bus
- Avionic 1 bus
- Flaps
- LH windshield de-ice
- Prop de-ice
- Cabin heating
Which buses have the highest level of integrity?
The Essential and the Avionic 1 buses.
They can be supplied from both generators and both batteries and will be powered in normal, abnormal and emergency situations.
Which systems are supplied by channel 2? (8)
- Main bus
- Avionic 2 bus
- Non-essential bus
- Cabin bus
- Hydraulics
- RH windshield de-ice
- VCCS
- Floor heating
Which buses have the second highest level of integrity?
The Main and Avionic 2 buses.
They can be supplied from both generators and will be powered under normal and abnormal conditions.
Under emergency condotions, the contactor switch of the main bus will open and its load will be shed.
When do you use the standby power bus?
- Before engine start for pre-flight and ATC comms.
- During an emergency situation if additional load shedding is required, switch off AV 1 bus and switch on standby power bus.
What constitutes a normal, abnormal and emergency situation in the electrical system?
Normal = Both generators operating
Abnormal = 1 generator OFF
Emergency = Both generators OFF
Which bus bar breakers are located on the LH breaker panel?
Front = Essential bus
Rear = AV 1, EPS, Standby and Gen 1 buses
Which bus bar breakers are located on the RH breaker panel?
Front = Main and Non-essential buses
Rear = AV 2, Cabin and Gen 2 buses
What is VCCS?
Vapor Cycle Cooling System (Air conditioning)
Where are the breakers for high current consuming systems located (windshield heating, hydraulics, flaps, etc…)
On the respective left and right hand PJBs, except for the VCCS and logo light breakers which are located on the BEPJB.
Can you open and close the bus tie breaker manually (located on the overhead panel)?
Yes
What happens if the MASTER POWER EMEGENCY swith is turned OFF?
It disconnects all generators, batteries and external powers.
Only le Hot Battery and Emergency Power buses will remain powered.
What is the RESET position on the GEN 1 and GEN 2 switches used for?
It is used to allow the generator back on line after a voltage regulator trip.
What happens when you put the EPS switch in the ARM position?
It powers up the EPS bus.
What does a positive BAT current indication displayed on the MFD mean?
The battery is charging.
Which voltage/amps conditions will trigger a battery caution message on the CAS?
- Battery voltage outside of the 22 V / 30.3 V envelope.
- Battery current > 60 Amps.
When will the CAS display a Generator caution message?
When the voltage is outside of the 22 V / 30.3 V envelope.
What’s the correct power up sequence? (4)
- STBY BUS > ON
- EPS > Test (5 sec) then ON
- BAT 1 & 2 > ON
- EXT PWR > As required
To expedite, STBY BUS and EPS > ON before pre-flight and BAT 1 & BAT 2 ON before sitting down.
What’s the correct power down sequence?
- EXT PWR > OFF
- STBY BUS > OFF
- EPS > OFF
- BAT 1 & 2 > OFF
What does a blue ON indicator after switching the STBY BUS ON mean?
Power is available from Hot battery bus.
It will turn off automaticaly once Avionic 1 comes online after engine start.
What precaution should you take prior to applying external power?
BAT 1 & 2 > ON
In case of dual generator failure, which loads in channel 2 will remain powered?
Hydraulics only.
What’s the duration of the timer of the passeger door light?
45 sec
Where are the landing lights located?
One on each main LDG gear.
Where is the taxi light located?
On the nose LDG gear.
Where are the beacon lights located?
- One under the fuselage near the center.
- One on top of the horizontal stabilizer.
When should the beacon be turned on?
- On the ground when engine is running (like the strobes)
- In the air when you require extra anti-collision protection (like strobes)
What are RECOG lights and where are they mounted?
If fitted, they are located in the leading edge of each wing and are used to provide extra visibility.
What is the Evironmental Control System (ECS)?
It is the system that controls the air conditioning, pressurization and cabin temperature.
It comprises:
1. Air Cycle System (ACS) (= Pack)
2. Auxiliary heaters
3. Vapor Cycle Cooling System (VCCS) (if fitted)
4. Vent fans (if VCCS not fitted)
The ECS is the global A/C system.
The ACS is the main A/C system.
The auxiliary heaters are heating boosters.
The VCCS are cooling boosters.
What does the ACS do?
It bleeds air from the engine, cools it, mixes it with warm air and delivers it to the cabin air distribution system. It is basically a pack.
What are the different stages of the ACS?
- Control venturi (bleed air collector)
- Heat exchanger (using ram air as coolant)
- Cooling turbine
- Temperature Control Valve (TCV)
- Water separator
- High pressure shutoff valve
- Firewall shutoff valve
What is the TCV for?
To mix cold and warm air and control the A/C temperature.