Powerplant Flashcards
(34 cards)
Overview 1
The Citation Soverign has two rear mounted Pratt and Whitney PW306 engines.
The PW306C engines are high bypass ratio turbofan engines that develop 5770 pounds of thrust at sea level to 31 degrees celcius.
Overview 2
Each engine is controlled by a dual channel full authority digital electronic control (FADEC) unit on each engine.
A forced mixer exhaust nozzle reduces noise levels and increases performance.
Overview 3
The PW306C is a twin spool, FADEC controlled turbofan engine.
An inner shaft (N1) consists of a fan assembly that is driven by a three stage low pressure (LP) turbine.
The outer shaft (N2) consists of four axial stages and one centrifugal stage of the compressor driven by a two stage high pressure (HP) turbine.
Where are all engine driven accessories found?
On the accessory gearbox.
What drives the accessory gearbox?
A direct drive tower shaft geared to the N2 section drives the accessory gearbox.
The compressor bleed-off valves prevent compressor surge and stall during? (3)
- Start.
- Low-rpm operations.
- During transient power conditions.
How do the compressor bleed-off valves prevent compressor surge and stall?
The solenoid operated valves allow compressor air into the bypass ducts.
How many bleed-off valves are there?
Four.
What controls the bleed-off valves?
The FADEC.
What systems are driven by the accessory gearbox? (6)
- Starter-generator.
- Oil pumps.
- Alternator.
- PMA.
- Fuel pump.
- Hydraulic pump.
When the ignition toggle switch is in the ON position, what happens?
Continuous ignition is selected.
When the ignition toggle switch is in the OFF position, what happens?
All power is removed from the exciter boxes.
When the ignition toggle switch is in the NORM position, what happens?
The FADEC has control of the ignition operation.
When will you see the following CAS message displayed, ENGINE CONTROL FAULT?
When the ignition toggle switch is not in the NORM position.
Engine sync button.
During flight with the landing gear up, throttles above idle and below the TO detent, and the ENGINE SNYNC button in NORM, the left and right FADECs continuously monitor and adjust the engines to match.
L and R Engine start buttons.
Engine start is initiated by pressing the ENGINE START button.
When the respective start relay is closed, the button illuminates.
At 44% N2, the relay opens and the button extinguishes.
Start disengage button.
This button illuminates when the START button is pressed and extinguishers at 44% N2.
It is used to terminate a start or to open the start relay if it fails to open during start.
What does the pilot event marker do?
It allows the pilot to record engine parameters into EDU memory in the event of abnormal engine operation.
Pressing the button momentarily records a 5 minute trace.
4 mins prior and 1 min after activation.
Describe the ENGINE OIL SYSTEM.
The oil system consists of an oil filter and tank, a pressure pump, scavenge pumps, and a fuel/oil heat exchanger.
Oil passes through the fuel oil heat exchanger and is sent to the No1, No2, No3, and No4 bearings and the N2 tower shaft brushing.
OIL FILTER BYPASS VALVE
If the oil filter becomes contaminated, restricting the flow of oil through the filter, a bypass valve opens, allowing unfiltered oil to flow to the engine.
The OIL FILTER BYPASS CAS message is displayed on the EICAS, indicating an impending bypass situation.
For extremely low oil temperatures during engine starts, the CAS message is inhibited.
OIL PRESSURE TRANSDUCER
A pressure transducer and differential pressure switch monitor oil pressure.
The transducer provides input to the EICAS for analog indication.
The differential pressure switch activates a red CAS message OIL PRESSURE LOW L-R and illuminates the L-R OIL PRESS annunciator if oil pressure drops below 20 psi.
Where is the fuel from the tanks delivered?
To the HFCU, HYDROMECHANICAL FUEL CONTROL UNIT.
Where is HFCU found?
On the accessory gearbox.
Describe the journey of the fuel.
From the fuel tank it’s sent to a HOPPER TANK; then through the FIREWALL SHUTOFF VALVE, PRESSURE SWITCH, LOW PRESSURE ENGINE FUEL PUMP, FUEL OIL HEAT EXCHANGER, HIGH PRESSURE ENGINE FUEL PUMP, HFCU, FUEL FLOW TRANSDUCER, FUEL NOZZLES.
