Engine Flashcards
1
Q
The oil system is divided into
A
Oil pressure and scavenge system
Total loss lubrication system
2
Q
Oil pressure and scavenge system provides lubrication for
A
Front bearing
Accessory gearbox
Reduction gearbox
3
Q
The total loss lubrication system provides lubrication for
A
Center bearings and rear bearings, through the use of 2 metered pumps.
Oil is then discharged in the atmosphere
4
Q
OIL PRESS light might appear in normal operations during
A
Zero or negative g flight
5
Q
Oil system contains
A
11pints
6
Q
Oil tank dimension
A
13.5pints
7
Q
Oil qty contained in oil tank
A
9.5pints
8
Q
Usable oil qty
A
6.5pints
9
Q
Unusable oil qty
A
3pints
10
Q
Max and min oil consumption
A
1.25pint/h and 0.9pint/h
11
Q
The oil system is capable of ensuring correct engine lubrication for how long?
A
4h 50min
12
Q
Oil qty must be checked within ____ from engine shutdown
A
20mins
13
Q
The oil pump is connected to the engine via
A
The accessory gearbox
14
Q
What does the oil pressure system do?
A
It lubriacates the front bearings, accessory gearbox and reduction gearbox
15
Q
What does the oil scavenge system do?
A
It takes oil used from the pressure system to lubricate, and brings it back to the oil tank
16
Q
OIL PRESS comes on when
A
Pressure drops below 0.4bar or above 2.4bar
17
Q
What is the correct procedure to apply in case of OIL PRESS light?
A
85% RPM
If OIL PRSS is less than 0.4, then advance throttle 95%RPM for 10 sec, if it doesn’t reach at least 0.3bar, bring it back and maintain 85%RPM
18
Q
Engine name
A
Rolls-Royce Viper MK632-43
19
Q
Viper engine nominal thrust
A
17.8kN (at sea level under ISA)
20
Q
BOV blows air when and from where
A
At low altitudes mainly, from 4th stage of the compressor
21
Q
In what direction does the engine rotate?
A
Left (counterclockwise viewed from the back)
22
Q
Max engine RPM
A
13760
23
Q
The Viper is a pure turbojet based on what cycle?
A
Brayton Cycle
24
Q
What is the peculiarity of Brayton Cycle?
A
It is an open cycle (since the engine is open)
25
What are the utilities attached to the accessory gearbox?
GEN1
GEN2
HYD PUMP
High pressure fuel pump
Oil pump
Tachometer generator
26
What is the function of the nose bullet at the early stage of the compressor?
To let the air smoothly flow into the engine, and not becoming turbulent (otherwise compressor stall)
27
Describe Viper structure
Air intakes
Nose bullet
Airflow stabilizers (3)
8 stages compressor
Annular combustion chamber
2 stages turbine
Exhaust cone
Jet pipe
28
How many trimmers are there in the jet pipe? What is their function?
6
Their function is to stabilize the air going out of the turbine and not become turbulent
29
Viper compression ratio
5,9:1
30
In the engine fuel system the RRV (Rate Reset Valve) function is to
Prevent fuel pressure variation coming out from high pressure fuel pump
31
Describe engine fuel system operation
Booster pump
LP filter
Engine Driven pump (RPM governor, RRV)
BFCU (EPC)
AFRC
Fuel flow transmitter
Pressure increase valve
6 atomizers
12 burners (24 nozzles)
32
What does the BFCU do?
1. It controls the fuel pressure and qty to deliver to the AFRC according to:
- Engine Throttle position
- EPC
2. It regulates engine idling
3. It incorporates the 2 fuel cocks connected to the throttle
33
The JPT LMTR system consists of
4 thermocouples (also used for JPT indicator)
JPTLA
EPC
34
JPT indicator in the cockpit receives signals from
The 4 thermocouples
35
The JPTLA senses temperatures thanks to
Through the 4 thermocouples by EMF (Electro Magnetic Field) changing according to the temperature
36
What does JPTLA do?
It compares EMG measurements (coming from thermocouples) to EMG preset values.
According to this it communicates with EPC for reducing fuel pressure in the BFCU
37
How does the EPC operate?
It is composed of a small pipe inside another pipe. When EPC receives signal from the JPTLA, it closes the small pipe, reducing the fuel qty and pressure going through the BFCU
38
JPT Limiting System can be affected by temporary overshoots during
Climbs at 100%RPM
Level flight at high altitude (above FL300), and moving the throttle to 100%RPM
39
EGT overshoots must never exceed _____ for more than _____
790ºC
10sec
40
Engine anti-ice system is provided by which bus?
Primary bus
41
ANTI-ICE/ENGINE switch when moved to on in flight operates
The anti-ice valve, that let hot bled air to reach the nose fairing (pin)
and
the resistors in the ducts and lips.
42
In case of electrical supply failure the anti-ice valve
Fails to the open position
43
To run the anti-ice test on the ground you must
Set power not less than 60%RPM
Move the ANTI-ICE/ENGINE switch to TEST
44
Why is it so important to heat the nose fairing (pin) with engine anti-ice system?
Because preventing ice formation on the pin, the airflow will be smooth and not turbulent, thus preventing compressor stall
45
What should you check during ANTI-ICE/ENGINE test?
RMP decreasing
TEMP increasing
LOADMETER increasing
46
The igniters power comes from
Essential bus
47
Igniters are fed with alternate current, but power comes from 28vDc essential bus. How is it possible?
AC Ignition Units convert power coming from essential bus into high-voltage alternating current to feed the igniters
48
The engine should light up within _____ from starter engagement or _____ from moving the throttle to idle. The system will automatically abort the start if the engine is not at self sustaining speed after ____
20sec
15sec
25sec
49
What is the action to take if the engine doesn’t light up within 20sec from starter?
Engine throttle STOP
ENG MSTR - OFF
In case of HOT START only Engine throttle STOP
50
The engine start sequence can be interrupted any time by
Moving the ENG/MSTR switch to OFF
51
ENG/MSTR switch controls
The starting system
The booster pump
That is why when you move the switch to ON prior to engine start, you check for BAT 1/2 and F. PRSS OFF
52
In what position the Engine Throttle operates the High Pressure Cock?
In the first range of travel (up to IDLE)
53
The High Pressure Cock moved by the engine throttle is incorporated in what unit?
BFCU
54
During engine start sequence, fuel coming through the AFRC and Fuel Flow Transmitter than goes into the
Starting Valve
55
How can the starting system automatically abort start sequence if self sustaining speed is not reached within 25sec?
By closing the Starting Valve, and de-energizing igniters and starter
56
Minimum windmilling is ____, but normally its value is ____
8-10%RPM
13%RPM
57
When is the starting valve open?
During engine start
During relight ops
58
The fire and overheat detection system is composed of
Fire detection system (front)
Fire and overheat detection system (rear)
59
Where do Zone1 and Zone2 in fire and overheat detection system start from?
From the stainless steel firewall installed just after the engine compressor
60
Higher temperature in Zone1 triggers _____ while in Zone2 triggers _____
FIRE
OHEAT
61
Fire in Zone1 can be more dangerous because of
Explosion hazards
Damage to structure and flight controls
(Fuel, Oil, Hydraulic etc are all in the front)
62
OHEAT light can also be triggered by
Hot gases escaping from the jet pipe
63
Minimum engine inflight temperature is
200ºC
64
Normal engine continuous inflight temperature is
300ºC - 670ºC
65
Igniters are located
In the combustion chamber at 4 and 8 o’clock position, in proximity of the atomizers to guarantee ignition
66
The fire and fire and overheat systems are capable of detecting both
Average temperature
Hot spot temperature
67
The HP Fuel Pump sends fuel at a pressure of
600-700psi
68
What does AFRC unit do?
According to the altitude and phase of fight, it manages the quantity of fuel to let in the combustion chamber according to the air quantity
69
When at low altitudes, BOV is open every time RPM are below_____.
It closes with increasing power at _____.
It opens again with decreasing power at _____.
78-80% RPM
80%RPM
78%RPM
Values referred to ISA
70
The exhaust cone has an inner case secured by
9 radial stay pins
71
What is the function of the Jet Pipe?
To direct gases in order to produce thrust
72
How many Nozzles, Burners and Atomizers in the combustion chamber?
12 burners (24 nozzles)
6 atomizers
73
Why the engine throttle is moved to idle only at 10%RPM?
Because at that rotation speed the HP fuel pump is providing enough pressure to the fuel going through the starting valve to be vaporized from atomizers during engine start.
If the system lets in fuel prior than 10%RPM the combustion chamber could be flooded, and therefore there’d be no ignition, or worse an explosion.
74
JPT limit
756ºC +5-12
75
JPT LMTR switch is located
In the front cockpit only
76
When are atomizers and igniters used?
During engine start and relight only.
NB. Secondary function of atomizers is to provide a bit of fuel during normal ops to prevent their obstruction.
77
HOT RELIGHT parameters
Below 20.000ft
Airspeed 120-200kias (150kias suggested)
78
COLD RELIGHT parameters
Below 20.000ft
Airspeed 120-150kias
79
Pressure increasing valve operation value
80psi
80
Primer check valve operation value
40psi
81
Why the engine is radioactive?
Because the compressor outer casing is made of Thorium (Th)
82
In what circumstances during takeoff you turn on engine anti-ice?
Temp<6ºC and humidity >50%
Or
Visibility<500mt
83
The fire and overheat detection system include 2 tests:
Failure Indication Test (by the pilot)
Failure Detection Test (by ground crew)
84
Illumination of FIRE SYS or OHT SYS cautions means that
The respective system is faulty
85
In case of FIRE/OHEAT illumination, what can be done by the pilot to confirm fire?
Run a test of the lights, if the FIRE/OHEAT doesn’t illuminate, then this is another indication of fire
