SYS - Propulsion 1 Flashcards
1
Q
SHP rating?
A
1100SHP
2
Q
Which flow direction for engine?
A
Reverse flow
3
Q
Two general sections of the engine?
A
Gas generator section
Power turbine section
4
Q
What type of compressor?
A
Four stage axial flow followed by a single stage centrifugal flow compressor
5
Q
What makes up the gas generator section? (4)
A
- four stage axial flow compressor
- single stage centrifugal flow compressor
- combustion chamber
- single stage compressor turbine
6
Q
What parts make up the power section? (3)
A
- two stage axial flow power turbine
- exhaust case
- reduction gearbox
7
Q
What powers the compressor section?
A
The single stage compressor turbine
8
Q
What powers the reduction gearbox?
A
The two stage power turbine
9
Q
Oil system capacity?
A
18.5 US quarts
10
Q
Oil system lubricates? (4)
A
- engine bearings
- reduction gears
- accessory drives
- propellor
11
Q
Oil level must be serviced within how many minutes after shutdown?
A
30min
12
Q
Best time to check oil level?
A
15-20min after shutdown
13
Q
What must be used for checking the oil?
A
Only the dipstick, not the sight glass
14
Q
Four systems within the oil system?
A
- Pressure
- scavenge
- cooling
- breather
15
Q
How does oil system work inverted?
A
Two pick up systems, one at centre of tank, one at top
16
Q
Where is oil cooler?
A
- located in lower aft cowl
17
Q
How many scavenge pumps and where?
A
Two pumps, on inside and one outside of accessory gearbox returning scavenged oil from bearings and gearbox
18
Q
How oil filtered? (2)
A
Main oil filter and and several oil strainers
19
Q
How oil breathed?
A
Oil breather valve and centrifugal breather
20
Q
Why can oil pressure display up to 4 PSI when engine shutdown?
A
Design of the transmitter
21
Q
What happens if main oil filter blocks?
A
A filter bypass valve allows unfiltered oil to continue to lubricate engine
22
Q
Where is oil press and temp measured?
A
Downstream of main oil pump
23
Q
How does a low oil pressure signal activate EICAS?
A
Signal is sent to engine data manager (EDM), then to signal conditioning unit (SCU), then to EICAS
24
Q
When does oil low pressure red warning indicate? (2)
A
- below 40psi when above idle
- below 15psi at idle
25
When is Amber oil pressure caution light on?
- 15-40psi at idle
| - 40-90psi above idle for greater than 10sec
26
What will illuminate both Amber and red oil pressure warnings?
- 15-40psi for 5 sec or more
27
Action if a single momentary illumination of Amber oil pressure?
Nil, may not indicate a malfunction if manoeuvring
28
Illumination of bob red and Amber oil pressure lights whilst gauge indicates normal pressure indicates?
SCU failure
29
Reduction gearbox is a two stage reducing turbine shaft speed from _________ rpm to propellor operating speed of _________ rpm
30000 to 2000
30
What detects metal contamination in reduction gearbox?
Chip detector in RGB activating an EICAS CHIP warning message
31
Where is engine power output (torque) measured?
Reduction gearbox
32
Can you feather the prop?
Yes
33
What items come off the RGB?(4)
- permanent magnet alternator
- torque probe
- propellor interface unit
- air conditioning compressor (belt driven)
34
What rpm does 100% Np represent?
2000rpm
35
What two units control propellor blade angle and speed?
PMU (power management unit) and PIU (propellor interface unit)
36
100% torque available up to what altitude band on a standard day?
12000-16000ft
37
Low pitch blade angle approximately how many degrees?
15deg
38
What direction does the spring inside the PIU try to send the prop?
Towards feather - feathering spring
39
What does an increase in oil pressure through the PIU do?
Goes against the feathering spring pressure and tries to fine the prop
40
What does the mechanical overspeed governor in PMU modulate oil pressure to do?
Limits Np to below 106%
41
What does electronic governor limit Np to?
100%
42
When PMU fails, what does mechanical overspeed governor limit Np to?
100+/-2%
43
When in mechanical governor overall how is it kept on speed?
Mechanical overspeed governor uses flyweights to dump oil pressure and fine the prop until feathering spring returns it toward coarse - balancing between the two
44
If engine failure with PCL not in cut off, what will happen to prop?
Slowly go toward feather due to feathering prop, but likely not all the way - no engine oil pressure to make it go fine
45
Two methods of feather prop when Engine shutdown and PMU is in NORM?
- PMU sends a signal to prop servo valve to drain the oil
| - PCL cutoff activates micro switches that power the feather dump solenoid which also dumps the oil
46
What does the PROP SYS circuit breaker power in the feathering system?
The feather dump solenoid
47
If PROP SYS circuit breaker is pulled how is prop feathered?
Only via prop servo valve
48
If PCL is placed in cutoff with PMU off and PROP SYS circuit breaker pulled what will happen?
Prop will only slowly feather and may not fully feather until after landing.
49
If a red X appears on rpm on torque gauges what could this mean and what do?
PMU has gone to manual mode from either a PMU sensor exceedance, eg rapid feathering, or a sensor failure. Cycle the PMU sweet rich and if they remain en it is a sensor failure.
50
Three positions of the starter switch?
Norm, manual, auto/reset
51
Two positions of ignition switch?
On and Norm
52
When ignition switch is on and starter moved to auto/reset what happens to the ignitors?
PMU automatically energise and de-energises them
53
When is green IGN SEL light on? (2)
When igniters activated in AUTO mode or ignition switch set to on
54
How is the PCL connected to the FMU?
Mechanically and electrically (electrical through the PMU)
55
PCL friction is only in which cockpit?
The front
56
Caution: do not ____________ if the PCL is inadvertently moved to cutoff and engine is winding down.
Move the PCL back to idle as severe engine damage could occur
57
What powers the PMU?
The Permanent magnet alternator (PMA) on the RGB when engine running, or battery bus below 40-50% Np
58
Two modes of PMU?
Ground and flight
59
Idle settings of PMU? (3)
Ground - 60-61% N1
Flight - 67% N1
Flight - raises N1 so Np stays above 80% above 10000ft to avoid stress on propellor during spins
60
Can PCL be moved rapidly?
Yes, PMU protects engine
61
When does PMU automatically stop an AUTO start? (2)
- no light off within 10sec of selecting AUTO/reset
| - PMU projects an impending hung or hot start
62
PMU parameters for hung (1) and hot start (3)?
hung - N1 acceleration rate to idle is less than 50% of normal
Hot - ITT exceeds 940 for 2 sec, 870 for 4sec, or 840 for 19 sec
63
What factors can cause an aborted PMU start? (5)
- weak battery
- high DA
- high pressure start ITT
- high OAT
- tailwind
64
Where does PMU receive input for Temp for engine start? And what is problem with that?
IOAT gauge in engine inlet plenum - during hot a,Brent temperatures a hot engine can heat soak the IOAT further - above 121dec C IOAT the PMU goes offline
65
Briefly describe AUTO start sequence.
- When ST READY indicated for more than 3 sec and AUTO/Reset selected then PMU activates starter, boost pump, infinities, adds fuel at correct N1 speed. At approx 50% N1 the starter and igniters are de-energised and boost pump deactivated if fuel pressure above 10psi
66
How does propellor unfeather during engine start?
Automatically as oil pressure rises
67
When can PCL be moved to idle during engine start?
Anytime after N1 is at or above 60%
68
What do you lose if the ST Ready light goes out anytime during the start sequence?
The PMU will no longer provide any automatic protection and you will have to manually stop the start by moving the PCL to cutoff, or if the PCL has not been moved past the IdLE gate the, by selecting the starter switch to AUTO/reset to regain AUTO protection. If the PCL has been moved past the IDLE position the PCL must be moved to off.
69
What is not provided by the PMU during an airstart?
Automatic engine protection -the pilot must monitor N1, ITT and torque limits
70
What two indications PMU is in manual mode?
PMU FAIL warning and PMU STATUS caution
71
What does PMU do for engine control in manual mode and what must pilot ensure?
- PMU schedules fuel directly to the engine through FM
| - pilot must exercise care to ensure N1, temperature, torque limits are not exceeded
72
How is propellor controlled when PMU is off?
- operating on the overspeed governor
73
What could PMU STATUS caution in flight mean and what performance impact could it have?
Problem with PMU airborne or mismatch with weight on wheels switch and PMU will not revert to ground mode upon landing - possibly keeping the idle in flight mode and affect landing performance.
74
Are starts recommended with PMU off? What do if you want to?
No, but if you do must exercise caution to avoid hot start and also use 'PMU Off Ground Start' procedure
75
Will then be a power step change when PMU fails? When most prevalent and but how much? (2)
Yes, most noticeable cold and low, max increase 280shp and max decrease 550shp
76
The accessory section contains what four systems?
- accessory gearbox
- oil tank
- starter/generator
- battery
77
What are the two main functions of the PMU?
- processes power requests from PCL
- keeps the engine and propellor within operating limits
- determines available power and provides a near linear power response between idle and maximum power
78
Three limits that PMU maintains?
- ITT
- Torque
- Np
79
When PMU switch is off what must the pilot monitor manually?
- engine limitations
80
What voltages does the starter/generator provide for the main electrical system and the battery?
- 28vdc for the main electrical system
| - charges the battery up to 24vdc
81
If oil level is at or below ________, service the oil to ________ .
- ADD
| - MAX HOT
82
Properly angle of a feathered propellor is approximately how many degrees?
- 86deg
