Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

work > Engine and Engine controls > Flashcards

Engine and Engine controls Flashcards

1
Q

What kind of engine do we have

A

T700-GE-401C front drive turboshaft engine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the 5 sections of the engine

A

inlet compressor combustor turbine exhaust

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

air flow through engine

A

through inlet cowling then to swirl vanes inlet particle separator deswirl vanes compressor combustor gas generator turbine power turbine then out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

describe the compressor section

A

5 stage axial and single stage centrifugal system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

describe the combustion section

A

flow through annular combustion chamber
2 igniters
12 fuel injectors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

function of gas generator turbine

A

drives the compressor and AGB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

describe the gas generator turbine

A

two stage air cooled high performance axial design

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

which turbine shaft turns inside the other

A

Np spins inside Ng

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does the Np turbine do

A

drives high speed output shaft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

where is TGT sensed

A

between Ng and Np turbines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how much of the total airflow is used for combustion

A

about 30%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the airflow not used for combustion used for

A

compressor inlet temp (T2) air
compressor discharge (P3) air
combustor and turbine cooling
engine oil seal pressurization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does the AGB drive

A

starter, HMU, IPS blower, ODV
alternator, eng driven fuel boost pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

goal of the engine control system

A

proper and complete control of the engine to maintain a constant Np and Nr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

major components of engine control system

A

HMU
ODV
EDECU
Alternator
series of fuel flow control valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

general function of HMU

A

provides Ng control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

general function of EDECU

A

trims the HMU to meet Np requirements and lessen pilot workload

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does putting the PCL in the off position do

A

PAS mechanically shuts off fuel at the shutoff valve in the HMU

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what does putting the PCL in the idle position do

A

Controls HMU to auto control start sequence to get to self sustaining combustion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what does putting the PCL in fly do

A

sets max level of power that could be supplied if demanded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what does putting the PCL in lockout and back do

A

disables TGT limiting, load sharing and Np governing and allows for manual control of Np and Ng

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

how to get engine back to normal from lockout

A

idle then fly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what does the solenoid on the quadrant do

A

prevents moving engines past idle with rotor brake on unless the override tab is pulled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

function of the load demand system

A

routes collective input to control HMU to auto control engine speed and provide required power

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
function of eng driven fuel boost pump
provides reliable suction feed to eng suction to reduce likelihood of fire hazard and provides enough pressure to meet requirement of HMU/high px fuel pump
26
does the engine fuel filter filter water
no
27
how does fuel get to fuel filter and where does it go
from eng driven fuel pump to HMU high px fuel pump
28
can the PDI on the eng fuel filter be reset
only by removing the filter element and bowl
29
what gives us the #1/2 fuel fltr bypass caution
electric switch attached to bypass valve
30
what does HMU stand for
hydromechanical unit
31
what is in the HMU
High px fuel pump Ng governor metering valve linear variable displacement transducer torque motor servo variable geometry vane servo vapor vent shutoff valve
32
how does fuel go through the HMU
enters at high px pump through metering and shutoff valve sent to the oil to fuel heat exchanger while some fuel is used to position metering valve, variable geometry vane servo start valve and amplify T2,P3, Ng signals, then goes to ODV
33
2 mechanical and one electric link to HMU
MECH: LDS (collective) and PCL (PAS) ELEC: EDECU moves torque motor servo to precisely trim Ng
34
what does the PCL input to the HMU provide
fuel shutoff start fuel flow with auto acceleration set permissible Ng to max fuel priming EDECU Lockout
35
what other signals then the main 3 does the HMU respond to
T2,P3, Ng which help control variable stator vanes and anti ice/start bleed valve to reduce likelihood of compressor stall
36
how does the HMU act when there is no EDECU input
like a conventional gas generator
37
what does the HMU provide
fuel scheduling for min/max fuel flow and variable stator vane control
38
how does the HMU respond to the torque motor servo input from the EDECU
LVDT passes feedback signal to prevent hunting
39
what happens to excess fuel from HMU
rerouted to pump inlet
40
Ng overspeed valve trip point
110 +/- 2%
41
what 2 reasons does the PAS set power available above what is required
fail safe to high power in the event of an electrical failure to the torque motor the system resets to max power OEI conditions
42
What does the HMU provide
Rapid engine transient response through collective compensation Auto fuel scheduling for eng start Ng overspeed protection Ng governing Acceleration limiting Flameout and compressor stall protection
43
describe the Ng overspeed protection provided by HMU
if Ng reaches the 110 +/-2% a valve secures fuel flow to the engine until the overspeed condition is gone
44
describe the Ng governing provided by the HMU
uses T2, P3, Ng to schedule fuel flow
45
describe the Acceleration limiting provided by HMU
ensures PCL motion will not damage the engine or cause inadvertent shut down
46
describe the flameout/compressor stall protection afforded by the HMU
moves variable geometry vane and anti-ice/start bleed valve to prevent compressor stall instability
47
what is the ODV
overspeed and drain valve
48
4 functions of the ODV
provides fuel flow to the 12 fuel injectors purges main fuel manifold overboard post shutdown to prevent coking traps fuel upstream in fuel/oil heat exchanger so we don't have to keep priming returns fuel to HMU in Np overspeed energized or EDECU hot start preventer activated
49
what 2 conditions will the HMU limit fuel flow separate from other limits
combos of T and press alt with a high power required setting where the fuel lines are simply not big enough to provide the required fuel Ng/T combo that protects the compressor section - usually cold temps
50
what does the alternator power
ignitor assembly EDECU Ng signal to the vertical instruments
51
what does EDECU stand for
enhanced digital electronic control unit
52
what are the control parameters of the EDECU
Np sensing (governing) Np overspeed and Q sensing TGT monitoring
53
cockpit signals to EDECU
ENG spd trim switch Cpow switch ENG ovspd test A and B
54
helicopter signals to edecu
torque from other EDECU Np demand 400 Hz backup power HMU (LVDT)
55
Signals from EDECU to cockpit
Torque Np TGT Cpow
56
how many EDECU functions are there
16
57
What are the EDECU functions
Np governing Np overspeed protection Np overspeed test Ng decay relight Cpow manual Cpow auto Cpow dual auto hot start prevention eng load sharing fault diagnostic system transient droop improvement auto ignition system signals cockpit TGT limiting eng speed trim DECU lockout
58
describe EDECU Np governing
Np sensor on the left of Np section sends an Np signal to the EDECU that is comparted to a reference Np
59
describe EDECU Np overspeed protection
Uses signal from Np overspeed and Torque sensor on right side of Np section. when Np>120 sends a signal to ODV to divert fuel to HMU causing a flameout
60
can we reset popped eng ovspd CB in flight
shall not
61
describe EDECU TGT limiting
measured is compared to a reference TGT, if above it signals to reduce fuel flow. when TGT gets to 878, it prevents any further increase in fuel flow has a max rated power limiter that will stop TGT at 866 +/- 10
62
describe EDECU eng load sharing
both EDECUs share their torque level and the system will try to raise the torque of the lower eng to the higher
63
describe EDECU eng speed trim
speed trim witch can manipulate EDECU reference between 96 and 101%
64
describe EDECU manual cpow
uses the switch to change the TGT limit from 878 to 903 but like normal it will prevent further fuel flow at 891 +/-10 also deactivates ECS only cpow that gives us a signal it is on
65
describe EDECU auto cpow
happens in OEI conditions when Q of one engines falls below 50%, the 866+/-10 is changed to 891 +/-10
66
describe EDECU dual cpow
makes the switch from the 866 +-10 to 891+-10 if one or more of the following conditions exist Np<96 greater than 3% droop from ref Np and actual Np greather than 5%/sec droop in Np if Np less than or equal to reference point
67
describe EDECU overspeed test
only when Np>96% artificially lowers the Np overspeed limit from 120 to 96 causing flameout
68
describe EDECU lockout
disable torque motor servo and thus deactivates TGT limiting, Np governing, and load sharing retains Np overspeed protection
69
Describe EDECU cockpit signals
provides Np, TGT, and torque signals to to DTC for cockpit display
70
Describe EDECU hot start prevention
if TGT exceeds 900 with Ng <60 and Np<50 auto stops fuel flow restores when TGT gets down to 300 c or after 25 seconds whichever is first can be disabled by holding one of the overspeed buttons for the whole start auto tests in Np overspeed test
71
describe EDECU transient droop improvement
using signals from TDI Nr sensor on left accessory module and a collective position sensor in the mixing unit, will increase fuel flow early at low torque settings when collective demand increases rapidly or rapid Nr decay
72
describe EDECU auto ignition system
turns the ignition system on for 5 seconds when Np overspeed sys activates
73
describe EDECU Ng decay relight feature
if an engine flames out and exceeds normal Ng decay rate, the system will turn on an ignition sequence for 5 seconds disable below 62% Ng
74
describe EDECU fault diagnostic system
assesses signals and tells us after shutdown if something is wrong
75
what is considered clearing an EDECU fault code
stabilize above 425 deg in fly or idle then do a normal shutdown
76
EDECU fault code 15
may result in EDECU driven eng control failure and may damage engine
77
EDECU fault codes and AFCS
presence of unsuppressed codes will prevent AFCS ground checks and auto blade fold because it is sending a torque code
78
what makes up the ignition system
ignition exciter unit 2 ignition plugs
79
component of the start system
engine starter, start valve, check valves, controls, ducting
80
when does starter dropout normally occur
52-65%Ng
81
how can we disengage the starter
pull down PCL pull its CB remove the air source
82
how can you override a malfunctioning starter
hold it in until normal starter drop out speed
83
if the apu is running can we do a crossbleed start
no
84
what is the minimum Ng of the receiving enging for a crossbleed start prior to idle
24%
85
What is the generally required range of Ng on the donor engine for crossbleed
90-94%
86
where is Np sensed
two sensors at the top of the exhaust frame that receive electrical pulses from "teeth" brushing against
87
left vs right Np sensor
left sends Np signal to EDECU and vertical instruments Right is used to compute torque and is used in the Np overspeed system (still fed through EDECU)
88
where does the Ng signal in the cockpit come from
alternator
89
how many thermocouples are there
7

work (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions