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S76D SYSTEMS > Chapter 6. Powerplant / ENGINES > Flashcards

Chapter 6. Powerplant / ENGINES Flashcards

Learn about the engines installed on the S76D

1
Q

What type of engine is on the S76D?

A

Two Pratt & Whitney P&W 210S free turbine turboshaft engines

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2
Q

What maintains the engines at desired power levels?

A 
A dual channel Full Authority Digital
Engine Control (FADEC) maintains engine
output at desired power level
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3
Q

How are the throttles connected to the FADEC?

A

The throttles are connected electrically to the FADECs.

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4
Q

What is the 30 Sec OEI shaft horse power of the S76D engine?

A

1,123 Shaft Horsepower.

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5
Q

What are the major sections of the S76D engines

A 
The P&W 210S engine has four major sections
or stages.
• Intake—Delivers ambient air to the com
pressor
section for axial and centrifugal
compression
• Compressor—Combines one axial and
one centrifugal compressor to deliver
high pressure air (P3) to combustion
section
• Combustion—Energy produced by the
combustion process is extracted by the
NG gas turbine to rotate the compres
sor
assembly and by the two Np power
turbines to rotate the engine output shaft
leading to the main gearbox
• Turbine and exhaust
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6
Q

What drives the compressor section?

A

The NG Turbine.

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7
Q

what are the other uses of the high pressure (P3) air delivered by the compressor?

A

it is used for combustion cooling, bearing sealing, and bleed air operations. (Heating and cooling)

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8
Q

How many igniter plugs are in the combustion section and where are they located?

A

The combustion section contains two ignitor
plugs at the 4 and 8 o’clock positions and 13
primary and secondary nozzles. The igniters are
only used for starting.

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9
Q

what controls the igniter plugs in the combustion chamber?

A

The Electronic Engine Control (EEC)

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10
Q

In what direction does the Ng and Np rotor assemblies turn?

A

Both NG and Np engine rotor assemblies turn
independently from each other and in opposite
directions (free turbine engine concept). The
NG turbine wheel turns counterclockwise. Np wheel turns clockwise.

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11
Q

what are the systems driven by the accessory gear box?

A 
The compressor rotor drives the following accessories:
• DC starter-generator
• Fuel control unit (FCU) with integral fuel
pump
• Oil pump (not shown)
• Permanent magnet alternator (PMA)
integrated in the FCU
• Air cooled oil cooler (ACOC) blower
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12
Q

What supplies Np and TQ indications to the cockpit?

A

The second stage reduction gear of the power turbine incorporates a phase shift torque metering device (phonic wheel) with sensors that supplies Np and TQ
inputs to both electronic engine controls (EEC
Channel A and Channel B) for FCU control
as well as accurate cockpit indications of TQ
and Np.

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13
Q

What is the T6 system?

A

Engine exhaust temperature is referred to as
the T6 system. It consist of a braided wiring
harness with eight individual thermocouple
probes connected in parallel and installed on
the exhaust casing.

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14
Q

What is the total capacity of the engine oil tank?

A

The engine oil tank has a total capacity of 1.34 gals (5.12 liters)

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15
Q

What are the two ways the engine oil is cooled before being sent to the various engines components?

A 
The oil under pressure is sent to the air cooled
oil cooler (ACOC) driven by the AGB/RGB for cooling before being sent to the fuel oil heat exchanger (FOHE) that acts as the secondary cooling method for the oil system.
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16
Q

How many fuzz burn chip detectors does each engine have?

A

each engine has a single fuzz burn chip detector

and a engine page on the MFDs to indicate oil temperature (MOT) and pressure (MOP).

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17
Q

What provides the engine oil and engine temperature indications on the MFDs

A

A dual function sensor provides main oil pressure
(MOP) and oil filter impending bypass
indications.

The impending bypass functions of the sensor measures the pressure drop across the filter to provide an “impending clogged” oil filter condition to
the pilot by illuminating the caution ENG 1/2
OIL IMP BYPASS on the Warning Caution
Advisory (WCA) panel on the MFD.

A single function sensor provides main oil
temperature (MOT)

The MOP and MOT parameters are measured
immediately downstream of the oil filter on the
oil pressure path. The EECs power and read the
MOP and MOT. Information is then sent to the
MFDs for display in the cockpit.

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18
Q

What is the function of the cold start valve

A

Excess oil pressure is bypassed from the oil
pressure pump outlet into the oil tank via the
cold start valve (CSV). This valve is similar to a thermostatic bypass valve. It opens at 200 psi.

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19
Q

What powers the chip detectors / Chip detector processors CDP

A

The No 1 DC ESS bus

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20
Q

After how many attempts will the chip burner stop trying to burn the chip?

A

Six attempts.

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21
Q

How is the ENG CHIP caution generated?

A

After six attempts to burn the chip, the chip detector will will send a signal to the aircraft’s chip detector processor (CDP) which passes the information to the appropriate VMM which processes the information to display the ENG CHIP message on the WCA.

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22
Q

How many fuzz burn magnetic chip detectors are in the aircraft and where are they located??

A

There are six fuzz burn magnetic chip detectors.

Two engines (one chip detector per
engine)
• Two main gearbox (MGB)
• One intermediate gearbox (IGB)
• One tail gearbox (TGB)
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23
Q

What adjusts the oil pressure to its normal range in the engine?

A

The manually preset pressure adjustment valve (PAV)

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24
Q

At what pressure does the ENG 1/2 OIL IMP BYPASS caution light illuminate and at what pressure does it actually bypass?

A

The MOP sensor activates the ENG 1/2 OIL IMP BYPASS caution light
illuminates at 25 psid; the filter is bypassed at
35 psid.

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25
Q

Below what pressure does the ENG OIL 1/2 PRESS caution light illuminate?

A

The MOP also activates an ENG 1/2
OIL PRESS caution light when the oil pressure
drops below 37 psi.

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26
Q

Above what temperature will the ENG 1/2 OIL HOT caution illuminate?

A

A single function sensor
(MOT) measures oil temperature. The ENG
1/2 OIL HOT caution light illuminates when
the MOT senses oil temperature above 130°C

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27
Q

What are the components of the engine fuel system?

A 
The engine fuel system includes the following
components 
• Fuel control unit (FCU)
• Fuel pressure sensor
• Fuel flow divider (not shown)
• Fuel pump and filter
• Fuel nozzles
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28
Q

What drives the FCU?

A

the Accessory/Reduction gear box (AGB/RGB) drives the FCU

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29
Q

What makes up the FCU?

A

The FCU contains the fuel pressure sensor, EEC channel

A, and EEC channel B.

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30
Q

How many electrical connections are provided to the FCU?

A

Three electrical connections are provided
to the FCU assembly. One connection provides
fuel pressure and blockage information
to the FADEC channels. An electrical connection
is provided for each EEC channel on
the FCU assembly to facilitate commands
from the FADEC. These two connectors are
interchangeable.

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31
Q

What powers/commands the stepper motor?

A

The stepper motor is electrically commanded by either EEC channel A or B.

32
Q

What is the function of the fuel pressure sensor?

A

The fuel pressure sensor is a dual function sensor on the FCU that provides low fuel pressure indication and fuel filter impending blockage indication

33
Q

At what pressure will the ENG FUEL IMP BLKG caution illuminate?

A

The fuel filter impending blockage transducer
measures the pressure drop through the fuel
filter. With an 8 psid pressure drop, the EEC
triggers illumination of the caution ENG FUEL
IMP BLKG on the WCA. When fuel pressure
drops to 16 psi, the warning ENG 1/2 FUEL
PRESS message displays on the WCA.

34
Q

At what pressure will the ENG 1/2 FUEL PRESS warning illuminate?

A

The fuel filter impending blockage transducer
measures the pressure drop through the fuel
filter. With an 8 psid pressure drop, the EEC
triggers illumination of the caution ENG FUEL
IMP BLKG on the WCA. When fuel pressure
drops to 16 psi, the warning ENG 1/2 FUEL
PRESS message displays on the WCA.

35
Q

How can you repair or adjust the fuel pressure sensor?

A

The fuel pressure sensor is powered through the

EECs. No repair or adjustment is possible for the fuel pressure sensor.

36
Q

What is the function of the fuel flow divider?

A

> The fuel flow divider valve divides the metered
fuel between the primary and secondary manifolds
This division allows rapid and cooler engine starts.
The divider valve also drains fuel from the fuel nozzles during engine shutdown into an ecology system.

37
Q

At what pressure is the fuel filter bypassed?

A

There is no external fuel filter blockage indicators on the PW210S engine. In addition, there is no fuel filter bypass capability on the P&W 210S engine.

38
Q

What is the function of the fuel nozzles and what are its components?

A

Fuel is injected into the combustion chamber
through the fuel manifold. The fuel manifold consist of 10 duplex (primary/ secondary air blast) fuel nozzles and three simplex (secondary/air blast) fuel nozzles.

All 10 duplex nozzles open up to provide fuel
and air at the beginning of the engine start
cycle. When fuel pressure reaches 140 psi, the
simplex nozzles open to assist in the start and
control of the ITT.

39
Q

At what pressure will the simplex nozzles open?

A

When fuel pressure reaches 140 psi, the
simplex nozzles open to assist in the start and
control of the ITT.

40
Q

How many boost pumps does the PW210S have?

A

The airframe fuel tanks do not have fuel boost

pumps.

41
Q

What is the function of the fuel temperature sensor?

A

The fuel temperature sensor embedded in the FCU
measures fuel temperature downstream of the FOHE.

Fuel temperature is used to detect a malfunction of the FOHE.

Maintenance is required when a low fuel pressure or fuel filter impending blockage indication is detected.
Maintenance is also required when a low or high fuel temperature is detected.

42
Q

What controls the position of the inlet guide vanes IGV?

A

The EEC provides position control of the Inlet Guide Vanes IGV.

The EEC varies the fuel pressure, via a
torque motor in the FCU, to the actuator that
positions the IGV at the required angles.

43
Q

How can the PW210S engines be primed?

A

There is no PRIME fuel switch position. The engines are self priming.

44
Q

How are the fuel and engine switches in the over head quadrant connected to the engine?

A

No installed rigging cables are required for
engine or fuel operation.

The S-76D uses upgraded pots with redundant rotary variable differential transducers (RVDTs) to transmit
the position of engine and fuel switch position
to the EECs.

45
Q

Where is the Permanent Magnet Alternator (PMA) located?

A

The PMA is a dual wound, three-phase AC
unit that is integrated into the FCU.

The PMA inside the FCU is driven by the compressor
rotor (NG)

The PMA provides AC electrical power
( through a dedicated internal alternator ) to the
EEC when the engine is running above 81%
NG

46
Q

How is the Ng Cockpit display generated?

A

The EEC derives a proportional NG speed
(rpm) from the phase signal of the PMA.

The EEC then processes this signal and transmits
the reading to the NG cockpit display.

A lossof the PMA results in a major degrade of the
EECs that produces a ENGINE 1/2 FAIL IDLE
condition.

47
Q

What happens if you lose the PMA?

A

A loss of the PMA results in a major degrade of the
EECs that produces an ENGINE 1/2 FAIL IDLE
condition

48
Q

What provides the power turbine speed (Np) and the engine torque (TQ) signals?

A

The Np/Torque sensor.

its a dual coil magnetic sensor (Np/TQ) which provides
the power turbine speed (Np) and engine torque
(TQ) signals. The sensor on the left side of
the reduction gearbox (RGB) is integral to the
engine electrical wiring harness.

The EEC derives the Np speed (rpm) from the
output shaft toothed wheel in the RGB.

The torque (TQ) measurement is based on the angular
twist of the inner torque shaft located inside the non-twisting reference shaft.
49
Q

What happens if you lose the Np/Torque Sensor?

A

The loss of the Np/TQ sensor results in the engine

failing to idle speed.

50
Q

In the event of a power turbine overspeed, at what Np value will the power turbine blades shed?

A

In the unlikely event of a power turbine over-speed caused by a drive system failure, power turbine blades shed at approximately 150% Np.

Internal containment rings keep resultant debris within the containment area.

51
Q

Where is the ITT measured from?

A

The T6 system consists of a braided wiring
harness with eight individual thermocouple
probes (four thermocouples per EEC channel)
connected in parallel.

The thermocouple probes are installed on the
exhaust case and protrude into the gas path.

They are connected in series to the wiring harness
which sends their signal to the EECs for
corrected inter-turbine temperature (ITT) when
combined with the engine oil temperature.

The information is then forwarded for display on
the MFD as (ITT).

52
Q

Where are the EECs mounted?

A

The EECs are mounted on both sides of the

forward tail section

53
Q

What is the function of the Data Collection Unit (DCU) in the FADEC?

A 
The FADEC also includes a data collection unit
(DCU) that:
• Detects/stores indications of faults
• Counts/stores engine life cycles
• Power assurance checks
• EEC faults/counters/OEI power use
54
Q

What type of Nr overspeed protection does the PW 210S engine have?

A

No overspeed protection is provided because
the engine is designed to shed the NG and/or
Np turbine blades and contain the turbine rotor
blades if an overspeed occurs. The blade pieces
will exit via the exhaust.

55
Q

What happens during dual generator operations if the FADEC Controlled Load Shed (FCLS) system activates?

A

During dual DC generator operation, activation of the FCLS system causes the DC1 and DC2 MON bus
contactors and the BATT bus contactor to open,
temporarily shedding the battery charging current
demand and certain non-essential electrical
loads (air conditioner) from the DC generators.

On single DC generator operation, only the
battery charging is shed because the monitor
buses have already been previously shed.

After the engines accelerate, the EECs disengage the
FCLS system and all of the buses are restored

The FCLS system can be tested on the ground
when both engines are running at idle using
start/idle buttons on the engine throttles.

A white FCLS TEST IN PROG advisory illuminates
while the FCLS system is being tested.

56
Q

When will one EEC command both igniter plugs to spark?

A

Each EEC channel has control over its individual
spark igniter installed at the 4 and 8 o’clock
positions on the gas generator case adjacent to
the fuel manifolds and nozzles.

During a normal engine start, the EEC channel in charge
uses its own designated spark ignitor plug.

If a hung start is detected, an inflight start is
attempted, or the OAT is less that minus 20°C,
the controlling EEC automatically commands
both ignitor plugs to spark.

57
Q

What powers the ignition system?

A

The No. 1 and No. 2 DC ESS buses power the

ignition system.

58
Q

At what Ng value during the start sequence will the EEC command the starter off?

A

Both Channel A or B EECs alternate starts
and are capable of commanding the starter on
during the start sequence and off when the
engine reaches approximately 68% NG.

Upon reaching idle, the starting EEC turns over control
of the FCU to the other EEC. The starter
is dropped by the EEC and then becomes a DC generator supplying 28 VDC to the electrical system.

59
Q

At what Ng value during the start sequence will the EEC command the ignition system off?

A

The ignition system is also commanded by
the EEC to turn off when the engine reaches
approximately 50% NG.

60
Q

How does the EEC prevent compressor stalls during engine starts?

A

The EEC prevents compressor stalls during
start by controlling the inlet guide vanes ( IGV ) position with engine fuel pressure.

The IGV is normally partially open during the start at low power conditions and fully open when at a high power
condition.

IGV position is scheduled as a function of NG speed and ambient pressure (Pa).

61
Q

At what Ng value will the EEC introduce fuel and ignition into the engine?

A

During the start, the EEC commands the fuel metering valve to introduce fuel and ignition at approximately 8% NG

62
Q

At what ITT value will the engines shut down to prevent a hot start in flight?

A

Automatic abort hot start protection (on ground only) is available when ITT reaches 765°C.

63
Q

How can both engines be started at the same time in an emergency?

A

The FADEC prevents both engines from starting

at the same time.

64
Q

What is the duration of a normal start ?

A

35 to 45 seconds.

65
Q

What is the ground idle speed?

A

70% Ng

66
Q

At what Nr value will you expect the droop stops to engage?

A

45% Nr

67
Q

Why must you wait for 0% Ng before putting the battery off?

A 
Do not select the battery switch to
OFF before the speed of both engines
decrease to 0% NG. This allows the
DCU to record all engine data during
the shutdown.
68
Q

What is Blow Away Power?

A

When the engines are in an AEO blowaway
power condition, (< 100% NR), a 10 second
transient limit of 115% TQ will occur. If the
rotor continues to droop < 91% NR, the TQ, ITT,
and NG limits are changed to the 30-second OEI
level.

69
Q

What conditions must be met for the ARINC to detect the blow away power

A

ARINC detects the blowaway power limit
increase if the following conditions are met:
• No OEI conditions exists AND
• NR approximately =100%

70
Q

What conditions must be met for the engines to exit blow away power and revert to AEO take off limits?

A

The normal AEO, TQ, ITT, and NG take-off
limits are restored after the following conditions are met

• NR >106% for 10 seconds on both
engines
• ITT < takeoff ITT limit on both engines
• NG < Takeoff NG limit on both engines

OR when any of the following conditions are met:

• Engine throttle is not at FLY on either
engine
• OEI is detected on either engine

71
Q

How can you disable all six chip detectors?

A

Do not pull the CHIP DET circuit
breaker on the No. 1 DC ESS bus
because it will disable all six chip
detectors.

72
Q

At what pressure differential will engine oil filter bypass occur?

A

35 psid

73
Q

What makes up the gas generator section ?

A

The gas generator section includes an accessory gear box and a two-stage compressor driven by a single stage compressor turbine. (RFM)

74
Q

What makes the power section of the S76D engines

A

The power section is a two stage axial flow power turbine that drives the output shaft.

75
Q

What controls the engine operation?

A

Each engine has an independent Full Authority Digital Engine Control System (FADEC) which controls the engine’s operation.

The engine control system has two major components: an Electronic Engine Control (EEC) and a Fuel Control Unit (FCU). (RFM)

76
Q

Where is the FCU installed ?

A

The FCU is installed on the accessory gear box section of the engine (RFM)

77
Q

What makes up the FCU (Fuel Control Unit)?

A

The FCU has an integrated multi stage fuel pump, fuel filter, dual coil stepper motor, and Fuel Metering Unit (FMU).

S76D SYSTEMS (5 decks)

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